Tactile roughness discrimination of the finger pad relies primarily on vibration sensitive afferents not necessarily located in the hand

2012 ◽  
Vol 229 (1) ◽  
pp. 273-279 ◽  
Author(s):  
Xavier Libouton ◽  
Olivier Barbier ◽  
Yorick Berger ◽  
Leon Plaghki ◽  
Jean-Louis Thonnard
Keyword(s):  
Tactile Roughness ◽  
Roughness Discrimination ◽  
Finger Pad

Effects of Sound on the Tactile Perception of Roughness in Peri-Head Space

2011 ◽  
Vol 24 (5) ◽  
pp. 471-483 ◽  
Author(s):  
Jiro Gyoba ◽  
Yuika Suzuki
Keyword(s):  
White Noise ◽  
Sound Source ◽  
Similar Pattern ◽  
Tactile Perception ◽  
Auditory Stimuli ◽  
Auditory Information ◽  
Head Space ◽  
Tactile Stimuli ◽  
Tactile Roughness ◽  
Roughness Discrimination

AbstractThe aim of this study is to investigate whether or not spatial congruency between tactile and auditory stimuli would influence the tactile roughness discrimination of stimuli presented to the fingers or cheeks. In the experiment, when abrasive films were passively presented to the participants, white noise bursts were simultaneously presented from the same or different side, either near or far from the head. The results showed that when white noise was presented from the same side as the tactile stimuli, especially from near the head, the discrimination sensitivity on the cheeks was higher than when sound was absent or presented from a different side. A similar pattern was observed in discrimination by the fingers but it was not significant. The roughness discrimination by the fingers was also influenced by the presentation of sound close to the head, but significant differences between conditions with and without sounds were observed at the decisional level. Thus, the spatial congruency between tactile and auditory information selectively modulated the roughness sensitivity of the skin on the cheek, especially when the sound source was close to the head.

Tactile roughness discrimination threshold is unrelated to tactile spatial acuity

2010 ◽  
Vol 208 (2) ◽  
pp. 473-478 ◽  
Author(s):  
Xavier Libouton ◽  
Olivier Barbier ◽  
Leon Plaghki ◽  
Jean-Louis Thonnard
Keyword(s):  
Discrimination Threshold ◽  
Spatial Acuity ◽  
Tactile Roughness ◽  
Roughness Discrimination

scholarly journals The neural code for tactile roughness in the somatosensory nerves

2017 ◽  
Vol 118 (6) ◽  
pp. 3107-3117 ◽  
Author(s):  
Justin D. Lieber ◽  
Xinyue Xia ◽  
Alison I. Weber ◽  
Sliman J. Bensmaia
Keyword(s):  
Fiber Type ◽  
Rhesus Macaques ◽  
Discrimination Performance ◽  
Nerve Fibers ◽  
Neural Code ◽  
Population Response ◽  
Perceptual Dimension ◽  
Tactile Roughness ◽  
Roughness Discrimination ◽  
Sense Of Touch

Roughness is the most salient perceptual dimension of surface texture but has no well-defined physical basis. We seek to determine the neural determinants of tactile roughness in the somatosensory nerves. Specifically, we record the patterns of activation evoked in tactile nerve fibers of anesthetized Rhesus macaques to a large and diverse set of natural textures and assess what aspect of these patterns of activation can account for psychophysical judgments of roughness, obtained from human observers. We show that perceived roughness is determined by the variation in the population response, weighted by fiber type. That is, a surface will feel rough to the extent that the activity varies across nerve fibers and varies across time within nerve fibers. We show that this variation-based neural code can account not only for magnitude estimates of roughness but also for roughness discrimination performance. NEW & NOTEWORTHY Our sense of touch endows us with an exquisite sensitivity to the microstructure of surfaces, the most salient aspect of which is roughness. We analyze the responses evoked in tactile fibers of monkeys by natural textures and compare them to judgments of roughness obtained for the same textures from human observers. We then describe how texture signals from three populations of nerve fibers are integrated to culminate in a percept of roughness.

Physical determinants of the shape of the psychophysical curve relating tactile roughness to raised-dot spacing: implications for neuronal coding of roughness

2013 ◽  
Vol 109 (5) ◽  
pp. 1403-1415 ◽  
Author(s):  
Adrian Sutu ◽  
El-Mehdi Meftah ◽  
C. Elaine Chapman
Keyword(s):  
Psychometric Function ◽  
Weber Fraction ◽  
Critical Issue ◽  
Linear Increase ◽  
Spatial Period ◽  
Invariant Relation ◽  
Monotonic Increase ◽  
Neuronal Coding ◽  
Tactile Roughness ◽  
Roughness Discrimination

