Sheila Gillard Crewther

The Contribution of Visual and Auditory Working Memory and Non-Verbal IQ to Motor Multisensory Processing in Elementary School Children

Publisher: MDPI AG

Date: 05-02-2023

DOI: 10.3390/BRAINSCI13020270

Abstract: Although cognitive abilities have been shown to facilitate multisensory processing in adults, the development of cognitive abilities such as working memory and intelligence, and their relationship to multisensory motor reaction times (MRTs), has not been well investigated in children. Thus, the aim of the current study was to explore the contribution of age-related cognitive abilities in elementary school-age children (n = 75) aged 5–10 years, to multisensory MRTs in response to auditory, visual, and audiovisual stimuli, and a visuomotor eye–hand co-ordination processing task. Cognitive performance was measured on classical working memory tasks such as forward and backward visual and auditory digit spans, and the Raven’s Coloured Progressive Matrices (RCPM test of nonverbal intelligence). Bayesian Analysis revealed decisive evidence for age-group differences across grades on visual digit span tasks and RCPM scores but not on auditory digit span tasks. The results also showed decisive evidence for the relationship between performance on more complex visually based tasks, such as difficult items of the RCPM and visual digit span, and multisensory MRT tasks. Bayesian regression analysis demonstrated that visual WM digit span tasks together with nonverbal IQ were the strongest unique predictors of multisensory processing. This suggests that the capacity of visual memory rather than auditory processing abilities becomes the most important cognitive predictor of multisensory MRTs, and potentially contributes to the expected age-related increase in cognitive abilities and multisensory motor processing.

The Influence of Light Wavelength on Human HPA Axis Rhythms: A Systematic Review

Publisher: MDPI AG

Date: 26-09-2023

DOI: 10.3390/LIFE13101968

Dyslexic children show altered temporal structure of the nonlinear VEP

Publisher: Cold Spring Harbor Laboratory

Date: 09-07-2019

DOI: 10.1101/697201

Abstract: The neural basis of dyslexia remains unresolved, despite many theories relating dyslexia to dysfunction in visual magnocellular and auditory temporal processing, cerebellar dysfunction, attentional deficits, as well as excessive neural noise. Recent research identifies perceptual speed as a common factor, integrating several of these systems. Optimal perceptual speed invokes transient attention as a necessary component, and change detection in gap paradigm tasks is impaired in those with dyslexia. This research has also identified an overall better change detection for targets presented in the upper compared with lower visual fields. Despite the magnocellular visual pathway being implicated in the aetiology of dyslexia over 30 years ago, objective physiological measures have been lacking. Thus, we employed nonlinear visual evoked potential (VEP) techniques which generate second order kernel terms specific for magno and parvocellular processing as a means to assessing the physiological status of poor readers (PR, n=12) compared with good readers (GR, n=16) selected from children with a mean age of 10yr. The first and second order Wiener kernels using multifocal VEP were recorded from a 4° foveal stimulus patch as well as for upper and lower visual field peripheral arcs. Foveal responses showed little difference between GR and PR for low contrast stimulation, except for the second slice of the second order kernel where lower peak litudes were recorded for PR vs GR. At high contrast, there was a trend to smaller first order kernel litudes for short latency peaks of the PR vs GR. In addition, there were significant latency differences for the first negativity in the first two slices of the second order kernel. In terms of peripheral stimulation, lower visual field response litudes were larger compared with upper visual field responses, for both PR and GR. A trend to larger second/first order ratio for magnocellularly driven responses suggests the possibility of lesser neural efficiency in the periphery for the PR compared with the GR. Stronger lower field peripheral response may relate to better upper visual field change detection performance when target visibility is controlled through flicking masks. In conclusion, early cortical magnocellular processing at low contrast was normal in those with dyslexia, while cortical activity related to parvocellular afferents was reduced. In addition, the study demonstrated a physiological basis for upper versus lower visual field differences related to magnocellular function.

