ORCID Profile
0000-0002-0544-6533
Current Organisation
Linköping University
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Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: Cold Spring Harbor Laboratory
Date: 10-10-2023
Publisher: Center for Open Science
Date: 28-04-2023
Abstract: In the present original online study, we examined a largely neglected area of research in psychology: grief, its bodily sensations, and social touch as means of consolation in times of grief.
Publisher: IEEE
Date: 07-2019
Publisher: American Physiological Society
Date: 03-2016
Abstract: Neurophysiological studies in primates have found that direction-sensitive neurons in the primary somatosensory cortex (SI) generally increase their response rate with increasing speed of object motion across the skin and show little evidence of speed tuning. We employed psychophysics to determine whether human perception of motion direction could be explained by features of such neurons and whether evidence can be found for a speed-tuned process. After adaptation to motion across the skin, a subsequently presented dynamic test stimulus yields an impression of motion in the opposite direction. We measured the strength of this tactile motion aftereffect (tMAE) induced with different combinations of adapting and test speeds. Distal-to-proximal or proximal-to-distal adapting motion was applied to participants' index fingers using a tactile array, after which participants reported the perceived direction of a bidirectional test stimulus. An intensive code for speed, like that observed in SI neurons, predicts greater adaptation (and a stronger tMAE) the faster the adapting speed, regardless of the test speed. In contrast, speed tuning of direction-sensitive neurons predicts the greatest tMAE when the adapting and test stimuli have matching speeds. We found that the strength of the tMAE increased monotonically with adapting speed, regardless of the test speed, showing no evidence of speed tuning. Our data are consistent with neurophysiological findings that suggest an intensive code for speed along the motion processing pathways comprising neurons sensitive both to speed and direction of motion.
Publisher: University of Western Sydney
Date: 2016
Publisher: Public Library of Science (PLoS)
Date: 24-09-2012
Publisher: Cold Spring Harbor Laboratory
Date: 09-03-2019
DOI: 10.1101/570929
Abstract: The established view is that vibrotactile stimuli evoke two qualitatively distinctive cutaneous sensations, flutter (frequencies 60 Hz) and vibratory hum (frequencies 60 Hz), subserved by two distinct receptor types (Meissner’s and Pacinian corpuscle, respectively) which may engage different neural processing pathways or channels and fulfill quite different biological roles. In psychological and physiological literature those two systems have been labelled as Pacinian and non-Pacinian channels. However, we present evidence that low-frequency spike trains in Pacinian afferents can readily induce a vibratory percept with the same low frequency attributes as sinusoidal stimuli of the same frequency thus demonstrating a universal frequency decoding system. We achieved this using brief low- litude pulsatile mechanical stimuli to selectively activate Pacinian afferents. This indicates that spiking pattern, regardless of receptor type, determines vibrotactile frequency perception. This mechanism may underlie the constancy of vibrotactile frequency perception across different skin regions innervated by distinct afferent types.
Publisher: IEEE
Date: 07-2017
Publisher: Springer Berlin Heidelberg
Date: 2014
Publisher: Cold Spring Harbor Laboratory
Date: 25-07-2023
DOI: 10.1101/2023.07.22.549516
Abstract: Interpersonal touch is an important part of our social and emotional interactions. How these physical, skin-to-skin touch expressions are processed in the peripheral nervous system is not well understood. From single-unit microneurography recordings in humans, we evaluated the capacity of six subtypes of cutaneous afferents to differentiate perceptually distinct social touch expressions. By leveraging conventional statistical analyses and classification analyses using convolutional neural networks and support vector machines, we found that single units of multiple Aβ subtypes, especially slowly adapting type II (SA-II) and fast adapting hair follicle afferents (HFA), can reliably differentiate the skin contact of those expressions at accuracies similar to those perceptually. Rapidly adapting field (Field) afferents exhibit lower accuracies, whereas C-tactile (CT), fast adapting Pacinian corpuscles (FA-II), and muscle spindle (MS) afferents can barely differentiate the expressions, despite responding to the stimuli. We then identified the most informative firing patterns of SA-II and HFA afferents’ spike trains, which indicate that an average duration of 3-4 s of firing provides sufficient discriminative information. Those two subtypes also exhibit robust tolerance to shifts in spike-timing of up to 10 ms. A greater shift in spike-timing, however, drastically compromises an afferent’s discrimination capacity, and can change a firing pattern’s envelope to resemble that of another expression. Altogether, the findings indicate that SA-II and HFA afferents differentiate the skin contact of social touch at time scales relevant for such interactions, which is 1-2 orders of magnitude longer than those relevant for discriminating non-social touch inputs.
