Brain regions that retain the spatial layout of tactile stimuli during working memory - A 'tactospatial sketchpad'?

PubMed

Schmidt, Timo Torsten; Blankenburg, Felix

2018-05-31

Working memory (WM) studies have been essential for ascertaining how the brain flexibly handles mentally represented information in the absence of sensory stimulation. Most studies on the memory of sensory stimulus features have focused, however, on the visual domain. Here, we report a human WM study in the tactile modality where participants had to memorize the spatial layout of patterned Braille-like stimuli presented to the index finger. We used a whole-brain searchlight approach in combination with multi-voxel pattern analysis (MVPA) to investigate tactile WM representations without a priori assumptions about which brain regions code tactospatial information. Our analysis revealed that posterior and parietal cortices, as well as premotor regions, retained information across the twelve-second delay phase. Interestingly, parts of this brain network were previously shown to also contain information of visuospatial WM. Also, by specifically testing somatosensory regions for WM representations, we observed content-specific activation patterns in primary somatosensory cortex (SI). Our findings demonstrate that tactile WM depends on a distributed network of brain regions in analogy to the representation of visuospatial information. Copyright © 2018. Published by Elsevier Inc.

An Adaptation-Induced Repulsion Illusion in Tactile Spatial Perception

PubMed Central

Li, Lux; Chan, Arielle; Iqbal, Shah M.; Goldreich, Daniel

2017-01-01

Following focal sensory adaptation, the perceived separation between visual stimuli that straddle the adapted region is often exaggerated. For instance, in the tilt aftereffect illusion, adaptation to tilted lines causes subsequently viewed lines with nearby orientations to be perceptually repelled from the adapted orientation. Repulsion illusions in the nonvisual senses have been less studied. Here, we investigated whether adaptation induces a repulsion illusion in tactile spatial perception. In a two-interval forced-choice task, participants compared the perceived separation between two point-stimuli applied on the forearms successively. Separation distance was constant on one arm (the reference) and varied on the other arm (the comparison). In Experiment 1, we took three consecutive baseline measurements, verifying that in the absence of manipulation, participants’ distance perception was unbiased across arms and stable across experimental blocks. In Experiment 2, we vibrated a region of skin on the reference arm, verifying that this focally reduced tactile sensitivity, as indicated by elevated monofilament detection thresholds. In Experiment 3, we applied vibration between the two reference points in our distance perception protocol and discovered that this caused an illusory increase in the separation between the points. We conclude that focal adaptation induces a repulsion aftereffect illusion in tactile spatial perception. The illusion provides clues as to how the tactile system represents spatial information. The analogous repulsion aftereffects caused by adaptation in different stimulus domains and sensory systems may point to fundamentally similar strategies for dynamic sensory coding. PMID:28701936

Tactile Stimulation of the Face and the Production of Facial Expressions Activate Neurons in the Primate Amygdala

PubMed Central

Mosher, Clayton P.; Zimmerman, Prisca E.; Fuglevand, Andrew J.

2016-01-01

Abstract The majority of neurophysiological studies that have explored the role of the primate amygdala in the evaluation of social signals have relied on visual stimuli such as images of facial expressions. Vision, however, is not the only sensory modality that carries social signals. Both humans and nonhuman primates exchange emotionally meaningful social signals through touch. Indeed, social grooming in nonhuman primates and caressing touch in humans is critical for building lasting and reassuring social bonds. To determine the role of the amygdala in processing touch, we recorded the responses of single neurons in the macaque amygdala while we applied tactile stimuli to the face. We found that one-third of the recorded neurons responded to tactile stimulation. Although we recorded exclusively from the right amygdala, the receptive fields of 98% of the neurons were bilateral. A fraction of these tactile neurons were monitored during the production of facial expressions and during facial movements elicited occasionally by touch stimuli. Firing rates arising during the production of facial expressions were similar to those elicited by tactile stimulation. In a subset of cells, combining tactile stimulation with facial movement further augmented the firing rates. This suggests that tactile neurons in the amygdala receive input from skin mechanoceptors that are activated by touch and by compressions and stretches of the facial skin during the contraction of the underlying muscles. Tactile neurons in the amygdala may play a role in extracting the valence of touch stimuli and/or monitoring the facial expressions of self during social interactions. PMID:27752543

Tactile Stimulation of the Face and the Production of Facial Expressions Activate Neurons in the Primate Amygdala.