Visual mapping on the brain - caveats for multifocal fMRI

Publisher: Cold Spring Harbor Laboratory

Date: 20-06-2019

DOI: 10.1101/676023

Abstract: While multifocal electroretinography has become a standard ophthalmological technique, its use in cortical neuroimaging has been lesser. Vanni et al. (2005) presented the first exploration of the multifocal visual mapping methodology with fMRI. This commentary confirms the utility of this method, but also presents empirical results which suggest caveats for the use of the technique. In the current study rapid multifocal fMRI was established using m-sequence pseudo-random binary stimuli applied to visual field mapping in six young adults with normal vision. Nine contiguous regions of visual field – two rings of 4 patches with a central patch, areas scaled for cortical magnification, were pseudo-randomly stimulated, with patterned or grey images. The decorrelation of stimulus patches allowed all 256 volumes to be used for the analysis of each of the nine stimulus areas. Strong localized activation was observed for each of the four peripheral regions with the location of the activation conforming to the expected visual field retinotopy. The inner regions, including the foveal patch, did not significantly activate. We propose, on the basis of a simple correlational model of simulated eye movements, that the loss of signal is due to gaze instability. Thus, while the rapid multifocal method can be successfully applied to fMRI, the results appear quite sensitive to eye movements, the effects of which may have been overlooked by smoothing evoked responses to achieve a retinotopic map.

Kinematic Studies of the Go/No-Go Task as a Dynamic Sensorimotor Inhibition Task for Assessment of Motor and Executive Function in Stroke Patients: An Exploratory Study in a Neurotypical Sample

Publisher: MDPI AG

Date: 19-11-2022

DOI: 10.3390/BRAINSCI12111581

Abstract: Inhibition of reaching and grasping actions as an element of cognitive control and executive function is a vital component of sensorimotor behaviour that is often impaired in patients who have lost sensorimotor function following a stroke. To date, there are few kinematic studies detailing the fine spatial and temporal upper limb movements associated with the millisecond temporal trajectory of correct and incorrect responses to visually driven Go/No-Go reaching and grasping tasks. Therefore, we aimed to refine the behavioural measurement of correct and incorrect inhibitory motor responses in a Go/No-Go task for future quantification and personalized rehabilitation in older populations and those with acquired motor disorders, such as stroke. An exploratory study mapping the kinematic profiles of hand movements in neurotypical participants utilizing such a task was conducted using high-speed biological motion capture cameras, revealing both within and between subject differences in a s le of healthy participants. These kinematic profiles and differences are discussed in the context of better assessment of sensorimotor function impairment in stroke survivors.

Visual Processing During the Interictal Period Between Migraines: A Meta-Analysis

Publisher: Springer Science and Business Media LLC

Date: 17-09-2022

DOI: 10.1007/S11065-022-09562-3

Abstract: Migraine is a poorly understood neurological disorder and a leading cause of disability in young adults, particularly women. Migraines are characterized by recurring episodes of severe pulsating unilateral headache and usually visual symptoms. Currently there is some disagreement in the electrophysiological literature regarding the universality of all migraineurs exhibiting physiological visual impairments also during interictal periods (i.e., the symptom free period between migraines). Thus, this meta-analysis investigated the evidence for altered visual function as measured electrophysiologically via pattern-reversal visual evoked potential (VEP) litudes and habituation in adult migraineurs with or without visual aura and controls in the interictal period. Twenty-three studies were selected for random effects meta-analysis which demonstrated slightly diminished VEP litudes in the early fast conducting P100 component but not in N135, and substantially reduced habituation in the P100 and the N135 in migraineurs with and without visual aura symptoms compared to controls. No statistical differences were found between migraineurs with and without aura, possibly due to inadequate studies. Overall, insufficient published data and substantial heterogeneity between studies was observed for all latency components of pattern-reversal VEP, highlighting the need for further electrophysiological experimentation and more targeted temporal analysis of visual function, in episodic migraineurs.

A Role for Visual Memory in Vocabulary Development: A Systematic Review and Meta-Analysis.