Publisher: IEEE
Date: 07-2019
Publisher: Cold Spring Harbor Laboratory
Date: 07-08-2020
DOI: 10.1101/2020.08.06.20169599
Abstract: The mortality of patients admitted to the intensive care unit (ICU) with COVID-19 is unclear due to variable censoring and substantial proportions of undischarged patients at follow-up. Nationwide data have not been previously reported. We studied the outcomes of Swedish patients at 30 days after ICU admission. We conducted a registry-based cohort study of all adult patients admitted to Swedish ICUs from 6 March-6 May, 2020 with laboratory confirmed COVID-19 disease and complete 30-day follow-up. Data including baseline characteristics, comorbidities, intensive care treatments, organ failures and outcomes were collected. The primary outcome was 30-day all-cause mortality. A multivariable model was used to determine the independent association between potential predictor variables and the primary outcome. A total of 1563 patients were identified. Median ICU length of stay was 12 (5-21) days, and fifteen patients remained in ICU at the time of follow-up. Median age was 61 (52-69), median Simplified Acute Physiology Score III (SAPS III) was 53 (46-59), and 66·8% had at least one comorbidity. Median PaO 2 /FiO 2 on admission was 97·5 (75·0-140·6) mmHg, 74·7% suffered from moderate to severe acute respiratory distress syndrome (ARDS). The 30-day all-cause mortality was 26·7%. The majority of deaths occurred during ICU admission. Age, male sex (adjusted odds ratio [aOR] 1·5 [1·1-2·1]), SAPS III score (aOR 1·3 [1·2-1·4]), severe ARDS (aOR 3·1 [2·0-4·8], specific COVID-19 pharmacotherapy (aOR 1·4 [1·0-1·9]), and CRRT (aOR 2·2 [1·6-3·0]), were associated with increased mortality. With the exception of chronic lung disease, the presence of comorbidities was not independently associated with mortality. Thirty-day mortality rate in COVID-19 patients admitted to Swedish intensive care units is generally lower than previously reported. Mortality appears to be driven by age, baseline disease severity, the degree of organ failure and ICU treatment, rather than preexisting comorbidities. Region Östergötland County Council and Linköping University number 30320008. In previous studies reporting outcomes for COVID-19 patients admitted to intensive care units (ICUs), none reported 30-day mortality rates, many were censored after short observation periods, and most had substantial proportions of undischarged patients at the time of follow-up. Incomplete data may cause bias in reported mortality rates. Further, national data on critically ill patients have not been previously published. Our study provides complete 30-day follow up in a nationwide population of 1563 unselected patients admitted to intensive care units in Sweden. All but 15 patients had been discharged from ICU at follow-up thus the study also provides an accurate reflection of ICU mortality. We also provide age-stratified mortality rates and information on ICU treatment and outcomes. This cohort also differs from previous studies in so far as directed antiviral therapy for COVID-19 disease was infrequently used. Adjusted risk estimates for the effect of baseline factors, ICU complications and treatment demonstrate that age, the severity of respiratory failure and need for continuous renal replacement therapy were the most important risk factors for death. Mortality rates of COVID-19 patients in Swedish ICUs are lower than those previously reported, despite the high incidence of comorbidities, an ageing population and a high proportion of patients with severe ARDS. Directed antiviral pharmacotherapy was given only to a minority of patients suggesting that survival from COVID-19 in ICU is achievable with good supportive care. Our analysis also suggests that unaccounted factors eg. process and organizational, may be important in determining the outcome of critically ill patients with COVID-19. Our results may be of interest since Sweden has a very limited number of ICU beds and has adopted a unique response to the pandemic compared to other countries. Despite limited numbers of ICU beds per capita, Sweden was able to increase its ICU capacity during the first 2 months of the COVID-19 pandemic and provide essential care to the critically ill with encouraging results.