PubMed

Mosher, Clayton P; Zimmerman, Prisca E; Fuglevand, Andrew J; Gothard, Katalin M

2016-01-01

The majority of neurophysiological studies that have explored the role of the primate amygdala in the evaluation of social signals have relied on visual stimuli such as images of facial expressions. Vision, however, is not the only sensory modality that carries social signals. Both humans and nonhuman primates exchange emotionally meaningful social signals through touch. Indeed, social grooming in nonhuman primates and caressing touch in humans is critical for building lasting and reassuring social bonds. To determine the role of the amygdala in processing touch, we recorded the responses of single neurons in the macaque amygdala while we applied tactile stimuli to the face. We found that one-third of the recorded neurons responded to tactile stimulation. Although we recorded exclusively from the right amygdala, the receptive fields of 98% of the neurons were bilateral. A fraction of these tactile neurons were monitored during the production of facial expressions and during facial movements elicited occasionally by touch stimuli. Firing rates arising during the production of facial expressions were similar to those elicited by tactile stimulation. In a subset of cells, combining tactile stimulation with facial movement further augmented the firing rates. This suggests that tactile neurons in the amygdala receive input from skin mechanoceptors that are activated by touch and by compressions and stretches of the facial skin during the contraction of the underlying muscles. Tactile neurons in the amygdala may play a role in extracting the valence of touch stimuli and/or monitoring the facial expressions of self during social interactions.

Visual detail about the body modulates tactile localisation biases.

PubMed

Margolis, Aaron N; Longo, Matthew R

2015-02-01

The localisation of tactile stimuli requires the integration of visual and somatosensory inputs within an internal representation of the body surface and is prone to consistent bias. Joints may play a role in segmenting such internal body representations, and may therefore influence tactile localisation biases, although the nature of this influence remains unclear. Here, we investigate the relationship between conceptual knowledge of joint locations and tactile localisation biases on the hand. In one task, participants localised tactile stimuli applied to the dorsum of their hand. A distal localisation bias was observed in all participants, consistent with previous results. We also manipulated the availability of visual information during this task, to determine whether the absence of this information could account for the distal bias observed here and by Mancini et al. (Neuropsychologia 49:1194-1201, 2011). The observed distal bias increased in magnitude when visual information was restricted, without a corresponding decrease in precision. In a separate task, the same participants indicated, from memory, knuckle locations on a silhouette image of their hand. Analogous distal biases were also seen in the knuckle localisation task. The accuracy of conceptual joint knowledge was not correlated with tactile localisation bias magnitude, although a similarity in observed bias direction suggests that both tasks may rely on a common, higher-order body representation. These results also suggest that distortions of conceptual body representation may be more common in healthy individuals than previously thought.

The Cognitive and Neural Correlates of Tactile Memory

ERIC Educational Resources Information Center

Gallace, Alberto; Spence, Charles

2009-01-01

Tactile memory systems are involved in the storage and retrieval of information about stimuli that impinge on the body surface and objects that people explore haptically. Here, the authors review the behavioral, neuropsychological, neurophysiological, and neuroimaging research on tactile memory. This body of research reveals that tactile memory…

When Content Matters: The Role of Processing Code in Tactile Display Design.

