scholarly journals The biology of skin wetness perception and its implications in manual function and for reproducing complex somatosensory signals in neuroprosthetics

2017 ◽  
Vol 117 (4) ◽  
pp. 1761-1775 ◽  
Author(s):  
Davide Filingeri ◽  
Rochelle Ackerley
Keyword(s):  
Precision Grip ◽  
Significant Advance ◽  
Body Parts ◽  
Dexterous Manipulation ◽  
Somatosensory Cortices ◽  
Skin Cooling ◽  
Rapid Changes ◽  
Skin Wetness ◽  
Insula Cortex ◽  
Sensory Feedback In Prosthetics

Our perception of skin wetness is generated readily, yet humans have no known receptor (hygroreceptor) to signal this directly. It is easy to imagine the sensation of water running over our hands or the feel of rain on our skin. The synthetic sensation of wetness is thought to be produced from a combination of specific skin thermal and tactile inputs, registered through thermoreceptors and mechanoreceptors, respectively. The present review explores how thermal and tactile afference from the periphery can generate the percept of wetness centrally. We propose that the main signals include information about skin cooling, signaled primarily by thinly myelinated thermoreceptors, and rapid changes in touch, through fast-conducting, myelinated mechanoreceptors. Potential central sites for integration of these signals, and thus the perception of skin wetness, include the primary and secondary somatosensory cortices and the insula cortex. The interactions underlying these processes can also be modeled to aid in understanding and engineering the mechanisms. Furthermore, we discuss the role that sensing wetness could play in precision grip and the dexterous manipulation of objects. We expand on these lines of inquiry to the application of the knowledge in designing and creating skin sensory feedback in prosthetics. The addition of real-time, complex sensory signals would mark a significant advance in the use and incorporation of prosthetic body parts for amputees in everyday life.

Evidence for the involvement of peripheral cold-sensitive TRPM8 channels in human cutaneous hygrosensation

2020 ◽  
Vol 318 (3) ◽  
pp. R579-R589 ◽  
Author(s):  
Oliver Typolt ◽  
Davide Filingeri
Keyword(s):  
Human Skin ◽  
Chemical Activation ◽  
The Body ◽  
Cold Sensitivity ◽  
Trpm8 Channel ◽  
Body Regions ◽  
Skin Cooling ◽  
Cold Sensitive ◽  
Skin Wetness

In contrast to other species, humans are believed to lack hygroreceptors for sensing skin wetness. Yet, the molecular basis of human hygrosensation is currently unknown, and it remains unclear whether we possess a receptor-mediated sensing mechanism for skin wetness. The aim of this study was to assess the role of the cutaneous cold-sensitive transient receptor potential melastatin-8 (TRPM8) channel as a molecular mediator of human hygrosensation. To this end, we exploited both the thermal and chemical activation of TRPM8-expressing cutaneous Aδ cold thermoreceptors, and we assessed wetness sensing in healthy young men in response to 1) dry skin cooling in the TRPM8 range of thermosensitivity and 2) application of the TRPM8 agonist menthol. Our results indicate that 1) independently of contact with moisture, a cold-dry stimulus in the TRPM8 range of activation induced wetness perceptions across 12 different body regions and those wetness perceptions varied across the body following regional differences in cold sensitivity; and 2) independently of skin cooling, menthol-induced stimulation of TRPM8 triggered wetness perceptions that were greater than those induced by physical dry cooling and by contact with an aqueous cream containing actual moisture. For the first time, we show that the cutaneous cold-sensing TRPM8 channel plays the dual role of cold and wetness sensor in human skin and that this ion channel is a peripheral mediator of human skin wetness perception.

scholarly journals The role of decreasing contact temperatures and skin cooling in the perception of skin wetness

2013 ◽  
Vol 551 ◽  
pp. 65-69 ◽  
Author(s):  
Davide Filingeri ◽  
Bernard Redortier ◽  
Simon Hodder ◽  
George Havenith
Keyword(s):  
Skin Cooling ◽  
Skin Wetness

scholarly journals Pose Estimation of Swimming Fish Using NACA Airfoil Model for Collective Behavior Analysis

