ORCID Profile
0000-0003-1601-1540
Current Organisation
University of Queensland
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Psychology | Sensory Processes, Perception And Performance | Sensory Processes, Perception and Performance | Technical, Further and Workplace Education | Virtual Reality and Related Simulation | Virtual Reality And Related Simulation | Biological Psychology (Neuropsychology, Psychopharmacology, | Environmental And Occupational Health And Safety | Road And Rail Transportation | Cognitive Science | Transport Engineering | Transportation and Freight Services | Neurocognitive Patterns and Neural Networks | Zoology | Knowledge Representation and Machine Learning | Computer-Human Interaction | Comparative Physiology | Mechanical Engineering | Neurobiology | Motor Control | Behavioural Ecology | Transport Engineering | Simulation And Modelling | Learning, Memory, Cognition And Language | Neurocognitive Patterns And Neural Networks | Psychological Methodology, Design And Analysis | Planning And Problem Solving | Psychology and Cognitive Sciences not elsewhere classified | Human Movement and Sports Science | Autonomous Vehicles | Sensory Systems | Central Nervous System |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in Psychology and Cognitive Sciences | Road safety | Automotive equipment | Education and Training not elsewhere classified | Behavioural and cognitive sciences | Occupational health (excl. economic development aspects) | Expanding Knowledge in Technology | Expanding Knowledge in Engineering | Expanding Knowledge in the Biological Sciences | Vocational education and training | Biological sciences | Rail transport | Other road transport | Mathematical sciences | Civil | Education and training not elsewhere classified | Road Safety | Nervous system and disorders | Application Tools and System Utilities | Automotive Equipment
Related Links
Publications
When flow is not enough: evidence from a lane changing task
Publisher: Springer Science and Business Media LLC
Date: 07-08-2020
DOI: 10.1007/S00426-018-1070-Z
Abstract: Humans are able to estimate their heading on the basis of optic flow information and it has been argued that we use flow in this way to guide navigation. Consistent with this idea, several studies have reported good navigation performance in flow fields. However, one criticism of these studies is that they have generally focused on the task of walking or steering towards a target, offering an additional, salient directional cue. Hence, it remains a matter of debate as to whether humans are truly able to control steering in the presence of optic flow alone. In this study, we report a set of maneuvers carried out in flow fields in the absence of a physical target. To do this, we studied the everyday task of lane changing, a commonplace multiphase steering maneuver which can be conceptualized without the need for a target. What is more (and here is the crucial quirk), previous literature has found that in the absence of visual feedback, drivers show a systematic, asymmetric steering response, resulting in a systematic final heading error. If optic flow is sufficient for controlling navigation through our environment, we would expect this asymmetry to disappear whenever optic flow is provided. However, our results show that this asymmetry persisted, even in the presence of a flow field, implying that drivers are unable to use flow to guide normal steering responses in this task.
Flexible Resource Allocation for the Detection of Changing Visual Features
Publisher: SAGE Publications
Date: 2011
DOI: 10.1068/P6892
Abstract: Failure to detect change under circumstances where visual input is interrupted or attention is distracted is indicative of the capacity limits of visual short-term memory. The current study attempts to probe the nature of these limits. In experiment 1, the appearance of single Gabor patches was altered across colour, size, or speed, and set size was manipulated by means of a visual cue. In experiment 2, performance for detecting single and multiple changes to Gabor patches was compared under the constraint that the inherent detectability of each in idual change was the same. Experiment 1 yielded a particular set size (4) and a particular level of change magnitude at which performance was equivalent across change type. On the basis of these parameter values, experiment 2 revealed that the detectability of two features changing within one object was the same as the detectability of a single feature changing across two objects, and that this level of detectability could be predicted by a simple model of probability summation. Together, these results suggest that performance is determined by the magnitude of featural changes independently of the way they are distributed across objects. We suggest they are adequately explained by a flexible-resource-allocation model rather than a slot-allocation model.
An unexpected role for visual feedback in vehicle steering control
Publisher: Elsevier BV
Date: 02-2002
DOI: 10.1016/S0960-9822(02)00685-1
Abstract: Some motor tasks can be completed, quite literally, with our eyes shut. Most people can touch their nose without looking or reach for an object after only a brief glance at its location. This distinction leads to one of the defining questions of movement control: is information gleaned prior to starting the movement sufficient to complete the task (open loop), or is feedback about the progress of the movement required (closed loop)? One task that has commanded considerable interest in the literature over the years is that of steering a vehicle, in particular lane-correction and lane-changing tasks. Recent work has suggested that this type of task can proceed in a fundamentally open loop manner, with feedback mainly serving to correct minor, accumulating errors. This paper reevaluates the conclusions of these studies by conducting a new set of experiments in a driving simulator. We demonstrate that, in fact, drivers rely on regular visual feedback, even during the well-practiced steering task of lane changing. Without feedback, drivers fail to initiate the return phase of the maneuver, resulting in systematic errors in final heading. The results provide new insight into the control of vehicle heading, suggesting that drivers employ a simple policy of "turn and see," with only limited understanding of the relationship between steering angle and vehicle heading.
Thresholds for the Detection of Changing Visual Features
Publisher: SAGE Publications
Date: 2011
DOI: 10.1068/P6890
Abstract: Change blindness refers to the difficulty observers have in detecting otherwise obvious changes to visual stimuli, when these changes are masked in some way. Typically, change blindness is studied by using complex visual scenes and complex changes to these scenes. In the current study, we used a more controlled visual environment, presenting observers with a series of oriented, sinusoidal patterns (Gabors), one of which underwent a change during a blanking of the screen. Changes were made to different features (size, colour, spatial frequency, and speed) with the target – distractor discriminability varying. The detectability of these changes was quantified by calculating psychometric functions and thresholds for each in idual observer. Thresholds for the detection of changing features were higher than those for non-changing features, but thresholds for both tasks show consistency across observers. Psychometric-function slopes show consistency across observers and change type only for non-changing targets. For changing targets, psychometric-function slopes show no obvious pattern across observers or change types. We suggest this reflects vSTM treating different features as abstract, interchangeable tokens, as alternative explanations (such as additional noise in vSTM) can be ruled out.
Corrections to: The prototype effect revisited: Evidence for an abstract feature model of face recognition
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 2012
DOI: 10.1167/12.6.1
Learning illumination- and orientation-invariant representations of objects throughtemporal association
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 07-2009
DOI: 10.1167/9.7.6
Visual attention affects temporal estimation in anticipatory motor actions
Publisher: Springer Science and Business Media LLC
Date: 23-06-2011
DOI: 10.1007/S00221-011-2772-2
Abstract: The production of accurate motor actions requires successful extraction of relevant information about the target of that action. By the same token, it also requires the successful exclusion of potentially distracting, irrelevant information. This study sought to determine the impact of transient visual distractions on performance in an anticipatory timing task, in particular the temporal and spatial relationship between distractor and target at which maximal distraction occurs. The results support the notion of a critical temporal and spatial window of distraction which provides insight into the visuomotor processes underlying distraction.
Stroke hospital admission rates in Brisbane and Queensland in 2015: Data from 11,072 cases
Publisher: SAGE Publications
Date: 03-10-2019
Abstract: Little data exist on the incidence of stroke in Australia. Our aim was to report age and sex disparities in hospital admission for stroke in Queensland, Australia's most populous northern state. We identified all patients admitted to hospital in Queensland with a diagnosis of stroke from January to December 2015. Among 25,776 admissions with a diagnosis of stroke or TIA and related sequelae, stroke was the principal diagnosis in 11,072 cases of whom 5270 (47.60%) were first-ever stroke. Based on incidents per 100,000 population per year, the crude annual admission rate for first-ever strokes was 110 (95% CI, 107 to 113), 120 (95% CI, 115 to 124) for men and 101 (95% CI, 97 to 105) for women. The corresponding rates adjusted to the world population were 69 (95% CI, 52 to 85), and 88 (95% CI, 70 to 107) adjusted to the European population. Gender and age-adjusted incidence was greater for men than women in all age-groups, except those aged 30–34 years, where occurrence was 10 for men and 16 for women. Based on the outcomes, hospital admission for stroke occurs less frequently in Queensland than in other regions of Australia. Men generally show a higher rate of hospitalization than women, with the notable exception of women aged 30–34, for whom the trend reverses.
Physiological measurement of anxiety to evaluate performance in simulation training
Publisher: Springer Science and Business Media LLC
Date: 09-03-2014
Illuminating gravitational waves: A concordant picture of photons from a neutron star merger
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-12-2017
Abstract: The gravitational wave event GW170817 was caused by the merger of two neutron stars (see the Introduction by Smith). In three papers, teams associated with the GROWTH (Global Relay of Observatories Watching Transients Happen) project present their observations of the event at wavelengths from x-rays to radio waves. Evans et al. used space telescopes to detect GW170817 in the ultraviolet and place limits on its x-ray flux, showing that the merger generated a hot explosion known as a blue kilonova. Hallinan et al. describe radio emissions generated as the explosion slammed into the surrounding gas within the host galaxy. Kasliwal et al. present additional observations in the optical and infrared and formulate a model for the event involving a cocoon of material expanding at close to the speed of light, matching the data at all observed wavelengths. Science , this issue p. 1565 , p. 1579 , p. 1559 see also p. 1554
Discrimination of human faces by archerfish (Toxotes chatareus)
Publisher: Springer Science and Business Media LLC
Date: 07-06-2016
DOI: 10.1038/SREP27523
Abstract: Two rival theories of how humans recognize faces exist: (i) recognition is innate, relying on specialized neocortical circuitry and (ii) recognition is a learned expertise, relying on general object recognition pathways. Here, we explore whether animals without a neocortex, can learn to recognize human faces. Human facial recognition has previously been demonstrated for birds, however they are now known to possess neocortex-like structures. Also, with much of the work done in domesticated pigeons, one cannot rule out the possibility that they have developed adaptations for human face recognition. Fish do not appear to possess neocortex-like cells and given their lack of direct exposure to humans, are unlikely to have evolved any specialized capabilities for human facial recognition. Using a two-alternative forced-choice procedure, we show that archerfish ( Toxotes chatareus ) can learn to discriminate a large number of human face images (Experiment 1, 44 faces), even after controlling for colour, head-shape and brightness (Experiment 2, 18 faces). This study not only demonstrates that archerfish have impressive pattern discrimination abilities, but also provides evidence that a vertebrate lacking a neocortex and without an evolutionary prerogative to discriminate human faces, can nonetheless do so to a high degree of accuracy.