PubMed

Ferris, Thomas K; Sarter, Nadine

2010-01-01

The distribution of tasks and stimuli across multiple modalities has been proposed as a means to support multitasking in data-rich environments. Recently, the tactile channel and, more specifically, communication via the use of tactile/haptic icons have received considerable interest. Past research has examined primarily the impact of concurrent task modality on the effectiveness of tactile information presentation. However, it is not well known to what extent the interpretation of iconic tactile patterns is affected by another attribute of information: the information processing codes of concurrent tasks. In two driving simulation studies (n = 25 for each), participants decoded icons composed of either spatial or nonspatial patterns of vibrations (engaging spatial and nonspatial processing code resources, respectively) while concurrently interpreting spatial or nonspatial visual task stimuli. As predicted by Multiple Resource Theory, performance was significantly worse (approximately 5-10 percent worse) when the tactile icons and visual tasks engaged the same processing code, with the overall worst performance in the spatial-spatial task pairing. The findings from these studies contribute to an improved understanding of information processing and can serve as input to multidimensional quantitative models of timesharing performance. From an applied perspective, the results suggest that competition for processing code resources warrants consideration, alongside other factors such as the naturalness of signal-message mapping, when designing iconic tactile displays. Nonspatially encoded tactile icons may be preferable in environments which already rely heavily on spatial processing, such as car cockpits.

Tactile priming modulates the activation of the fronto-parietal circuit during tactile angle match and non-match processing: an fMRI study

PubMed Central

Yang, Jiajia; Yu, Yinghua; Kunita, Akinori; Huang, Qiang; Wu, Jinglong; Sawamoto, Nobukatsu; Fukuyama, Hidenao

2014-01-01

The repetition of a stimulus task reduces the neural activity within certain cortical regions responsible for working memory (WM) processing. Although previous evidence has shown that repeated vibrotactile stimuli reduce the activation in the ventrolateral prefrontal cortex, whether the repeated tactile spatial stimuli triggered the priming effect correlated with the same cortical region remains unclear. Therefore, we used event-related functional magnetic resonance imaging (fMRI) and a delayed match-to-sample task to investigate the contributions of the priming effect to tactile spatial WM processing. Fourteen healthy volunteers were asked to encode three tactile angle stimuli during the encoding phase and one tactile angle stimulus during the recognition phase. Then, they answered whether the last angle stimulus was presented during the encoding phase. As expected, both the Match and Non-Match tasks activated a similar cerebral network. The critical new finding was decreased brain activity in the left inferior frontal gyrus (IFG), the right posterior parietal cortex (PPC) and bilateral medial frontal gyri (mFG) for the match task compared to the Non-Match task. Therefore, we suggest that the tactile priming engaged repetition suppression mechanisms during tactile angle matching, and this process decreased the activation of the fronto-parietal circuit, including IFG, mFG and PPC. PMID:25566010

Tactile roughness perception in the presence of olfactory and trigeminal stimulants

PubMed Central

Koijck, Lara A.; Van Erp, Jan B.F.

2015-01-01

Previous research has shown that odorants consistently evoke associations with textures and their tactile properties like smoothness and roughness. Also, it has been observed that olfaction can modulate tactile perception. We therefore hypothesized that tactile roughness perception may be biased towards the somatosensory connotation of an ambient odorant. We performed two experiments to test this hypothesis. In the first experiment, we investigated the influence of ambient chemosensory stimuli with different roughness connotations on tactile roughness perception. In addition to a pleasant odor with a connotation of softness (PEA), we also included a trigeminal stimulant with a rough, sharp or prickly connotation (Ethanol). We expected that—compared to a No-odorant control condition—tactile texture perception would be biased towards smoothness in the presence of PEA and towards roughness in the presence of Ethanol. However, our results show no significant interaction between chemosensory stimulation and perceived tactile surface roughness. It could be argued that ambient odors may be less effective in stimulating crossmodal associations, since they are by definition extraneous to the tactile stimuli. In an attempt to optimize the conditions for sensory integration, we therefore performed a second experiment in which the olfactory and tactile stimuli were presented in synchrony and in close spatial proximity. In addition, we included pleasant (Lemon) and unpleasant (Indole) odorants that are known to have the ability to affect tactile perception. We expected that tactile stimuli would be perceived as less rough when simultaneously presented with Lemon or PEA (both associated with softness) than when presented with Ethanol or Indole (odors that can be associated with roughness). Again, we found no significant main effect of chemosensory condition on perceived tactile roughness. We discuss the limitations of this study and we present suggestions for future research

The role of automatic orienting of attention towards ipsilesional stimuli in non-visual (tactile and auditory) neglect: a critical review.