2021 ◽  
Vol 33 (3) ◽  
pp. 547-555
Author(s):  
Hitoshi Habe ◽  
Yoshiki Takeuchi ◽  
Kei Terayama ◽  
Masa-aki Sakagami ◽  
◽  
...  
Keyword(s):  
Behavior Analysis ◽  
Pose Estimation ◽  
Collective Behavior ◽  
Estimation Method ◽  
The State ◽  
Video Data ◽  
Body Parts ◽  
Fish Schools ◽  
Dynamic Variations ◽  
Rapid Changes

We propose a pose estimation method using a National Advisory Committee for Aeronautics (NACA) airfoil model for fish schools. This method allows one to understand the state in which fish are swimming based on their posture and dynamic variations. Moreover, their collective behavior can be understood based on their posture changes. Therefore, fish pose is a crucial indicator for collective behavior analysis. We use the NACA model to represent the fish posture; this enables more accurate tracking and movement prediction owing to the capability of the model in describing posture dynamics. To fit the model to video data, we first adopt the DeepLabCut toolbox to detect body parts (i.e., head, center, and tail fin) in an image sequence. Subsequently, we apply a particle filter to fit a set of parameters from the NACA model. The results from DeepLabCut, i.e., three points on a fish body, are used to adjust the components of the state vector. This enables more reliable estimation results to be obtained when the speed and direction of the fish change abruptly. Experimental results using both simulation data and real video data demonstrate that the proposed method provides good results, including when rapid changes occur in the swimming direction.

scholarly journals Case Studies in Neuroscience: Sensations elicited and discrimination ability from nerve cuff stimulation in an amputee over time

2018 ◽  
Vol 120 (1) ◽  
pp. 291-295 ◽  
Author(s):  
Rochelle Ackerley ◽  
Helena Backlund Wasling ◽  
Max Ortiz-Catalan ◽  
Rickard Brånemark ◽  
Johan Wessberg
Keyword(s):  
Electrical Stimulation ◽  
Peripheral Nerve ◽  
Sensory Feedback ◽  
Precision Grip ◽  
Just Noticeable Difference ◽  
Body Parts ◽  
Discrimination Ability ◽  
Nerve Cuff ◽  
Stimulation Of

The present case study details sensations elicited by electrical stimulation of peripheral nerve axons using an implanted nerve cuff electrode, in a participant with a transhumeral amputation. The participant uses an osseointegrated electromechanical interface, which enables skeletal attachment of the prosthesis and long-term, stable, bidirectional communication between the implanted electrodes and prosthetic arm. We focused on evoking somatosensory percepts, where we tracked and quantified the evolution of perceived sensations in the missing hand, which were evoked from electrical stimulation of the nerve, for over 2 yr. These sensations included small, pointlike areas of either vibration or pushing, to larger sensations over wider areas, indicating the recruitment of a few and many afferents, respectively. Furthermore, we used a two-alternative forced choice paradigm to measure the level of discrimination between trains of brief electrical stimuli, to gauge what the participant could reliably distinguish between. At best, the participant was able to distinguish a 0.5-Hz difference and on average acquired a 3.8-Hz just-noticeable difference at a more stringent psychophysical level. The current work shows the feasibility for long-term sensory feedback in prostheses, via electrical axonal stimulation, where small and relatively stable percepts were felt that may be used to deliver graded sensory feedback. This opens up opportunities for signaling feedback during movements (e.g., for precision grip), but also for conveying more complex cutaneous sensations, such as texture. NEW & NOTEWORTHY We demonstrate the long-term stability and generation of sensations from electrical peripheral nerve stimulation in an amputee, through an osseointegrated implant. We find that perceived tactilelike sensations could be generated for over 2 yr, in the missing hand. This is useful for prosthetic development and the implementation of feedback in artificial body parts.