Publisher: Springer Science and Business Media LLC

Date: 22-09-2022

DOI: 10.1007/S11065-022-09561-4

Abstract: Although attention and early associative learning in preverbal children is predominantly driven by rapid eye-movements in response to moving visual stimuli and sounds/words (e.g., associating the word "bottle" with the object), the literature examining the role of visual attention and memory in ongoing vocabulary development across childhood is limited. Thus, this systematic review and meta-analysis examined the association between visual memory and vocabulary development, including moderators such as age and task selection, in neurotypical children aged 2-to-12 years, from the brain-based perspective of cognitive neuroscience. Visual memory tasks were classified according to the visual characteristics of the stimuli and the neural networks known to preferentially process such information, including consideration of the distinction between the ventral visual stream (processing more static visuo-perceptual details, such as form or colour) and the more dynamic dorsal visual stream (processing spatial temporal action-driven information). Final classifications included spatio-temporal span tasks, visuo-perceptual or spatial concurrent array tasks, and executive judgment tasks. Visuo-perceptual concurrent array tasks, reliant on ventral stream processing, were moderately associated with vocabulary, while tasks measuring spatio-temporal spans, associated with dorsal stream processing, and executive judgment tasks (central executive), showed only weak correlations with vocabulary. These findings have important implications for health professionals and researchers interested in language, as they advocate for the development of more targeted language learning interventions that include specific and relevant aspects of visual processing and memory, such as ventral stream visuo-perceptual details (i.e., shape or colour).

Metacontrast masking as a measure of change detection: Children with poor reading fluency show impaired change detection for both letters and shapes

Publisher: Cold Spring Harbor Laboratory

Date: 10-07-2019

DOI: 10.1101/697870

Abstract: Developmental dyslexia, a specific learning difficulty in reading, manifests as effortful decoding of words and as such is commonly associated with reduced phonemic awareness. However, its underlying cause remains elusive, with magnocellular visual processing, temporal auditory processing, visual attentional deficits and cerebellar dysfunction all gaining some traction. More recent theories have concerned visual attention span, measuring the parallel attentive capacity of the sensory visual system. However the VA span task as implemented requires reports, both conscious recall and recognition of letters, that activate many cortical areas beyond sensory visual cortex. Change detection, in contrast, does not require the conscious recognition of items, but simply awareness that the stimulus has changed, or not, again testing visual attention in a parallel fashion, but avoiding the complications of higher order cognitive processes. Thus, we investigated change detection in 33 good and poor readers with ages of around 10 yr, using a gap paradigm. Groups of 4 letters or 4 shapes were presented for a fixed time (0.7 s), followed after a 0.25 s gap, by a second similar group, each item surrounded by an annular frame filled with dynamic random noise of variable contrast. Detection performance was manipulated by varying the contrast of these meta-contrast mask frames, yielding a threshold contrast of the frames at which participants could just detect change. In two separate experiments, letters and rectangular shapes were used as target items, in order to test whether previous findings of superior change detection in good compared with poor readers was a result of greater automaticity in letter recognition of the good readers. The results indicate that the good readers were able to detect change at higher levels of masking distraction for both the letter and shape targets, indicating that this difference is not specifically related to to the training of graphemic or lexical information but more likely reflects a difference in alerting or pre-recognition stages of visual processing. Together, the results provide further support of the notion that there is a low level attentional performance difference between dyslexic and normal reading children. Thus, the results further bring transient spatial attention directly into the spotlight as an ability critical for learning to read.

Escalating Bi-Directional Feedback Loops between Proinflammatory Microglia and Mitochondria in Ageing and Post-Diagnosis of Parkinson’s Disease

Publisher: MDPI AG

Date: 18-05-2023

DOI: 10.3390/ANTIOX12051117

Abstract: Parkinson’s disease (PD) is a chronic and progressive age-related neurodegenerative disease affecting up to 3% of the global population over 65 years of age. Currently, the underlying physiological aetiology of PD is unknown. However, the diagnosed disorder shares many common non-motor symptoms associated with ageing-related neurodegenerative disease progression, such as neuroinflammation, microglial activation, neuronal mitochondrial impairment, and chronic autonomic nervous system dysfunction. Clinical PD has been linked to many interrelated biological and molecular processes, such as escalating proinflammatory immune responses, mitochondrial impairment, lower adenosine triphosphate (ATP) availability, increasing release of neurotoxic reactive oxygen species (ROS), impaired blood brain barrier integrity, chronic activation of microglia, and damage to dopaminergic neurons consistently associated with motor and cognitive decline. Prodromal PD has also been associated with orthostatic hypotension and many other age-related impairments, such as sleep disruption, impaired gut microbiome, and constipation. Thus, this review aimed to present evidence linking mitochondrial dysfunction, including elevated oxidative stress, ROS, and impaired cellular energy production, with the overactivation and escalation of a microglial-mediated proinflammatory immune response as naturally occurring and damaging interlinked bidirectional and self-perpetuating cycles that share common pathological processes in ageing and PD. We propose that both chronic inflammation, microglial activation, and neuronal mitochondrial impairment should be considered as concurrently influencing each other along a continuum rather than as separate and isolated linear metabolic events that affect specific aspects of neural processing and brain function.