Publisher: SAGE Publications
Date: 09-08-2022
DOI: 10.1177/09567976211059801
Abstract: Touch is a powerful communication tool, but we have a limited understanding of the role played by particular physical features of interpersonal touch communication. In this study, adults living in Sweden performed a task in which messages (attention, love, happiness, calming, sadness, and gratitude) were conveyed by a sender touching the forearm of a receiver, who interpreted the messages. Two experiments ( N = 32, N = 20) showed that within close relationships, receivers could identify the intuitive touch expressions of the senders, and we characterized the physical features of the touches associated with successful communication. Facial expressions measured with electromyography varied by message but were uncorrelated with communication performance. We developed standardized touch expressions and quantified the physical features with 3D hand tracking. In two further experiments ( N = 20, N = 16), these standardized expressions were conveyed by trained senders and were readily understood by strangers unacquainted with the senders. Thus, the possibility emerges of a standardized, intuitively understood language of social touch.
Publisher: Center for Open Science
Date: 09-08-2017
Abstract: Introduction: While the directionality of tactile motion processing has been studied extensively, tactile speed processing and its relationship to direction is little-researched and poorly understood. We investigated this relationship in humans using the ‘tactile speed aftereffect’ (tSAE), in which the speed of motion appears slower following prolonged exposure to a moving surface. Method: We used psychophysical methods to test whether the tSAE is direction sensitive. After adapting to a ridged moving surface with one hand, participants compared the speed of test stimuli on the adapted and unadapted hands. We varied the direction of the adapting stimulus relative to the test stimulus. Results: Perceived speed of the surface moving at 81mm/s was reduced by about 30% regardless of the direction of the adapting stimulus (when adapted in the same direction, Mean reduction = 23mm/s, SD=11 with opposite direction, Mean reduction = 26mm/s, SD=9). In addition to a large reduction in perceived speed due to adaptation, we also report that this effect is not direction sensitive. Conclusions: Tactile motion is susceptible to speed adaptation. This result complements previous reports of reliable direction aftereffects when using a dynamic test stimulus as together they describe how perception of a moving stimulus in touch depends on the immediate history of stimulation. Given that the tSAE is not direction sensitive, we argue that peripheral adaptation does not explain it, because primary afferents are direction sensitive with friction-creating stimuli like ours (thus motion in their preferred direction should result in greater adaptation, and if perceived speed were critically dependent on these afferents’ response intensity, the tSAE should be direction sensitive). The adaptation that reduces perceived speed therefore seems to be of central origin.
Publisher: Informa UK Limited
Date: 07-2012
Publisher: Wiley
Date: 18-12-2019
DOI: 10.1002/BRB3.1184
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 25-07-2007
DOI: 10.1167/7.5.9
Publisher: American Physiological Society
Date: 03-2016
Abstract: After prolonged exposure to a surface moving across the skin, this felt movement appears slower, a phenomenon known as the tactile speed aftereffect (tSAE). We asked which feature of the adapting motion drives the tSAE: speed, the spacing between texture elements, or the frequency with which they cross the skin. After adapting to a ridged moving surface with one hand, participants compared the speed of test stimuli on adapted and unadapted hands. We used surfaces with different spatial periods (SPs 3, 6, 12 mm) that produced adapting motion with different combinations of adapting speed (20, 40, 80 mm/s) and temporal frequency (TF 3.4, 6.7, 13.4 ridges/s). The primary determinant of tSAE magnitude was speed of the adapting motion, not SP or TF. This suggests that adaptation occurs centrally, after speed has been computed from SP and TF, and/or that it reflects a speed cue independent of those features in the first place (e.g., indentation force). In a second experiment, we investigated the properties of the neural code for speed. Speed tuning predicts that adaptation should be greatest for speeds at or near the adapting speed. However, the tSAE was always stronger when the adapting stimulus was faster (242 mm/s) than the test (30–143 mm/s) compared with when the adapting and test speeds were matched. These results give no indication of speed tuning and instead suggest that adaptation occurs at a level where an intensive code dominates. In an intensive code, the faster the stimulus, the more the neurons fire.