Same/different abstract concept learning by archerfish (Toxotes chatareus)
Publisher: Public Library of Science (PLoS)
Date: 23-11-2015
Reflexive optokinetic nystagmus in younger and older observers under photopic and mesopic viewing conditions
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 12-2006
DOI: 10.1167/IOVS.06-0539
Abstract: To investigate the effect of age on optokinetic nystagmus (OKN) in response to stimuli designed to preferentially stimulate the M-pathway. OKN was recorded in 10 younger (32.3 +/- 5.98 years) and 10 older (65.6 +/- 6.53) subjects with normal vision. Vertical gratings of 0.43 or 1.08 cpd drifting at 5 degrees /s or 20 degrees /s and presented at either 8% or 80% contrast were displayed on a large screen as full-field stimulation, central stimulation within a central Gaussian-blurred window of 15 degrees diameter, or peripheral stimulation outside this window. All conditions apart from the high-contrast condition were presented in a random order at two light levels, mesopic (1.8 cdm(-2)) and photopic (71.5 cdm(-2)). Partial-field data indicated that central stimulation, mesopic light levels, and lower temporal frequency each significantly increased slow-phase velocity (SPV). Although there was no overall difference between groups for partial-field stimulation, full-field stimulation, or low-contrast stimulation, a change in illumination revealed a significant interaction with age: there was a larger decrease in SPV going from photopic to mesopic conditions for the older group than the younger group, especially for higher temporal frequency stimulation. OKN becomes reflexive in conditions conducive to M-pathway stimulation, and this rOKN response is significantly diminished in older healthy adults than in younger healthy adults, indicative of decreased M-pathway sensitivity.
Shape learning and discrimination in reef fish
Publisher: The Company of Biologists
Date: 07-2009
DOI: 10.1242/JEB.028936
Abstract: Coral reef fish live in a complex world of colour and patterns. If they are to survive they need to be able to correctly identify the things they see(e.g. predators, prey) and act accordingly (e.g. flee, feed). This paper investigates whether discrimination is limited to ecologically relevant stimuli or is in fact more adaptable. Our work focuses on the reef damselfish Pomacentrus amboinensis. Within a day or two of capture the fish demonstrated an ability to associate an arbitrary stimulus with a food reward and to discriminate the reward stimulus from a distractor matched along various physical dimensions. In our initial experiments the reward was directly associated with the target. In the final experiment, however, the reward was separated from the target in both space and time, thereby eliminating a weakness applicable to the majority of food reward experiments involving fish namely, the presence of olfactory cues emanating from the feeding tubes. All fish were not only able to solve this task but also showed anticipatory behaviour (also referred to as goal tracking). We conclude that freshly caught reef fish not only are able to quickly learn and discriminate between novel stimuli on the basis of shape but are also able to interpret stimuli as a predictor for the availability of food at a different time and place (anticipatory behaviour).
Steering performance and dynamic complexity in a simulated underground mining vehicle
Publisher: SAGE Publications
Date: 09-2012
Abstract: Research concerning the visuomotor control of steering suggests that some steering systems used in underground shuttle cars are not optimal. This research compared the performance of two groups of participants steering with a joystick interface through a simulated underground mine environment. The joystick employed either first-order or second-order control of heading. Results indicated poorer performance with second-order steering dynamics in the early stages of the experiment, which generally did not improve to levels observed in the first-order group. Poorer overall performance suggests that equipment manufacturers should reconsider the use of second-order steering dynamics in their vehicle designs. Alternately, simulation-based training technologies may have the potential to safely accelerate in idual attainment of competence in the use of second-order steering systems.
Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues
Publisher: Cold Spring Harbor Laboratory
Date: 02-2021
DOI: 10.1101/2021.01.29.428908
Abstract: Human cerebral cortex can produce visuomotor responses that are modulated by contextual and task-specific constraints. However, the distributed cortical network for visuomotor transformations limits the minimal response time of that pathway. Notably, humans can generate express visuomotor responses that are inflexibly tuned to the target location and occur 80-120ms from stimulus presentation (stimulus-locked responses, SLRs). This suggests a subcortical pathway for visuomotor transformations involving the superior colliculus and its downstream reticulo-spinal projections. Here we investigated whether cognitive expectations can modulate the SLR. In one experiment, we recorded surface EMG from shoulder muscles as participants reached toward a visual target whose location was unpredictable in control conditions, and partially predictable in cue conditions by extrapolating a symbolic cue (75% validity). Valid symbolic cues led to faster and larger SLRs than control conditions invalid symbolic cues produced slower and smaller SLRs than control conditions. This is consistent with a cortical top-down modulation of the putative subcortical SLR-network. In a second experiment, we presented high-contrast targets in isolation (control) or ~24ms after low-contrast stimuli, which could appear at the same (valid cue) or opposite (invalid cue) location as the target, and with equal probability (50% cue validity). We observed faster SLRs than control with the valid low-contrast cues, whereas the invalid cues led to the opposite results. These findings may reflect exogenous priming mechanisms of the SLR network, potentially evolving subcortically via the superior colliculus. Overall, our results support both top-down and bottom-up modulations of the putative subcortical SLR network in humans. Express visuomotor responses in humans appear to reflect subcortical sensorimotor transformation of visual inputs, potentially conveyed via the tecto-reticulo-spinal pathway. Here we show that the express responses are influenced both by symbolic and barely detectable spatial cues about stimulus location. The symbolic cue-induced effects suggest cortical top-down modulation of the putative subcortical visuomotor network. The effects of barely detectable cues may reflect exogenous priming mechanisms of the tecto-reticulo-spinal pathway.
Control order and visuomotor strategy development for joystick-steered underground shuttle cars
Publisher: SAGE Publications
Date: 14-02-2014
Abstract: In this simulator-based study, we aimed to quantify performance differences between joystick steering systems using first-order and second-order control, which are used in underground coal mining shuttle cars. In addition, we conducted an exploratory analysis of how users of the more difficult, second-order system changed their behavior over time. Evidence from the visuomotor control literature suggests that higher-order control devices are not intuitive, which could pose a significant risk to underground mine personnel, equipment, and infrastructure. Thirty-six naive participants were randomly assigned to first- and second-order conditions and completed three experimental trials comprising sequences of 90° turns in a virtual underground mine environment, with velocity held constant at 9 km/h −1 . Performance measures were lateral deviation, steering angle variability, high-frequency steering content, joystick activity, and cumulative time in collision with the virtual mine wall. The second-order control group exhibited significantly poorer performance for all outcome measures. In addition, a series of correlation analyses revealed that changes in strategy were evident in the second-order group but not the first-order group. Results were consistent with previous literature indicating poorer performance with higher-order control devices and caution against the adoption of the second-order joystick system for underground shuttle cars. Low-cost, portable simulation platforms may provide an effective basis for operator training and recruitment.
Comparison of functional and anatomical estimations of visual acuity in two species of coral reef fish
Publisher: The Company of Biologists
Date: 2017
DOI: 10.1242/JEB.149575
Abstract: The high contrast, complex patterns typical of many reef fish serve several purposes, including providing disruptive camouflage and a basis for vision-based communication. In trying to understand the role of a specific pattern it is important to first assess the extent to which an observer can resolve the pattern, itself determined, at least in part, by the observer’s visual acuity. In this study, we study the visual acuity of two species of reef fish using both anatomical and behavioural estimates. The two species in question share a common habitat but are members of different trophic levels (predator vs. herbivore/omnivore) and perform different visual tasks. On the basis of the anatomical study we estimated visual acuity to lie between 4.1 – 4.6 cycles per degree (cpd) for Pomacentrus amboinensis and 3.2 – 3.6 cpd for Pseudochromis fuscus. Behavioural acuity estimates were considerably lower, ranging between 1.29 and 1.36 cpd for Pomacentrus amboinensis and 1.61 and 1.71 cpd for Pseudochromis fuscus. Our results show that two species from the same habitat have only moderately ergent visual capabilities, despite differences in their general life histories. The difference between anatomical and behavioural estimates is an important finding as the majority of our current knowledge on the resolution capabilities of reef fish comes from anatomical measurements. Our findings suggest that anatomical estimates may represent the highest potential acuity of fish but are not indicative of actual performance, and that there is unlikely to be a simple scaling factor to link the two measures across all fish species.