PubMed

Gainotti, Guido

2010-02-01

The aim of the present survey was to review scientific articles dealing with the non-visual (auditory and tactile) forms of neglect to determine: (a) whether behavioural patterns similar to those observed in the visual modality can also be observed in the non-visual modalities; (b) whether a different severity of neglect can be found in the visual and in the auditory and tactile modalities; (c) the reasons for the possible differences between the visual and non-visual modalities. Data pointing to a contralesional orienting of attention in the auditory and the tactile modalities in visual neglect patients were separately reviewed. Results showed: (a) that in patients with right brain damage manifestations of neglect for the contralesional side of space can be found not only in the visual but also in the auditory and tactile modalities; (b) that the severity of neglect is greater in the visual than in the non-visual modalities. This asymmetry in the severity of neglect across modalities seems due to the greater role that the automatic capture of attention by irrelevant ipsilesional stimuli seems to play in the visual modality. Copyright 2009 Elsevier Srl. All rights reserved.

Piezoelectric Polymer Tactile Sensor Arrays for Robotics.

DTIC Science & Technology

1987-12-01

response to slow and fast stimuli (Dario and others, 1984:2). The touch receptors relate tactile information through a variety of tactile sensory...flexure. The only occurrence when an evaporated electrode broke (and became intermit - tently open circuited) was during the measurement of the PPTSA *4

Audio-Visual, Visuo-Tactile and Audio-Tactile Correspondences in Preschoolers.

PubMed

Nava, Elena; Grassi, Massimo; Turati, Chiara

2016-01-01

Interest in crossmodal correspondences has recently seen a renaissance thanks to numerous studies in human adults. Yet, still very little is known about crossmodal correspondences in children, particularly in sensory pairings other than audition and vision. In the current study, we investigated whether 4-5-year-old children match auditory pitch to the spatial motion of visual objects (audio-visual condition). In addition, we investigated whether this correspondence extends to touch, i.e., whether children also match auditory pitch to the spatial motion of touch (audio-tactile condition) and the spatial motion of visual objects to touch (visuo-tactile condition). In two experiments, two different groups of children were asked to indicate which of two stimuli fitted best with a centrally located third stimulus (Experiment 1), or to report whether two presented stimuli fitted together well (Experiment 2). We found sensitivity to the congruency of all of the sensory pairings only in Experiment 2, suggesting that only under specific circumstances can these correspondences be observed. Our results suggest that pitch-height correspondences for audio-visual and audio-tactile combinations may still be weak in preschool children, and speculate that this could be due to immature linguistic and auditory cues that are still developing at age five.

The phase of prestimulus alpha oscillations affects tactile perception.

PubMed

Ai, Lei; Ro, Tony

2014-03-01

Previous studies have shown that neural oscillations in the 8- to 12-Hz range influence sensory perception. In the current study, we examined whether both the power and phase of these mu/alpha oscillations predict successful conscious tactile perception. Near-threshold tactile stimuli were applied to the left hand while electroencephalographic (EEG) activity was recorded over the contralateral right somatosensory cortex. We found a significant inverted U-shaped relationship between prestimulus mu/alpha power and detection rate, suggesting that there is an intermediate level of alpha power that is optimal for tactile perception. We also found a significant difference in phase angle concentration at stimulus onset that predicted whether the upcoming tactile stimulus was perceived or missed. As has been shown in the visual system, these findings suggest that these mu/alpha oscillations measured over somatosensory areas exert a strong inhibitory control on tactile perception and that pulsed inhibition by these oscillations shapes the state of brain activity necessary for conscious perception. They further suggest that these common phasic processing mechanisms across different sensory modalities and brain regions may reflect a common underlying encoding principle in perceptual processing that leads to momentary windows of perceptual awareness.

Unmyelinated tactile cutaneous nerves signal erotic sensations.