Publisher: IEEE
Date: 06-07-2021
Publisher: IEEE
Date: 07-2019
Publisher: eLife Sciences Publications, Ltd
Date: 06-08-2019
DOI: 10.7554/ELIFE.46510
Abstract: The established view is that vibrotactile stimuli evoke two qualitatively distinctive cutaneous sensations, flutter (frequencies 60 Hz) and vibratory hum (frequencies 60 Hz), subserved by two distinct receptor types (Meissner’s and Pacinian corpuscle, respectively), which may engage different neural processing pathways or channels and fulfil quite different biological roles. In psychological and physiological literature, those two systems have been labelled as Pacinian and non-Pacinian channels. However, we present evidence that low-frequency spike trains in Pacinian afferents can readily induce a vibratory percept with the same low frequency attributes as sinusoidal stimuli of the same frequency, thus demonstrating a universal frequency decoding system. We achieved this using brief low- litude pulsatile mechanical stimuli to selectively activate Pacinian afferents. This indicates that spiking pattern, regardless of receptor type, determines vibrotactile frequency perception. This mechanism may underlie the constancy of vibrotactile frequency perception across different skin regions innervated by distinct afferent types.
Publisher: Center for Open Science
Date: 27-10-2021
Abstract: Touch is a powerful communication tool, but we have a limited understanding of the role played by particular physical features of interpersonal touch communication. In this study, adults living in Sweden performed a task in which messages (attention, love, happiness, calming, sadness and gratitude) were conveyed by a sender touching the forearm of a receiver, who interpreted the messages. Two experiments (n=32, n=20) showed that within close relationships, receivers could identify the intuitive touch expressions of the senders, and we characterized the physical features of the touches associated with successful communication. Facial expressions measured with EMG varied by message, but were uncorrelated with communication performance. We developed standardized touch expressions and quantified the physical features with 3D hand-tracking. In two further experiments (n=20, n=16), these were conveyed by trained senders and were readily understood by naïve strangers. Thus, the possibility emerges of a standardized, intuitively understood language of social touch.
Publisher: Springer Science and Business Media LLC
Date: 03-10-2017
Publisher: Oxford University Press (OUP)
Date: 27-12-2021
Abstract: Patients with bi-allelic loss of function mutations in the voltage-gated sodium channel Nav1.7 present with congenital insensitivity to pain (CIP), whilst low threshold mechanosensation is reportedly normal. Using psychophysics (n = 6 CIP participants and n = 86 healthy controls) and facial electromyography (n = 3 CIP participants and n = 8 healthy controls), we found that these patients also have abnormalities in the encoding of affective touch, which is mediated by the specialized afferents C-low threshold mechanoreceptors (C-LTMRs). In the mouse, we found that C-LTMRs express high levels of Nav1.7. Genetic loss or selective pharmacological inhibition of Nav1.7 in C-LTMRs resulted in a significant reduction in the total sodium current density, an increased mechanical threshold and reduced sensitivity to non-noxious cooling. The behavioural consequence of loss of Nav1.7 in C-LTMRs in mice was an elevation in the von Frey mechanical threshold and less sensitivity to cooling on a thermal gradient. Nav1.7 is therefore not only essential for normal pain perception but also for normal C-LTMR function, cool sensitivity and affective touch.
Publisher: Center for Open Science
Date: 08-02-2021
Abstract: Ageing is accompanied by a steady decline in touch sensitivity and acuity. Conversely, pleasant touch, such as experienced during a caress, is even more pleasant in old age. There are many physiological changes that might explain these perceptual changes, but researchers have not yet identified any specific mechanisms. Here, we review both the perceptual and structural changes to the touch system that are associated with ageing. The structural changes include reduced elasticity of the skin in older people, as well as reduced numbers and altered morphology of skin tactile receptors. Effects of ageing on the peripheral and central nervous systems include demyelination, which affects the timing of neural signals, as well as reduced numbers of peripheral nerve fibres. The ageing brain also undergoes complex changes in blood flow, metabolism, plasticity, neurotransmitter function, and, for touch, the body map in primary somatosensory cortex. Although several studies have attempted to find a direct link between perceptual and structural changes, this has proved surprisingly elusive. We also highlight the need for more evidence regarding age-related changes in peripheral nerve function in the hairy skin, as well as the social and emotional aspects of touch.
Start Date: 2021
End Date: 2024
Funder: Swedish Research Council
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End Date: End date not available
Funder: Australian Association of Gerontology
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