Microsaccades and covert attention: Evidence from a continuous, divided attention task
Publisher: University of Bern
Date: 28-06-2019
DOI: 10.16910/JEMR.12.6.6
Abstract: A substantial question in understanding expert behavior is isolating where experts look, and which aspects of their environment they process. While tracking the position of gaze provides some insight into this process, our ability to attend covertly to regions of space other than the current point of fixation, severely limits the diagnostic power of such data. Over the past decade, evidence has emerged suggesting that microscopic eye movements present during periods of fixation may be linked to the spatial distribution of covert attention, potentially offering a powerful tool for studying expert behavior. To date, the majority of studies in this field have tested the link under the constraints of a trial by trial, forced-response task. In the current study we sought to examine the effect when participants performed a continuous, ided-attention task, with the hope of bridging the gap to a range of more ecological, real-world tasks. We report various aspects of the eye movement and response data including (i) the relationship between microsaccades and drift correction, (ii) response behavior in brief time periods immediately following a microsaccade, (iii) response behavior briefly preceding a microsaccade. Analysis failed to reveal a link between task accuracy and the direction of a microsaccade. Most striking however, we found evidence for a timelocked relationship between the side of space responded to and the direction of the most recent microsaccade. The paper hence provides preliminary evidence that microsaccades may indeed be used to track the ongoing allocation of spatial attention.
The dynamics of perceptual rivalry in bistable and tristable perception
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 20-02-2013
DOI: 10.1167/13.2.24
Abstract: Human observers are extremely adept at correctly interpreting the visual input that they receive despite its inherent ambiguity. There are, however, situations in which no single, valid interpretation exists and perception oscillates. Such situations offer insight into the processes underlying perception, as they reveal the conditions under which our percept can alter in the presence of an unchanging physical stimulus. Many studies have focused on perceptual switching during binocular and monocular rivalry, or when viewing ambiguous figures. The majority of these studies have focused on bistable phenomena. In this paper we report the study of a range of ambiguous stimuli that provoke tristable perception, thereby providing a more exacting test bed for current models. We find that subjects spontaneously move from periods of bistable to tristable perception and that this results in a characteristic change in the rate of perceptual switching. In contrast to reports for bistable stimuli, we find only weak evidence for consistency in the relative switch rates of in iduals across our test stimuli and explain why our results are inconsistent with the theory of interhemispheric switching. We go on to describe how the results are, instead, largely consistent with models of rivalry based on mutual inhibition and adaptation.
Using spatio-temporal correlations to learn invariant object recognition
Publisher: Elsevier BV
Date: 12-1996
DOI: 10.1016/S0893-6080(96)00041-X
Abstract: A competitive network is described which learns to classify objects on the basis of temporal as well as spatial correlations. This is achieved by using a Hebb-like learning rule which is dependent upon prior as well as current neural activity. The rule is shown to be capable of outperforming a supervised rule on the cross validation test of an invariant character recognition task, given a relatively small training set. It is also shown to outperform the supervised version of Fukushima's Neocognitron ([Fukushima, 1980]), on a larger training set. Copyright 1996 Elsevier Science Ltd.
Learning to recognize objects
Publisher: Elsevier BV
Date: 1999
DOI: 10.1016/S1364-6613(98)01261-3
Abstract: Evidence from neurophysiological and psychological studies is coming together to shed light on how we represent and recognize objects. This review describes evidence supporting two major hypotheses: the first is that objects are represented in a mosaic-like form in which objects are encoded by combinations of complex, reusable features, rather than two-dimensional templates, or three-dimensional models. The second hypothesis is that transform-invariant representations of objects are learnt through experience, and that this learning is affected by the temporal sequence in which different views of the objects are seen, as well as by their physical appearance.
The influence of temporal predictability on express visuomotor responses
Publisher: Cold Spring Harbor Laboratory
Date: 31-08-2020
DOI: 10.1101/2020.08.28.269449
Abstract: Volitional visuomotor responses in humans are generally thought to manifest 100ms or more after stimulus onset. Under appropriate conditions, however, much faster target-directed responses can be produced at upper limb and neck muscles. These “express” responses have been termed stimulus-locked responses (SLRs) and are proposed to be modulated by visuomotor transformations performed subcortically via the superior colliculus. Unfortunately, for those interested in studying SLRs, these responses have proven difficult to detect consistently across in iduals. The recent report of an effective paradigm for generating SLRs in 100% of participants appears to change this. The task required the interception of a moving target that emerged from behind a barrier at a time consistent with the target velocity. Here we aimed to reproduce the efficacy of this paradigm for eliciting SLRs and to test the hypothesis that its effectiveness derives from the predictability of target onset time as opposed to target motion per se . In one experiment, we recorded surface EMG from shoulder muscles as participants made reaches to intercept temporally predictable or unpredictable targets. Consistent with our hypothesis, predictably timed targets produced more frequent and stronger SLRs than unpredictably timed targets. In a second experiment, we compared different temporally predictable stimuli and observed that transiently presented targets produced larger and earlier SLRs than sustained moving targets. Our results suggest that target motion is not critical for facilitating the expression of an SLR and that timing predictability does not rely on extrapolation of a physically plausible motion trajectory. These findings provide support for a mechanism whereby an internal timer, probably located in cerebral cortex, primes the processing of both visual input and motor output within the superior colliculus to produce SLRs.
The face-in-the-crowd effect: Threat detection versus isofeature suppression and collinear facilitation
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 09-07-2019
DOI: 10.1167/19.7.6
Abstract: Are people biologically prepared for the rapid detection of threat posed by an angry facial expression, even when it is conveyed in the form of a schematic line drawing? Based on visual search times, the current literature would suggest that the answer is yes. But are there low-level explanations for this effect? Here, we present visual search results for schematic faces using current best practice, based on a concentric search array and set size manipulation. Using this approach, we replicate the classic search advantage for angry over happy faces. However, we also report a comparable effect when abstract plus- and square-shaped stimuli-derived from the angry and happy schematic faces respectively-are used within the same paradigm. We then go on to demonstrate that, while reduced, the effect remains after removal of the circular surround, bringing us closer to the source of the effect. We explore the possibility that the source of this search asymmetry could be the iso-feature suppression and collinear facilitation model proposed in Li's (1999a, 1999b, and 2002) bottom-up model of saliency. Simulations with this model using the abstract stimuli align with the corresponding behavioral results (i.e., the plus shape was found to be more salient than the square). Given the deliberate similarities between these abstract shapes and the respective face stimuli, we propose that the underlying cause for the asymmetries typically found using schematic faces, may be more related to early visual processing of line orientation than threat detection.
Assessing the realism of colonoscopy simulation: the development of an instrument and systematic comparison of 4 simulators
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.GIE.2011.10.030
Abstract: No useful comparative data exist on the relative realism of commercially available devices for simulating colonoscopy. To develop an instrument for quantifying realism and provide the first wide-ranging empiric comparison. Repeated measures, observational study. Nineteen experienced colonoscopists completed cases on 4 colonoscopy simulators (AccuTouch, GI Mentor II, Koken, and Kyoto Kagaku) and evaluated each device. A medical simulation center in a large tertiary hospital. For each device, colonoscopists completed the newly developed Colonoscopy Simulator Realism Questionnaire (CSRQ), which contains 58 items grouped into 10 subscales measuring the realism of different aspects of the simulation. Subscale scores are weighted and combined into an aggregated score, and there is also a single overall realism item. Overall, current colonoscopy simulators were rated as only moderately realistic compared with real human colonoscopy (mean aggregated score, 56.28/100 range, 48.39-60.45, where 0 = "extremely unrealistic" and 100 = "extremely realistic"). On both overall realism measures, the GI Mentor II was rated significantly less realistic than the AccuTouch, Kyoto Kagaku, and Koken (P < .001). There were also significant differences between simulators on 9 subscales, and the pattern of results varied between subscales. The study was limited to commercially available simulators, excluding ex-vivo models. The CSRQ does not assess simulated therapeutic procedures. The CSRQ is a useful instrument for quantifying simulator realism. There is no clear "first choice" simulator among those assessed. Each has unique strengths and weaknesses, reflected in the differing results observed across 9 subscales. These findings may facilitate the targeted selection of simulators for various aspects of colonoscopy training.
Stress training and simulator complexity: why sometimes more is less
Publisher: Informa UK Limited
Date: 09-2010
The use of virtual reality in acrophobia research and treatment
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.JANXDIS.2009.01.014
Abstract: Acrophobia, or fear of heights, is a widespread and debilitating anxiety disorder affecting perhaps 1 in 20 adults. Virtual reality (VR) technology has been used in the psychological treatment of acrophobia since 1995, and has come to dominate the treatment of numerous anxiety disorders. It is now known that virtual reality exposure therapy (VRET) regimens are highly effective for acrophobia treatment. This paper reviews current theoretical understanding of acrophobia as well as the evolution of its common treatments from the traditional exposure therapies to the most recent virtually guided ones. In particular, the review focuses on recent innovations in the use of VR technology and discusses the benefits it may offer for examining the underlying causes of the disorder, allowing for the systematic assessment of interrelated factors such as the visual, vestibular and postural control systems.
A novel training device for tip control in colonoscopy: preliminary validation and efficacy as a training tool
Publisher: Springer Science and Business Media LLC
Date: 07-06-2017
Increased corticospinal excitability induced by unpleasant visual stimuli
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.NEULET.2010.03.027
Abstract: Pleasant and unpleasant emotional stimuli are frequently conceptualized as motivators for action. This notion was examined using focal transcranial magnetic stimulation (TMS). Ten healthy participants viewed pleasant, neutral, and unpleasant pictures from the International Affective Picture System (IAPS). During picture viewing, focal TMS was applied to the right motor cortex over the area innervating the first dorsal interosseous muscle of the left hand. Corticomotor excitability was larger while viewing negative pictures than while viewing neutral or positive images, as evidenced by greater motor evoked potentials. No difference was found between pleasant and neutral pictures. These results are consistent with models of emotion in which the neural networks underlying negative emotions have selective, direct connections to brain structures that mediate motor responses.