Different effects of trait and state anxiety on global-local visual processing following acute stress

Publisher: Babes-Bolyai University

Date: 16-09-2019

DOI: 10.24193/CBB.2019.23.09

Flash Electroretinography as a Measure of Retinal Function in Myopia and Hyperopia: A Systematic Review

Publisher: MDPI AG

Date: 27-02-2023

DOI: 10.3390/VISION7010015

Abstract: Refractive errors (myopia and hyperopia) are the most common visual disorders and are severe risk factors for secondary ocular pathologies. The development of refractive errors has been shown to be associated with changes in ocular axial length, suggested to be induced by outer retinal elements. Thus, the present study systematically reviewed the literature examining retinal function as assessed using global flash electroretinograms (gfERGs) in human clinical refractive error populations. Electronic database searching via Medline, PubMed, Web of Science, Embase, Psych INFO, and CINAHL retrieved 981 unique records (last searched on the 29 May 2022). Single case studies, s les with ocular comorbidities, drug trials, and reviews were excluded. Demographic characteristics, refractive state, gfERG protocol details, and waveform characteristics were extracted for the eight studies that met the inclusion criteria for the review and were judged to have acceptable risk of bias using the OHAT tool (total N = 552 participants age 7 to 50). Study synthesis suggests that myopia in humans involves attenuation of gfERG photoreceptor (a-wave) and bipolar cell (b-wave) function, consistent with the animal literature. Meaningful interpretation of the overall findings for hyperopia was limited by inconsistent reporting, highlighting the need for future studies to report key aspects of gfERG research design and outcomes more consistently for myopic and hyperopic refractive errors.

Visual Motor Reaction Times Predict Receptive and Expressive Language Development in Early School-Age Children

Publisher: MDPI AG

Date: 19-06-2023

DOI: 10.3390/BRAINSCI13060965

Abstract: Proficiency of multisensory processing and motor skill are often associated with early cognitive, social, and language development. However, little research exists regarding the relationship between multisensory motor reaction times (MRTs) to auditory, visual and audiovisual stimuli, and classical measures of receptive language and expressive vocabulary development in school-age children. Thus, this study aimed to examine the concurrent development of performance in classical tests of receptive (Peabody Picture Vocabulary Test abbreviated as PPVT) and expressive vocabulary (Expressive Vocabulary Test abbreviated as EVT), nonverbal intelligence (NVIQ) (determined with the aid of Raven’s Colored Progressive Matrices abbreviated as RCPM), speed of visual–verbal processing in the Rapid Automatic Naming (RAN) test, Eye–Hand Co-ordination (EHC) in the SLURP task, and multisensory MRTs, in children (n = 75), aged between 5 and 10 years. Bayesian statistical analysis showed evidence for age group differences in EVT performance, while PPVT was only different for the youngest group of children aged 5–6, supporting different developmental trajectories in vocabulary acquisition. Bayesian correlations revealed evidence for associations between age, NVIQ, and vocabulary measures, with decisive evidence and a higher correlation (r = 0.57 to 0.68) between EVT, MRT tasks, and EHC visuomotor processing. This was further supported by regression analyses indicating that EVT performance was the strongest unique predictor of multisensory MRTs, EHC, and RAN time. Additionally, visual MRTs were found to predict both receptive and expressive vocabulary. The findings of the study have important implications as accessible school-based assessments of the concurrent development of NVIQ, language, and multisensory processing and hence as rapid and timely measures of developmental and neurodevelopmental status.

La Trobe University

Location: Australia

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California Institute Of Technology

Location: United States of America

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