Effect of Fiber Type, Water Content, and Velocity on Wetness Perception by the Volar Forearm Test: Stimulus Intensity Test

Perception ◽  
2019 ◽  
Vol 48 (9) ◽  
pp. 862-881 ◽  
Author(s):  
Zhaohua Zhang ◽  
Xiangning Tang ◽  
Yunyi Wang ◽  
Jun Li ◽  
Miao Tian ◽  
...  
Keyword(s):  
Water Content ◽  
Cooling Rate ◽  
Surface Texture ◽  
Moisture Transfer ◽  
Physical Parameters ◽  
Thermal Flow ◽  
Skin Cooling ◽  
Skin Wetness ◽  
Type Water ◽  
Transient Thermal

To investigate the effect of heat, moisture transfer, and mechanical tactile properties of fabrics on skin wetness perception when fabrics were in dynamic contact with skin at three velocities, nine knitted fabrics varying in fiber composition, thickness, and surface texture were evaluated by 20 participants using a wetness rating scale. The objective physical properties of the fabrics, namely, heat and moisture transfer and surface texture, and human physiological responses, namely, skin cooling rate and myoelectric signals, under various conditions were measured, and their correlations with the subjective wetness perception were studied. While the results indicated a significant influence of fabric type, water content, and velocity on skin wetness perception, no significant relation between electromyography and wetness perception was found. Fabrics with faster water spreading speeds and lower absorption rates were perceived as less wet, and the maximum transient thermal flow and skin cooling rate had a significant positive correlation with wetness perception. Furthermore, subjective wetness perception was predicted by the physical parameters of the fabric, that is, maximum transient thermal flow, water content, and friction coefficient, with an acceptable goodness of fit ( R2 = 0.82, p < .001).

scholarly journals The Contribution of Primary and Secondary Somatosensory Cortices to the Representation of Body Parts and Body Sides: An fMRI Adaptation Study

2012 ◽  
Vol 24 (12) ◽  
pp. 2306-2320 ◽  
Author(s):  
Luigi Tamè ◽  
Christoph Braun ◽  
Angelika Lingnau ◽  
Jens Schwarzbach ◽  
Gianpaolo Demarchi ◽  
...  
Keyword(s):  
Sensory Information ◽  
Middle Finger ◽  
The Body ◽  
Left Index Finger ◽  
Body Parts ◽  
Bold Response ◽  
Spatial Coding ◽  
Left Hand ◽  
Somatosensory Cortices ◽  
Fmri Adaptation

Although the somatosensory homunculus is a classically used description of the way somatosensory inputs are processed in the brain, the actual contributions of primary (SI) and secondary (SII) somatosensory cortices to the spatial coding of touch remain poorly understood. We studied adaptation of the fMRI BOLD response in the somatosensory cortex by delivering pairs of vibrotactile stimuli to the finger tips of the index and middle fingers. The first stimulus (adaptor) was delivered either to the index or to the middle finger of the right or left hand, and the second stimulus (test) was always administered to the left index finger. The overall BOLD response evoked by the stimulation was primarily contralateral in SI and was more bilateral in SII. However, our fMRI adaptation approach also revealed that both somatosensory cortices were sensitive to ipsilateral as well as to contralateral inputs. SI and SII adapted more after subsequent stimulation of homologous as compared with nonhomologous fingers, showing a distinction between different fingers. Most importantly, for both somatosensory cortices, this finger-specific adaptation occurred irrespective of whether the tactile stimulus was delivered to the same or to different hands. This result implies integration of contralateral and ipsilateral somatosensory inputs in SI as well as in SII. Our findings suggest that SI is more than a simple relay for sensory information and that both SI and SII contribute to the spatial coding of touch by discriminating between body parts (fingers) and by integrating the somatosensory input from the two sides of the body (hands).

scholarly journals Body mapping of cutaneous wetness perception across the human torso during thermo-neutral and warm environmental exposures

2014 ◽  
Vol 117 (8) ◽  
pp. 887-897 ◽  
Author(s):  
Davide Filingeri ◽  
Damien Fournet ◽  
Simon Hodder ◽  
George Havenith
Keyword(s):  
Regional Differences ◽  
Thermal Probe ◽  
Local Skin ◽  
Heterogeneous Distribution ◽  
Lower Back ◽  
Skin Cooling ◽  
Sensing Skin ◽  
Cold Sensitive ◽  
Skin Wetness ◽  
Thermal Pleasantness