Integration of driving simulator and traffic simulation to analyse behaviour at railway crossings
Publisher: SAGE Publications
Date: 24-05-2013
Abstract: The use of state-of-the-art technology to collect and analyse data has significantly improved the effectiveness of safety studies. Currently, despite the fact that there are many safety systems deployed at railway crossings, only limited research has been conducted to evaluate which of these systems is the most effective in terms of costs and safety. This paper demonstrates a way to evaluate safety at railway crossings using a twin-pronged approach: a driving simulator and traffic simulation software. A number of outputs have been observed from a driving simulator, such as driver compliance rate, vehicle speed profile, acceleration profile, initial braking position and final braking position. The compliance percentage at passive crossings (67 and 72% for a stop sign and rumble strips, respectively) has lower compliance rates compared with active crossings (97 and 93% for flashing red light and in-vehicle audible warning, respectively) at an 80 km/h approach speed. Using a statistical analysis it is shown that speed and acceleration profiles can be used to differentiate the effectiveness of active and passive crossings. These indicators are interpreted and used as input to a traffic simulation, which assists in determining which safety device is more efficient. By integrating driving simulator and traffic simulation models, this approach can be applied to evaluate and compare safety performance without the need to install costly test beds at real railway crossings.
Neural prediction of complex accelerations for object interception
Publisher: American Physiological Society
Date: 02-2012
Abstract: To intercept or avoid moving objects successfully, we must compensate for the sensorimotor delays associated with visual processing and motor movement. Although straightforward in the case of constant velocity motion, it is unclear how humans compensate for accelerations, as our visual system is relatively poor at detecting changes in velocity. Work on free-falling objects suggests that we are able to predict the effects of gravity, but this represents the most simple, limiting case in which acceleration is constant and motion linear. Here, we show that an internal model also predicts the effects of complex, varying accelerations when they result from lawful interactions with the environment. Participants timed their responses with the arrival of a ball rolling within a tube of various shapes. The pattern of errors indicates that participants were able to compensate for most of the effects of the ball acceleration (∼85%) within a relatively short practice (∼300 trials). Errors on catch trials in which the ball velocity was unexpectedly maintained constant further confirmed that participants were expecting the effect of acceleration induced by the shape of the tube. A similar effect was obtained when the visual scene was projected upside down, indicating that the mechanism of this prediction is flexible and not confined to ecologically valid interactions. These findings demonstrate that the brain is able to predict motion on the basis of prior experience of complex interactions between an object and its environment.
Initiation of evasive manoeuvres during self-motion: A test of three hypotheses
Publisher: Springer Science and Business Media LLC
Date: 02-10-2004
DOI: 10.1007/S00221-004-1994-Y
Abstract: To understand performance of evasive and interceptive actions it is important to know how people decide when to initiate a movement-initiating at the 'right' moment is often essential for successful performance. It has been proposed that initiation is triggered when a perceptually derived quantity reaches an invariant criterion value. Candidate quantities include time-to-collision (TTC), distance, and rate of image expansion (ROE), all of which have received empirical support. We studied initiation of an evasive manoeuvre in a computer-simulated steering task in which the observer was required to steer through a stationary visual environment and avoid colliding with an obstacle in their path. The results could not be explained by hypotheses which propose that evasive manoeuvre initiation is based on a fixed criterion value of TTC or distance. The overall pattern was, however, consistent with the use of a criterion ROE value. This was further tested by analyses designed to directly evaluate whether the ROE value used to initiate the response was the same across experimental conditions. Only two of the six participants showed evidence for using the ROE strategy.
Deconstructing acrophobia: physiological and psychological precursors to developing a fear of heights
Publisher: Hindawi Limited
Date: 30-08-2010
DOI: 10.1002/DA.20698
Abstract: Acrophobia is one of the most prevalent phobias, affecting as many as 1 in 20 in iduals. Of course, heights often evoke fear in the general population too, and this suggests that acrophobia might actually represent the hypersensitive manifestation of an everyday, rational fear. In this study, we assessed the role of sensory and cognitive variables in acrophobia. Forty-five participants (Mean age 25.07 years, 71% female) were assessed using a booklet with self-reports as well as several behavioral measures. The data analysis consisted in multivariate linear regression using fear of heights as the outcome variable. The regression analyses found that visual field dependence (measured with the rod and frame test), postural control (measured with the Sharpened Romberg Test), space and motion discomfort (measured with the Situational Characteristics Questionnaire), and bodily symptoms (measured with the Bodily Sensation Questionnaire) all serve as strong predictors for fear of heights (Adjusted r(2)=.697, P<.0001). Trait anxiety (measured with the State Trait Anxiety Inventory Form Y-2) was not related with fear of heights, suggesting that this higher order vulnerability factor is not necessary for explaining this particular specific phobia in a large number of in iduals. The findings reveal that fear of heights is an expression of a largely sensory phenomena, which can produce strong feelings of discomfort and fear in the otherwise calm in iduals. We propose a theory that embraces all these factors and provides new insight into the aetiology and treatment of this prevalent and debilitating fear.
Directional control-response relationships for mining equipment
Publisher: Informa UK Limited
Date: 21-05-2010
DOI: 10.1080/00140131003675109
Abstract: A variety of directional control-response relationships are currently found in mining equipment. Two experiments were conducted in a virtual environment to determine optimal direction control-response relationships in a wide variety of circumstances. Direction errors were measured as a function of control orientation (horizontal or vertical), location (left, front, right) and directional control-response relationships. The results confirm that the principles of consistent direction and visual field compatibility are applicable to the majority of situations. An exception is that fewer direction errors were observed when an upward movement of a horizontal lever or movement of a vertical lever away from the participants caused extension (lengthening) of the controlled device, regardless of whether the direction of movement of the control is consistent with the direction in which the extension occurs. Further, both the control of slew by horizontally oriented controls and the control of device movements in a frontal plane by the perpendicular movements of vertical levers were associated with relatively high rates of directional errors, regardless of the directional control-response relationship, and these situations should be avoided. STATEMENT OF RELEVANCE: The results are particularly applicable to the design of mining equipment such as drilling and bolting machines, and have been incorporated into MDG35.1 Guideline for bolting & drilling plant in mines (Industry & Investment NSW, 2010). The results are also relevant to the design of any equipment where vertical or horizontal levers are used to control the movement of equipment appendages, e.g. cranes mounted to mobile equipment and the like.
Microsimulation modelling of driver behaviour towards alternative warning devices at railway level crossings
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.AAP.2014.05.014
Abstract: Level crossings are amongst the most complex of road safety issues, due to the addition of rail infrastructure, trains and train operations. The differences in the operational characteristics of different warning devices together with varying crossing, traffic or/and train characteristics, cause different driver behaviour at crossings. This paper compares driver behaviour towards two novel warning devices (rumble strips and in-vehicle audio warning) with two conventional warning devices (flashing light and stop sign) at railway level crossings using microsimulation modelling. Two safety performance indicators directly related to collision risks, violation and time-to-collision, were adopted. Results indicated the active systems were more effective at reducing likely collisions compared to passive devices. With the combined application of driving simulation and traffic microsimulation modelling, traffic safety performance indicators for a level crossing can be estimated. From these, relative safety comparisons for the different traffic devices are derived, or even for absolute safety evaluation with proper calibration from field investigations.
Assessing colonoscopic inspection skill using a virtual withdrawal simulation: a preliminary validation of performance metrics
Publisher: Springer Science and Business Media LLC
Date: 12-07-2017
Toward a unified model of face and object recognition in the human visual system
Publisher: Frontiers Media SA
Date: 2013
Contrasting Predictions of Low- and High-Threshold Models for the Detection of Changing Visual Features
Publisher: SAGE Publications
Date: 2012
DOI: 10.1068/P7176
Abstract: Change blindness is the failure of observers to notice otherwise obvious changes to a visual scene when those changes are masked in some way (eg by blotches or a blanking of the screen). Typically, change blindness is taken as evidence that our representation of the visual world is capacity limited. The locus of this capacity limit is thought to be visual short-term memory (vSTM). The capacity of vSTM is usually estimated with a high-threshold model which assumes that each element in the stimulus array is either fully encoded or not encoded at all, and, furthermore, that false alarms can arise only by guessing, not by noise. Low-threshold models, by contrast, suggest that false alarms can arise by noise at the level of detection/discrimination and/or decision. In this study, we use a well-controlled stimulus display in which a single element changes over a blanking of the screen and contrast predictions from a popular high-threshold model of vSTM with the predictions of a low-threshold model (specifically, the s le-size model) of visual search and vSTM. The data were better predicted by the low-threshold model.
The face-in-the-crowd effect: When angry faces are just cross(es)
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 06-01-2011
DOI: 10.1167/10.1.7
Modelling driver behaviour towards innovative warning devices at railway level crossings
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.AAP.2012.11.002
Abstract: Improving safety at railway level crossings is costly and as funds are often limited, it is important to search for cost-effective, evidence-based solutions. The effect that the many existing alternative systems have on driver behaviour is not always known. This paper compares driver behaviour towards two novel warning devices (rumble strips and in-vehicle audio warning) at railway level crossings with two conventional warning devices (flashing light and stop sign). Regression models were developed to reflect driver's responses towards the four different types of devices based on data collected from a driving simulation experiment. The regression models include a binary choice model for predicting the probability of a driver stopping or driving through a railway crossing, as well as mixed regression models for predicting the moment at which a driver will produce specific behavioural responses before stopping at a crossing (e.g. initiation of accelerator release and application of foot-pedal brake). Violation results indicated the active systems produced much higher levels of driver compliance than passive devices. Contributing factors, such as age, gender, speed and types of warning devices were found significant at different approach stages to the level crossings. With the application of such behavioural models and traffic conflict techniques in microscopic simulation tools, traffic safety indicators, such as collision likelihood and time-to-collision can be estimated. From these, relative safety comparisons for the different traffic devices are derived.