There are conflicting reports as to whether the shape of the psychometric relation between perceived roughness and tactile element spacing [spatial period (SP)] follows an inverted U-shape or a monotonic linear increase. This is a critical issue because the former result has been used to assess neuronal codes for roughness. We tested the hypothesis that the relation's shape is critically dependent on tactile element height (raised dots). Subjects rated the roughness of low (0.36 mm)- and high (1.8 mm)-raised-dot surfaces displaced under their fingertip. Inverted U-shaped curves were obtained as the SP of low-dot surfaces was increased (1.3–6.2 mm, tetragonal arrays); a monotonic increase was observed for high-dot surfaces. We hypothesized that roughness is not a single sensory continuum across the tested SPs of low-dot surfaces, predicting that roughness discrimination would show deviations from the invariant relation between threshold (ΔS) and the value of the standard (S) surface (Weber fraction, ΔS/S) expected for a single continuum. The results showed that Weber fractions were increased for SPs on the descending limb of the inverted U-shaped curve. There was also an increase in the Weber fraction for high-dot surfaces but only at the peak (3 mm), corresponding to the SP at which the slope of the psychometric function showed a modest decline. Together the results indicate that tactile roughness is not a continuum across low-dot SPs of 1.3–6.2 mm. These findings suggest that correlating the inverted U-shaped function with neuronal codes is of questionable validity. A simple intensive code may well contribute to tactile roughness.

scholarly journals Neuronalis összeköttetések a szomatoszenzoros kérgi área 3b és área 1 kézreprezentációs területén főemlősökben

2016 ◽  
Vol 157 (33) ◽  
pp. 1320-1325
Author(s):  
Emese Pálfi ◽  
Mária Ashaber ◽  
Cory Palmer ◽  
Robert M. Friedman ◽  
Anna W. Roe ◽  
...  
Keyword(s):  
Functional Relationship ◽  
Hand Movement ◽  
Saimiri Sciureus ◽  
Skin Area ◽  
Tract Tracing ◽  
Reciprocal Connections ◽  
Representation Method ◽  
Local Input ◽  
Finger Pad ◽  
Area 3B

Introduction: The close functional relationship between areas 3b and 1 of the somatosensory cortex is based on their reciprocal connections indicating that tactile sensation depends on the interaction of these two areas. Aim: The aim of the authors was to explore this neuronal circuit at the level of the distal finger pad representation. Method: The study was made by bidirectional tract tracing aided by neurophysiological mapping in squirrel monkeys (Saimiri sciureus). Results: Inter-areal connections between the two areas preferred the homologues representations. However, intra-areal connections were formed between the neighboring finger pad representations supporting the physiological observations. Interestingly, the size of the local input area of the injected cortical micro-region, which differed in the two areas, represented the same skin area. Conclusions: The authors propose that intra-areal connections are important in integrating information across fingers, while inter-areal connections are important in maintaining input localization during hand movement. Orv. Hetil., 2016, 157(33), 1320–1325.

scholarly journals Investigating the Trackability of Silicon Microprobes in High-Speed Surface Measurements

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1557
Author(s):  
Min Xu ◽  
Zhi Li ◽  
Michael Fahrbach ◽  
Erwin Peiner ◽  
Uwe Brand
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
High Signal ◽  
Resonant Response ◽  
High Demand ◽  
Surface Measurements ◽  
Tactile Roughness ◽  
Low Mass ◽  
Roughness Measurements

High-speed tactile roughness measurements set high demand on the trackability of the stylus probe. Because of the features of low mass, low probing force, and high signal linearity, the piezoresistive silicon microprobe is a hopeful candidate for high-speed roughness measurements. This paper investigates the trackability of these microprobes through building a theoretical dynamic model, measuring their resonant response, and performing tip-flight experiments on surfaces with sharp variations. Two microprobes are investigated and compared: one with an integrated silicon tip and one with a diamond tip glued to the end of the cantilever. The result indicates that the microprobe with the silicon tip has high trackability for measurements up to traverse speeds of 10 mm/s, while the resonant response of the microprobe with diamond tip needs to be improved for the application in high-speed topography measurements.

scholarly journals The limited contribution of early visual cortex in visual working memory for surface roughness

2020 ◽  
Author(s):  
Munendo Fujimichi ◽  
Hiroki Yamamoto ◽  
Jun Saiki
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Brain Activity ◽  
Visual Representations ◽  
Brain Regions ◽  
Daily Lives ◽  
Early Visual Cortex ◽  
Roughness Discrimination ◽  
Visual Properties

Are visual representations in the human early visual cortex necessary for visual working memory (VWM)? Previous studies suggest that VWM is underpinned by distributed representations across several brain regions, including the early visual cortex. Notably, in these studies, participants had to memorize images under consistent visual conditions. However, in our daily lives, we must retain the essential visual properties of objects despite changes in illumination or viewpoint. The role of brain regions—particularly the early visual cortices—in these situations remains unclear. The present study investigated whether the early visual cortex was essential for achieving stable VWM. Focusing on VWM for object surface properties, we conducted fMRI experiments while male and female participants performed a delayed roughness discrimination task in which sample and probe spheres were presented under varying illumination. By applying multi-voxel pattern analysis to brain activity in regions of interest, we found that the ventral visual cortex and intraparietal sulcus were involved in roughness VWM under changing illumination conditions. In contrast, VWM was not supported as robustly by the early visual cortex. These findings show that visual representations in the early visual cortex alone are insufficient for the robust roughness VWM representation required during changes in illumination.

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