Sensing skin wetness is linked to inputs arising from cutaneous cold-sensitive afferents. As thermosensitivity to cold varies significantly across the torso, we investigated whether similar regional differences in wetness perception exist. We also investigated the regional differences in thermal pleasantness and whether these sensory patterns are influenced by ambient temperature. Sixteen males (20 ± 2 yr) underwent a quantitative sensory test under thermo-neutral [air temperature (Tair) = 22°C; relative humidity (RH) = 50%] and warm conditions (Tair = 33°C; RH = 50%). Twelve regions of the torso were stimulated with a dry thermal probe (25 cm2) with a temperature of 15°C below local skin temperature (Tsk). Variations in Tsk, thermal, wetness, and pleasantness sensations were recorded. As a result of the same cold-dry stimulus, the skin-cooling response varied significantly by location ( P = 0.003). The lateral chest showed the greatest cooling (−5 ± 0.4°C), whereas the lower back showed the smallest (−1.9 ± 0.4°C). Thermal sensations varied significantly by location and independently from regional variations in skin cooling with colder sensations reported on the lateral abdomen and lower back. Similarly, the frequency of perceived skin wetness was significantly greater on the lateral and lower back as opposed to the medial chest. Overall wetness perception was slightly higher under warm conditions. Significantly more unpleasant sensations were recorded when the lateral abdomen and lateral and lower back were stimulated. We conclude that humans present regional differences in skin wetness perception across the torso, with a pattern similar to the regional differences in thermosensitivity to cold. These findings indicate the presence of a heterogeneous distribution of cold-sensitive thermo-afferent information.

scholarly journals Tactile cues significantly modulate the perception of sweat-induced skin wetness independently of the level of physical skin wetness

2015 ◽  
Vol 113 (10) ◽  
pp. 3462-3473 ◽  
Author(s):  
Davide Filingeri ◽  
Damien Fournet ◽  
Simon Hodder ◽  
George Havenith
Keyword(s):  
The Body ◽  
Whole Body ◽  
Exercise Protocol ◽  
Sweat Production ◽  
Skin Cooling ◽  
Tactile Cues ◽  
Skin Wetness ◽  
Low Threshold ◽  
Exercise Induced ◽  
Skin Mechanoreceptors

Humans sense the wetness of a wet surface through the somatosensory integration of thermal and tactile inputs generated by the interaction between skin and moisture. However, little is known on how wetness is sensed when moisture is produced via sweating. We tested the hypothesis that, in the absence of skin cooling, intermittent tactile cues, as coded by low-threshold skin mechanoreceptors, modulate the perception of sweat-induced skin wetness, independently of the level of physical wetness. Ten males (22 yr old) performed an incremental exercise protocol during two trials designed to induce the same physical skin wetness but to induce lower (TIGHT-FIT) and higher (LOOSE-FIT) wetness perception. In the TIGHT-FIT, a tight-fitting clothing ensemble limited intermittent skin-sweat-clothing tactile interactions. In the LOOSE-FIT, a loose-fitting ensemble allowed free skin-sweat-clothing interactions. Heart rate, core and skin temperature, galvanic skin conductance (GSC), and physical ( wbody) and perceived skin wetness were recorded. Exercise-induced sweat production and physical wetness increased significantly [GSC: 3.1 μS, SD 0.3 to 18.8 μS, SD 1.3, P < 0.01; wbody: 0.26 no-dimension units (nd), SD 0.02, to 0.92 nd, SD 0.01, P < 0.01], with no differences between TIGHT-FIT and LOOSE-FIT ( P > 0.05). However, the limited intermittent tactile inputs generated by the TIGHT-FIT ensemble reduced significantly whole-body and regional wetness perception ( P < 0.01). This reduction was more pronounced when between 40 and 80% of the body was covered in sweat. We conclude that the central integration of intermittent mechanical interactions between skin, sweat, and clothing, as coded by low-threshold skin mechanoreceptors, significantly contributes to the ability to sense sweat-induced skin wetness.

Body Parts Satisfaction Scale–Revised

2002 ◽  
Author(s):  
Trent A. Petrie ◽  
Margaret M. Tripp ◽  
Pejcharat Harvey
Keyword(s):  
Body Parts ◽  
Satisfaction Scale
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