Using psilocybin to investigate the relationship between attention, working memory, and the serotonin 1A and 2A receptors
Publisher: MIT Press - Journals
Date: 10-2005
DOI: 10.1162/089892905774597191
Abstract: Increasing evidence suggests a link between attention, working memory, serotonin (5-HT), and prefrontal cortex activity. In an attempt to tease out the relationship between these elements, this study tested the effects of the hallucinogenic mixed 5-HT1A/2A receptor agonist psilocybin alone and after pretreatment with the 5-HT2A antagonist ketanserin. Eight healthy human volunteers were tested on a multiple-object tracking task and spatial working memory task under the four conditions: placebo, psilocybin (215 Ag/kg), ketanserin (50 mg), and psilocybin and ketanserin. Psilocybin significantly reduced attentional tracking ability, but had no significant effect on spatial working memory, suggesting a functional dissociation between the two tasks. Pretreatment with ketanserin did not attenuate the effect of psilocybin on attentional performance, suggesting a primary involvement of the 5-HT1A receptor in the observed deficit. Based on physiological and pharmacological data, we speculate that this impaired attentional performance may reflect a reduced ability to suppress or ignore distracting stimuli rather than reduced attentional capacity. The clinical relevance of these results is also discussed.
Concept learning and the use of three common psychophysical paradigms in the archerfish (Toxotes chatareus)
Publisher: Frontiers Media SA
Date: 24-04-2014
Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans
Publisher: Springer Science and Business Media LLC
Date: 14-09-2007
DOI: 10.1007/S00213-007-0930-9
Abstract: Binocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psychosis. The objective of the study was to explore the proposed relationship between binocular rivalry switch rate and subjective changes in psychological state associated with 5-HT2A receptor activation. This study used psilocybin, the hallucinogen found naturally in Psilocybe mushrooms that had previously been found to induce psychosis-like symptoms via the 5-HT2A receptor. The effects of psilocybin (215 microg/kg) were considered alone and after pretreatment with the selective 5-HT2A antagonist ketanserin (50 mg) in ten healthy human subjects. Psilocybin significantly reduced the rate of binocular rivalry switching and increased the proportion of transitional/mixed percept experience. Pretreatment with ketanserin blocked the majority of psilocybin's "positive" psychosis-like hallucinogenic symptoms. However, ketanserin had no influence on either the psilocybin-induced slowing of binocular rivalry or the drug's "negative-type symptoms" associated with reduced arousal and vigilance. Together, these findings link changes in binocular rivalry switching rate to subjective levels of arousal and attention. In addition, it suggests that psilocybin's effect on binocular rivalry is unlikely to be mediated by the 5-HT2A receptor.
Rapid recalibration of temporal order judgements: Response bias accounts for contradictory results
Publisher: Wiley
Date: 10-09-2020
DOI: 10.1111/EJN.14551
Abstract: Recent history influences subsequent perception, decision-making and motor behaviours. In this article, we address a discrepancy in the effects of recent sensory history on the perceived timing of auditory and visual stimuli. In the synchrony judgement (SJ) task, similar timing relationships in consecutive trials seem more synchronous (i.e. less like the repeated temporal order). This effect is known as rapid recalibration and is consistent with a negative perceptual aftereffect. Interestingly, the opposite is found in the temporal order judgement (TOJ) task (positive rapid recalibration). We aimed to determine whether a simple bias to repeat judgements on consecutive trials (choice-repetition bias) could account for the discrepant results in these tasks. Preliminary simulations and analyses indicated that a choice-repetition bias could produce apparently positive rapid recalibration in the TOJ and not the SJ task. Our first experiment revealed no evidence of rapid recalibration of TOJs, but negative rapid recalibration of associated confidence. This suggests that timing perception was rapidly recalibrated, but that the negative recalibration effect was obfuscated by a positive bias effect. In our second experiment, we experimentally mitigated the choice-repetition bias effect and found negative rapid recalibration of TOJs. We therefore conclude that timing perception is negatively rapidly recalibrated, and this is observed consistently across timing tasks. These results contribute to a growing body of evidence that indicates multisensory perception is constantly undergoing recalibration, such that perceptual synchrony is maintained. This work also demonstrates that participants' task responses reflect judgements that are contaminated by independent biases of perception and decision-making.
Spectral and spatial selectivity of luminance vision in reef fish
Publisher: Frontiers Media SA
Date: 30-09-2014
Contradictory influence of context on predominance during Binocular rivalry
Publisher: Informa UK Limited
Date: 05-2004
DOI: 10.1111/J.1444-0938.2004.TB03168.X
Abstract: Binocular rivalry is a complex process characterised by alternations in perceptual suppression and dominance that result when two different images are presented simultaneously to the left and right eyes. It has been reported recently that the addition of contextual cues will promote the predominance of the context consistent rivalry target. In contrast to Levelt's second proposition (1965), this effect has been found to result exclusively from an increase in the dominance phase duration, while the suppression phase duration remains unaffected. Human subjects were simultaneously presented with a small (2 degrees ) disc consisting of gratings (four cycles per degree) of different orientations to the two eyes. Four experiments were conducted to ascertain the effects of background gratings and contextual colour information on target predominance and phase duration. For each of the four experimental conditions, the orientation and colour of the target gratings and surrounding contextual background were systematically manipulated. In this study, we report an effect opposite to that of Levelt. Contradictory contextual information increases target predominance and phase duration during binocular rivalry. Our results demonstrate that it is possible to promote the dominance of the context contradictory percept with co-linearity, co-chromaticity and orientation cues. In line with previous studies involving context, we find that this effect on predominance is due to an increase in the duration of the dominance rather than the suppression phase. We discuss our findings in respect to those from previous studies and consider high- and low-level processes that may be responsible for these apparently 'contradictory' roles of context on binocular rivalry. In addition, we discuss how the apparent 'anti-Levelt' effect of context can be reinterpreted in a manner that brings it back in line with Levelt's second proposition and raises the question of whether 'suppressability' plays a disproportionately large role in determining the duration of perceptual phases in binocular rivalry.
A spatial explanation for synchrony biases in perceptual grouping: Consequences for the temporal-binding hypothesis
Publisher: Springer Science and Business Media LLC
Date: 02-2005
DOI: 10.3758/BF03206497
Abstract: If two images are shown in rapid sequential order, they are perceived as a single, fused image. Despite this, recent studies have revealed that fundamental perceptual processes are influenced by extremely brief temporal offsets in stimulus presentation. Some researchers have suggested that this is due to the action of a cortical temporal-binding mechanism, which would serve to keep multiple mental representations of one object distinct from those of other objects. There is now gathering evidence that these studies should be reassessed. This article describes evidence for sensitivity to fixational eye and head movements, which provides a purely spatial explanation for the earlier results. Taken in conjunction with other studies, the work serves to undermine the current body of behavioral evidence for a temporal-binding mechanism.
Designing Virtual Reality Assisted Psychotherapy for Anxiety in Older Adults Living with Parkinson’s Disease: Integrating Literature for Scoping
Publisher: Informa UK Limited
Date: 06-01-2020
Directional control–response compatibility of joystick steered shuttle cars
Publisher: Informa UK Limited
Date: 08-2012
DOI: 10.1080/00140139.2012.700328
Abstract: Shuttle cars are an unusual class of vehicle operated in underground coal mines, sometimes in close proximity to pedestrians and steering errors may have very serious consequences. A directional control-response incompatibility has previously been described in shuttle cars which are controlled using a steering wheel oriented perpendicular to the direction of travel. Some other shuttle car operators are seated perpendicular to the direction of travel and steer the car via a seat mounted joystick. A virtual simulation was utilised to determine whether the steering arrangement in these vehicles maintains directional control-response compatibility. Twenty-four participants were randomly assigned to either a condition corresponding to this design (consistent direction), or a condition in which the directional steering response was reversed while driving in-bye (visual field compatible). Significantly less accurate steering performance was exhibited by the consistent direction group during the in-bye trials only. Shuttle cars which provide the joystick steering mechanism described here require operators to accommodate alternating compatible and incompatible directional control-response relationships with each change of car direction. A virtual simulation of an underground coal shuttle car demonstrates that the design incorporates a directional control-response incompatibility when driving the vehicle in one direction. This design increases the probability of operator error, with potential adverse safety and productivity consequences.
Invariant face and object recognition in the visual system
Publisher: Elsevier BV
Date: 02-1997
DOI: 10.1016/S0301-0082(96)00054-8
Abstract: Neurophysiological evidence is described, showing that some neurons in the macaque temporal cortical visual areas have responses that are invariant with respect to the position, size and view of faces and objects, and that these neurons show rapid processing and rapid learning. A theory is then described of how such invariant representations may be produced in a hierarchically organized set of visual cortical areas with convergent connectivity. The theory proposes that neurons in these visual areas use a modified Hebb synaptic modification rule with a short-term memory trace to capture whatever can be captured at each stage that is invariant about objects as the object changes in retinal position, size, rotation and view. Simulations are then described which explore the operation of the architecture. The simulations show that such a processing system can build invariant representations of objects.
Visual–haptic integration, action and embodiment in virtual reality
Publisher: Springer Science and Business Media LLC
Date: 28-10-2021
DOI: 10.1007/S00426-021-01613-3
Abstract: The current generation of virtual reality (VR) technologies has improved substantially from legacy systems, particularly in the resolution and latency of their visual display. The presentation of haptic cues remains challenging, however, because haptic systems do not generalise well over the range of stimuli (both tactile and proprioceptive) normally present when interacting with objects in the world. This study investigated whether veridical tactile and proprioceptive cues lead to more efficient interaction with a virtual environment. Interaction in the world results in spatial and temporal correlation of tactile, proprioceptive and visual cues. When cues in VR are similarly correlated, observers experience a sense of embodiment and agency of their avatars. We investigated whether sensorimotor performance was mediated by embodiment of the avatar hands. Participants performed a Fitts' tapping task in different conditions (VR with no haptics, active haptics, passive haptics, and on a real touchscreen). The active-haptic condition provided abstract tactile cues and the passive haptic condition provided veridical tactile and proprioceptive cues. An additional (hybrid haptics) condition simulated an ideal passive haptic system. Movement efficiency (throughput) and embodiment were higher for the passive than for the active and no-haptics conditions. However, components of embodiment (perceived agency and ownership) did not predict unique variance in throughput. Improved sensorimotor performance and ratings of presence and realism support the use of passive haptics in VR environments where objects are in known and stable locations, regardless of whether performance was mediated by the sense of embodiment.
The influence of temporal predictability on express visuomotor responses
Publisher: American Physiological Society
Date: 03-2021
Abstract: Express stimulus-driven responses in humans have been proposed to be originated subcortically via the superior colliculus. These short-latency responses are facilitated by the presentation of dynamic visual stimuli. Here, we show that this facilitation is related to the predictable target timing, regardless of its kinematic attributes. We propose that the superior colliculus can be primed to generate express stimulus-driven motor responses via cortical top-down projection.
Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues
Publisher: American Physiological Society
Date: 11-2021
Abstract: Express visuomotor responses in humans appear to reflect subcortical sensorimotor transformation of visual inputs, potentially conveyed via the tecto-reticulo-spinal pathway. Here we show that the express responses are influenced by both symbolic and barely detectable spatial cues about stimulus location. The symbolic cue-induced effects suggest cortical top-down modulation of the putative subcortical visuomotor network. The effects of barely detectable cues may reflect exogenous facilitation mechanisms of the tecto-reticulo-spinal pathway.
Naïve Physics in Vehicle Steering Control
Publisher: Springer International Publishing
Date: 2014
Assessment of colorectal polyp recognition skill: development and validation of an objective test
Publisher: Springer Science and Business Media LLC
Date: 20-09-2017
DOI: 10.1007/S00464-016-5243-9
Abstract: The quality of colonoscopy is known to vary. The extent to which colonoscopists can recognize the presence of subtle colorectal lesions by visually distinguishing them from the surrounding mucosa (i.e., polyp recognition skill) may be one of several attributes that influence polyp detection rates. The aim of the present study was to develop and validate the first objective test of polyp recognition skill. Validation study. Twenty-eight experienced colonoscopists and eighty novices took a preliminary 280-item computer-based polyp recognition test. Items were genuine endoscopic images which participants assessed for the presence of "likely polyps." Half included clinically identified polyps. Participants clicked on a suspected lesion or a button marked "no likely polyp", and the main outcome measures were accuracy and response latency. The best items were selected for the final 50-item test. In the preliminary test, experienced colonoscopists correctly identified more polyps than novices (P < .0001) and better discriminated between clinically identified polyps and non-polyp features (as measured by d', P < .0001). For polyp items, the experienced group also responded faster (P < .01). Effect sizes were large for accuracy (Cohen's d = 3.22) and d' (Cohen's d = 3.22). The 50 final test items produced comparable results for accuracy, d', and response latency. For both versions of the test, score scale reliability was high for both polyp and non-polyp items (α = .82 to .97). The observed experienced-novice differences support the construct validity of the performance measures derived from the tests, indicating that polyp recognition skill can be quantified objectively. The final test may potentially be used to assess trainees, but test sensitivity may be insufficient to make fine-grained distinctions between different skill levels among experienced colonoscopists. More sensitive future tests may provide a valuable supplement to clinical detection rates, allowing objective comparisons between skilled colonoscopists.
Rapid recalibration of temporal order judgements: Response bias accounts for contradictory results
Publisher: Cold Spring Harbor Laboratory
Date: 13-03-2019
DOI: 10.1101/576249
Abstract: Recent findings indicate that timing perception is systematically changed after only a single presentation of temporal asynchrony. This effect is known as rapid recalibration. In the synchrony judgement task, similar timing relationships in consecutive trials seem more synchronous ( positive rapid recalibration Van der Burg et al., 2013, 2015). Interestingly, the direction of this effect is reversed for temporal order judgements ( negative rapid recalibration Roseboom, 2019). We aimed to determine whether negative rapid recalibration of temporal order judgements (TOJs) reflects genuine rapid temporal recalibration, or a choice-repetition bias unrelated to timing perception. In our first experiment we found no evidence of rapid recalibration of TOJs, but positive rapid recalibration of associated confidence. This suggests that timing perception had rapidly recalibrated, but that this was undetectable in TOJs, plausibly because the positive recalibration effect was obfuscated by a large negative bias effect. In our second experiment, we dissociated participants’ previous TOJ from the most recently presented timing relationship, mitigating the choice-repetition bias effect, and found evidence of positive rapid recalibration of TOJs. We therefore conclude that timing perception is rapidly recalibrated positively for both synchrony and temporal order judgements. It remains unclear whether rapid recalibration occurs at the level of sensory processing, leading to similar effects in all subsequent judgements, or reflects a generalised decision-making strategy.
Effects of temporal association on recognition memory
Publisher: Proceedings of the National Academy of Sciences
Date: 03-04-2001
Abstract: The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.
The role of object motion in forging long-term representations of objects
Publisher: Informa UK Limited
Date: 02-2002
Performance consequences of alternating directional control-response compatibility: Evidence from a coal mine shuttle car simulator
Publisher: SAGE Publications
Date: 08-2007
Abstract: Objective: To investigate error and reaction time consequences of alternating compatible and incompatible steering arrangements during a simulated obstacle avoidance task. Background: Underground coal mine shuttle cars provide an ex le of a vehicle in which operators are required to alternate between compatible and incompatible steering configurations. Methods: This experiment examines the performance of 48 novice participants in a virtual analogy of an underground coal mine shuttle car. Participants were randomly assigned to a compatible condition, an incompatible condition, an alternating condition in which compatibility alternated within and between hands, or an alternating condition in which compatibility alternated between hands. Results: Participants made fewer steering direction errors and made correct steering responses more quickly in the compatible condition. Error rate decreased over time in the incompatible condition. A compatibility effect for both errors and reaction time was also found when the control-response relationship alternated however, performance improvements over time were not consistent. Isolating compatibility to a hand resulted in reduced error rate and faster reaction time than when compatibility alternated within and between hands. Conclusion: The consequences of alternating control-response relationships are higher error rates and slower responses, at least in the early stages of learning. Application: This research highlights the importance of ensuring consistently compatible human-machine directional control-response relationships.
When action conditions perception: Evidence of cross-modal cue recruitment
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 09-11-2016
DOI: 10.1167/16.14.6
Abstract: Goal-directed movement, such as reaching to touch an object, relies heavily on vision. Vision guides our motor system not only during initial targeting but also during online movement correction and error-driven learning. But it is not all one-way traffic. This paper reports a situation in which this perceptual-motor interaction runs in reverse, when action affects concurrent perceptual experience. More to the point, the paper reveals that visual perception is subject to change through learned (even arbitrary) visuomotor associations. By considering a situation in which the perceptual decision is dichotomous, this paper reveals that the brain readily harnesses motor behavior to constrain the formation of a visual percept.
Visuomotor control of steering: the artefact of the matter
Publisher: Springer Science and Business Media LLC
Date: 09-01-2011
DOI: 10.1007/S00221-010-2530-X
Abstract: Previous behavioural research (Land and Horwood in Nature 377:339-340, 1995) indicates that surprisingly little visual information is required to effect smooth and accurate steering through a curving roadway. Based on results from a driving simulator study, Land and Horwood reported that viewing the roadway through two horizontal apertures, one degree of visual angle in height, can result in steering performance which is indistinguishable from that obtained with the whole scene visible. The position of the apertures in the visual field, they claimed, is crucial higher up leads to less accurate but more stable steering responses, whilst lower down leads to jerky steering but more accurate lane-keeping. These findings are consistent with a two-stage model of steering control proposed by Donges in Human Factors 20:691-707 (1978). However, in a driving simulator, the temporal lag between the input signal received from a control device and the output presented on the display can have profound effects on steering behaviour. In two experiments, we show that the effect of aperture position on steering accuracy and stability is pronounced when a slow frame update rate is used (7.2 Hz, as used by Land and Horwood in Nature 377:339-340, 1995), but largely attenuated with a faster update rate (72 Hz). These results are consistent with the broader empirical literature dealing with temporal delays in manual tracking, and urge a critical reappraisal of the behavioural evidence for the two-stage steering model.
Evaluating Driver Behavior Toward Innovative Warning Devices at Railway Level Crossings Using a Driving Simulator
Publisher: Informa UK Limited
Date: 06-2013
Limitations of feedforward control in multiple-phase steering movements
Publisher: Springer Science and Business Media LLC
Date: 29-04-2009
DOI: 10.1007/S00221-009-1813-6
Abstract: When attempting to perform bi-phasic steering movements (such as a lane change) in the absence of visual and inertial feedback, drivers produce a systematic heading error in the direction of the lane change (Wallis et al., Curr Biol 12(4):295-299, 2002 J Exp Psychol Hum Percept Perform 33(55):1127-1144, 2007). Theories of steering control which employ exclusively open-loop control mechanisms cannot accommodate this finding. In this article we show that a similar steering error occurs with obstacle avoidance, and offer compelling evidence that it stems from a seemingly general failure of human operators to correctly internalise the dynamics of the steering wheel. With respect to lateral position, the steering wheel is an acceleration control device, but we present data indicating that drivers treat it as a rate control device. Previous findings from Wallis et al. can be explained the same way. Since an open-loop control mechanism will never succeed when the dynamics of the controller are internalised improperly, we go on to conclude that regular, appropriately timed sensory feedback-predominantly from vision-is necessary for regulating heading, even during well-practiced, everyday manoeuvres such as lane changing and obstacle avoidance.
Predicting the efficacy of simulator-based training using a perceptual judgment task versus questionnaire-based measures of presence
Publisher: MIT Press
Date: 02-2013
DOI: 10.1162/PRES_A_00135
Abstract: The quality of a virtual environment, as characterized by factors such as presence and fidelity, is of interest to developers and users of simulators for many reasons, not least because both factors have been linked to improved outcomes in training as well as a reduced incidence of simulator sickness. Until recently, most approaches to measuring these factors have been based on subjective, postexposure questioning. This approach has, however, been criticized because of the shortcomings of self-report and the need to delay feedback or interrupt activity. To combat these problems, recent papers on the topic have proposed the use of behavioral measures to assess simulators and predict training outcomes. Following their lead, this paper makes use of a simple perceptual task in which users are asked to estimate their simulated speed within the environment. A longitudinal study of training outcomes using two of the simulators revealed systematic differences in task performance that matched differences measured using the perceptual task in a separate group of control subjects. A separate analysis of two standard presence questionnaires revealed that they were able to predict learning outcomes on a per in idual basis, but that they were insensitive to the differences between the two simulators. The paper concludes by explaining how behavioral measures of the type proposed here can complement questionnaire-based studies, helping to motivate design aspects of new simulators, prompting changes to existing systems, and constraining training scenarios to maximize their efficacy.
Visual Acuity in a Species of Coral Reef Fish: <b><i>Rhinecanthus aculeatus</i></b>
Publisher: S. Karger AG
Date: 2014
DOI: 10.1159/000356977
Abstract: Coral reef fish present the human observer with an array of bold and contrasting patterns however, the ability of such fish to perceive these patterns is largely unexamined. To understand this, the visual acuity of these animals - the degree to which they can resolve fine detail - must be ascertained. Behavioural studies are few in number and anatomical analysis has largely focused on estimates of ganglion cell density to predict the visual acuity in coral reef fish. Here, we report visual acuity measures for the triggerfish i Rhinecanthus aculeatus. /i Acuity was first assessed using a series of behavioural paradigms and the figures were then contrasted with those obtained anatomically, based on photoreceptor and ganglion cell counts. Behavioural testing indicated an upper behavioural acuity of 1.75 cycles·degree sup -1 /sup , which is approximately the same level of acuity as that of the goldfish i (Carassius /i i auratus). /i Anatomical estimates were then calculated from wholemount analysis of the photoreceptor layer and Nissl staining of cells within the ganglion cell layer. Both of these anatomical measures gave estimates that were substantially larger (7.75 and 3.4 cycles·degree sup -1 /sup for the photoreceptor cells and ganglion cells, respectively) than the level of acuity indicated by the behavioural tests. This indicates that in this teleost species spatial resolution is poor compared to humans (30-70 cycles·degree sup -1 /sup ) and it is also not well indicated by anatomical estimates.
Strategy influences directional control–response compatibility: evidence from an underground coal mine shuttle car simulation
Publisher: Informa UK Limited
Date: 19-12-2015
Damselfish see colour
Publisher: The Company of Biologists
Date: 02-2008
DOI: 10.1242/JEB.016485
The temporal and spatial limits of compensation for fixational eye movements
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.VISRES.2006.01.037
Abstract: High-fidelity eye tracking is combined with a perceptual grouping task to provide insight into the likely mechanisms underlying the compensation of retinal image motion caused by movement of the eyes. The experiments describe the covert detection of minute temporal and spatial offsets incorporated into a test stimulus. Analysis of eye motion on in idual trials indicates that the temporal offset sensitivity is actually due to motion of the eye inducing artificial spatial offsets in the briefly presented stimuli. The results have strong implications for two popular models of compensation for fixational eye movements, namely efference copy and image-based models. If an efference copy model is assumed, the results place constraints on the spatial accuracy and source of compensation. If an image-based model is assumed then limitations are placed on the integration time window over which motion estimates are calculated.
Colour vision in coral reef fish
Publisher: The Company of Biologists
Date: 02-2008
DOI: 10.1242/JEB.012880
Abstract: Over many millions of years, sea creatures have developed a range of light reflectance properties. One ex le is the large variation in the patterns and colours of fish inhabiting the world's coral reefs. Attempts to understand the significance of the colouration have been made, but all too often from the perspective of a human observer. A more ecological approach requires us to consider the visual system of those for whom the colours were intended, namely other sea life. A first step is to understand the sensitivity of reef fish themselves to colour. Physiological data has revealed wavelength-tuned photoreceptors in reef fish, and this study provides behavioural evidence for their application in colour discrimination. Using classical conditioning,freshly caught damselfish were trained to discriminate coloured patterns for a food reward. Within 3–4 days of capture the fish selected a target colour on over 75% of trials. Brightness of the distracter and target were systematically varied to confirm that the fish could discriminate stimuli on the basis of chromaticity alone. The study demonstrates that reef fish can learn to perform two-alternative discrimination tasks, and provides the first behavioural evidence that reef fish have colour vision.
Modulating the Rate and Rhythmicity of Perceptual Rivalry Alternations with the Mixed 5-HT2A and 5-HT1A Agonist Psilocybin
Publisher: Springer Science and Business Media LLC
Date: 26-01-2005
Abstract: Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of perceptual alternations during binocular rivalry was greatly increased 10 h after the consumption of LSD, this study aimed to investigate the pharmacology underlying binocular rivalry and to explore the connection between the timing of perceptual switching and psychosis. Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine, PY) was chosen for the study because, like LSD, it is known to act as an agonist at serotonin (5-HT)1A and 5-HT2A receptors and to produce an altered state sometimes marked by psychosis-like symptoms. A total of 12 healthy human volunteers were tested under placebo, low-dose (115 microg/kg) and high-dose (250 microg/kg) PY conditions. In line with predictions, under both low- and high-dose conditions, the results show that at 90 min postadministration (the peak of drug action), rate and rhythmicity of perceptual alternations were significantly reduced from placebo levels. Following the 90 min testing period, the perceptual switch rate successively increased, with some in iduals showing increases well beyond pretest levels at the final testing, 360 min postadministration. However, as some subjects had still not returned to pretest levels by this time, the mean phase duration at 360 min was not found to differ significantly from placebo. Reflecting the drug-induced changes in rivalry phase durations, subjects showed clear changes in psychological state as indexed by the 5D-ASC (altered states of consciousness) rating scales. This study suggests the involvement of serotonergic pathways in binocular rivalry and supports the previously proposed role of a brainstem oscillator in perceptual rivalry alternations and symptoms of psychosis.
Optimal, unsupervised learning in invariant object recognition
Publisher: MIT Press - Journals
Date: 05-1997
DOI: 10.1162/NECO.1997.9.4.883
Abstract: A means for establishing transformation-invariant representations of objects is proposed and analyzed, in which different views are associated on the basis of the temporal order of the presentation of these views, as well as their spatial similarity. Assuming knowledge of the distribution of presentation times, an optimal linear learning rule is derived. Simulations of a competitive network trained on a character recognition task are then used to highlight the success of this learning rule in relation to simple Hebbian learning and to show that the theory can give accurate quantitative predictions for the optimal parameters for such networks.
The prototype effect revisited: Evidence for an abstract feature model of face recognition
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 24-03-2008
DOI: 10.1167/8.3.20
Categorical face perception in fish: How a fish brain warps reality to dissociate “same” from “different”
Publisher: Wiley
Date: 29-05-2020
DOI: 10.1002/CNE.24947
Incidence of Hospitalization for Stroke in Queensland, Australia: Younger Adults at Risk
Publisher: Elsevier BV
Date: 06-2020
Complex, context-dependent decision strategies of archerfish, Toxotes chatareus
Publisher: Elsevier BV
Date: 12-2013
VO2peak and 24‐hour sleep, sedentary behavior, and physical activity in Australian truck drivers
Publisher: Wiley
Date: 11-05-2021
DOI: 10.1111/SMS.13965
Abstract: This study assessed cardiorespiratory fitness (CRF) and 24‐h sleep, sedentary behavior (SB), and physical activity (PA) in Australian truck drivers. Participants ( n = 37 men) attended clinic sessions for an exercise test to exhaustion to establish CRF and wore an accelerometer (Actigraph GT3X+) to estimate sleep, SB, and PA. Relative to normative values, CRF was “below percentile 25” in 51% of drivers (mean [SD] VO 2peak=30 .1 [7.6] mL.kg‐1.min‐1). Accelerometer data indicated that total vigorous‐intensity (3.5–4.5 min/day) and sustained moderate‐ to vigorous‐intensity PA ( min 0.5–1.6 bouts/day) were limited. The findings show there is a need to design and test PA interventions that can improve poor levels of CRF in truck drivers.
Effect of control order on steering a simulated underground coal shuttle car
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.APERGO.2012.07.007
Abstract: Most terrestrial vehicles are steered via a first-order control for vehicle heading, such as a conventional steering wheel. A joystick which provides second-order control of vehicle heading is used to steer some underground coal shuttle cars. A desktop virtual simulation of the situation was employed to compare the steering accuracy of 24 novice participants randomly assigned to either first-order or second-order joystick steering conditions. The average steering accuracy of participants assigned to the first-order joystick condition was superior, however there was considerable in idual variability and some participants assigned to the second-order steering condition were able to perform the task equally and successfully. Desktop virtual simulation may be a useful component of training and competency assessment for operators of these vehicles.
Linear models of simple cells: Correspondence to real cell responses and space spanning properties
Publisher: Brill
Date: 2001
DOI: 10.1163/156856801753253573
Abstract: Despite their limitations, linear filter models continue to be used to simulate the receptive field properties of cortical simple cells. For theoreticians interested in large scale models of visual cortex, a family of self-similar filters represents a convenient way in which to characterise simple cells in one basic model. This paper reviews research on the suitability of such models, and goes on to advance biologically motivated reasons for adopting a particular group of models in preference to all others. In particular, the paper describes why the Gabor model, so often used in network simulations, should be dropped in favour of a Cauchy model, both on the grounds of frequency response and mutual filter orthogonality.
Construct validation of a physical model colonoscopy simulator
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.GIE.2012.03.246
Abstract: Previous studies have demonstrated the construct validity of virtual reality colonoscopy simulators by showing that they can distinguish between users according to their level of endoscopic experience. Although physical model simulators are known to simulate looping more realistically than these devices, they lack published validation evidence. To assess the construct validity of a physical model simulator, the Kyoto Kagaku Colonoscope Training Model (Kyoto Kagaku Co. Ltd, Kyoto, Japan) and to determine its suitability for assessing the insertion skill of trainee colonoscopists. Validation study 21 experienced colonoscopists and 18 novices made 2 attempts at each of 4 standard cases on the Kyoto Kagaku physical model simulator, and we compared their performance on each case. A medical simulation center in a large tertiary hospital. Completion rates, times to cecum, and peak forces applied to the colon model. Compared with novices, experienced colonoscopists had significantly higher completion to cecum rates and shorter times to cecum for each of the 4 cases (all P < .005). For 2 cases, experienced colonoscopists also exerted significantly lower peak forces than did novices (both P = .01). Two of the model's 6 "standard cases" were not included in the study. The 4 cases included in the study have construct validity in that they can distinguish between the performance of experienced colonoscopists and novices, reproducing experienced/novice differences found in real colonoscopy. These cases can be used to validly assess the insertion skill of colonoscopy trainees.
Fixational eye movements during viewing of dynamic natural scenes
Publisher: Frontiers Media SA
Date: 2013
Express visuomotor responses reflect knowledge of both target location and conscious intent during reaches of different amplitudes
Publisher: Cold Spring Harbor Laboratory
Date: 06-11-2022
DOI: 10.1101/2022.11.06.515363
Abstract: When humans reach to visual targets, extremely rapid (~90 ms) bursts of activity can be observed on task-relevant proximal muscles. Such express visuomotor responses are inflexibly locked in time and space to the target and have been proposed to reflect rapid visuomotor transformations conveyed subcortically via the tecto-reticulo-spinal pathway. Previously, we showed that express visuomotor responses are sensitive to explicit cue-driven information about the target, suggesting that the express pathway can be modulated by cortical signals affording contextual pre-stimulus expectations. Here, we show that the express visuomotor system incorporates information about the veridical target-directed reaching metrics and contextual instructions during visuospatial tasks requiring different movement litudes. In one experiment, we recorded the activity from two shoulder muscles as participants reached toward targets that appeared at different distances. Longer hand-to-target distances led to larger and more prevalent express visuomotor responses than short-reach targets. This suggests that both the direction and distance of veridical hand-to-target reaches are encoded along the putative subcortical express pathway. In a second experiment, we modulated the movement litude by asking the participants to deliberately undershoot, overshoot, or stop (control) at the target. The overshoot and undershoot tasks impaired the generation of large and frequent express visuomotor responses, consistent with the inability of the express pathway to generate responses directed toward non-veridical targets (e.g. anti-reach tasks). Our findings appear to reflect strategic, cortically-driven modulation of the express visuomotor circuit to facilitate rapid and effective response initiation during target-directed actions. Express (~90 ms) arm muscle responses that are consistently tuned toward the location of visual stimuli suggest a subcortical contribution to target-directed visuomotor behaviour in humans, potentially via the tecto-reticulo-spinal pathway. This study shows that express muscle responses are modulated appropriately to reach targets at different distances, but generally suppressed when the task required non-veridical responses to overshoot/undershoot the real target. The data suggest that the tecto-reticulo-spinal pathway can be exploited strategically by the cerebral cortex to facilitate rapid initiation of effective responses during a visuospatial task.
A Species of Reef Fish that Uses Ultraviolet Patterns for Covert Face Recognition
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.CUB.2009.12.047
Abstract: The evolutionary and behavioral significance of an animal's color patterns remains poorly understood [1-4], not least, patterns that reflect ultraviolet (UV) light [5]. The current belief is that UV signals must be broad and bold to be detected because (1) they are prone to scattering in air and water, (2) when present, UV-sensitive cones are generally found in low numbers, and (3) long-wavelength-sensitive cones predominate in form vision in those species tested to date [6]. We report a study of two species of damselfish whose appearance differs only in the fine detail of UV-reflective facial patterns. We show that, contrary to expectations, the Ambon damselfish (Pomacentrus amboinensis) is able to use these patterns for species discrimination. We also reveal that the essential features of the patterns are contained in their shape rather than color. The results provide support for the hypothesis that UV is used by some fish as a high-fidelity "secret communication channel" hidden from predators [7, 8]. In more general terms, the findings help unravel the details of a language of color and pattern long since lost to our primate forebears, but which has been part of the world of many seeing organisms for millions of years.
Language as a Predictor of Motor Recovery: The Case for a More Global Approach to Stroke Rehabilitation
Publisher: SAGE Publications
Date: 13-02-2019
Abstract: Stroke is the third leading cause of death in the developed world and the primary cause of adult disability. The most common site of stroke is the middle cerebral artery (MCA), an artery that supplies a range of areas involved in both language and motor function. As a consequence, many stroke patients experience a combination of language and motor deficits. Indeed, those suffering from Broca’s aphasia have an 80% chance of also suffering hemiplegia. Despite the prevalence of multifaceted disability in patients, the current trend in both clinical trials and clinical practice is toward compartmentalization of dysfunction. In this article, we review evidence that aphasia and hemiplegia do not just coexist, but that they interact. We review a number of clinical reports describing how therapies for one type of deficit can improve recovery in the other and vice versa. We go on to describe how language deficits should be seen as a warning to clinicians that the patient is likely to experience motor impairment and slower motor recovery, aiding clinicians to optimize their choice of therapy. We explore these findings and offer a tentative link between language and arm function through their shared need for sequential action, which we term fluency. We propose that area BA44 (part of Broca’s area) acts as a hub for fluency in both movement and language, both in terms of production and comprehension.
Reducing the size of the human physiological blind spot through training
Publisher: Elsevier BV
Date: 08-2015
A competency framework for colonoscopy training derived from cognitive task analysis techniques and expert review
Publisher: Springer Science and Business Media LLC
Date: 12-2015
Object recognition in fish: accurate discrimination across novel views of an unfamiliar object category (human faces)
Publisher: Elsevier BV
Date: 11-2018
The role of visual and nonvisual feedback in a vehicle steering task
Publisher: American Psychological Association (APA)
Date: 2007
DOI: 10.1037/0096-1523.33.5.1127
Abstract: This article investigates vehicle steering control, focusing on the task of lane changing and the role of different sources of sensory feedback. Participants carried out 2 experiments in a fully instrumented, motion-based simulator. Despite the high level of realism afforded by the simulator, participants were unable to complete a lane change in the absence of visual feedback. When asked to produce the steering movements required to change lanes and turn a corner, participants produced remarkably similar behavior in each case, revealing a misconception of how a lane-change maneuver is normally executed. Finally, participants were asked to change lanes in a fixed-based simulator, in the presence of intermittent visual information. Normal steering behavior could be restored using brief but suitably timed exposure to visual information. The data suggest that vehicle steering control can be characterized as a series of unidirectional, open-loop steering movements, each punctuated by a brief visual update.
Reducing control selection errors associated with underground bolting equipment
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.APERGO.2009.11.008
Abstract: Selecting the incorrect control during the operation of underground bolting and drilling equipment causes serious injuries. Shape coding and the layout of dual control banks are two aspects of control design which require further examination. The aims of this research were: (i) to determine whether arbitrary shape coding was effective in reducing selection error rates in a virtual analogy of roof-bolting and (ii) to determine whether any advantages exist for mirror or place layouts for dual control situations in this situation. Two experiments were conducted to address these questions. No benefits of arbitrary shape coding were evident while control location remained constant. When control location was altered, shape coding did provide a significant reduction in selection error rate. No differences between mirror or place arrangements were detected and this question remains open.
Stability criteria for unsupervised temporal association networks
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2005
Related Organisations
Imperial College London
Location: United Kingdom of Great Britain and Northern Ireland
University Of Oxford
Location: United Kingdom of Great Britain and Northern Ireland
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