PubMed

Jönsson, Emma H; Backlund Wasling, Helena; Wagnbeck, Vicktoria; Dimitriadis, Menelaos; Georgiadis, Janniko R; Olausson, Håkan; Croy, Ilona

2015-06-01

Intrapersonal touch is a powerful tool for communicating emotions and can among many things evoke feelings of eroticism and sexual arousal. The peripheral neural mechanisms of erotic touch signaling have been less studied. C tactile afferents (unmyelinated low-threshold mechanoreceptors), known to underpin pleasant aspects of touch processing, have been posited to play an important role. In two studies, we investigated the relationship between C tactile activation and the perception of erotic and pleasant touch, using tactile brushing stimulation. In total, 66 healthy subjects (37 women, age range 19-51 years) were examined. In study 1 (n = 20), five different stroking velocities were applied to the forearm and the inner thigh. The participants answered questions about partnership, mood, and touch. In study 2 (n = 46), the same five stroking velocities were applied to the forearm. The participants answered questions about partnership, touch, and sexuality. Both touch eroticism and pleasantness were rated significantly higher for C tactile optimal velocities compared with suboptimal velocities. No difference was found between the ratings of the thigh and the forearm. The velocity-dependent rating curves of pleasantness, intensity, and eroticism differed from each other. Pleasantness was best explained by a quadratic fit, intensity by a linear fit, and eroticism by both. A linear transformation of pleasantness and intensity predicted the observed eroticism ratings reliably. Eroticism ratings were negatively correlated with length of relationship. Touch was rated most erotic when perceived as pleasant and weak. In human hairy skin, perception of pleasantness is correlated with the firing rate of C tactile afferents, and perception of intensity is correlated with the firing rate of Aβ afferents. Accordingly, eroticism may be perceived most readily for touch stimuli that induce high activity in C tactile fibers and low activity in Aβ fibers. © 2015 International

Auditory-tactile echo-reverberating stuttering speech corrector

NASA Astrophysics Data System (ADS)

Kuniszyk-Jozkowiak, Wieslawa; Adamczyk, Bogdan

1997-02-01

The work presents the construction of a device, which transforms speech sounds into acoustical and tactile signals of echo and reverberation. Research has been done on the influence of the echo and reverberation, which are transmitted as acoustic and tactile stimuli, on speech fluency. Introducing the echo or reverberation into the auditory feedback circuit results in a reduction of stuttering. A bit less, but still significant corrective effects are observed while using the tactile channel for transmitting the signals. The use of joined auditory and tactile channels increases the effects of their corrective influence on the stutterers' speech. The results of the experiment justify the use of the tactile channel in the stutterers' therapy.

Those are Your Legs: The Effect of Visuo-Spatial Viewpoint on Visuo-Tactile Integration and Body Ownership

PubMed Central

Pozeg, Polona; Galli, Giulia; Blanke, Olaf

2015-01-01

Experiencing a body part as one’s own, i.e., body ownership, depends on the integration of multisensory bodily signals (including visual, tactile, and proprioceptive information) with the visual top-down signals from peripersonal space. Although it has been shown that the visuo-spatial viewpoint from where the body is seen is an important visual top-down factor for body ownership, different studies have reported diverging results. Furthermore, the role of visuo-spatial viewpoint (sometime also called first-person perspective) has only been studied for hands or the whole body, but not for the lower limbs. We thus investigated whether and how leg visuo-tactile integration and leg ownership depended on the visuo-spatial viewpoint from which the legs were seen and the anatomical similarity of the visual leg stimuli. Using a virtual leg illusion, we tested the strength of visuo-tactile integration of leg stimuli using the crossmodal congruency effect (CCE) as well as the subjective sense of leg ownership (assessed by a questionnaire). Fifteen participants viewed virtual legs or non-corporeal control objects, presented either from their habitual first-person viewpoint or from a viewpoint that was rotated by 90°(third-person viewpoint), while applying visuo-tactile stroking between the participants legs and the virtual legs shown on a head-mounted display. The data show that the first-person visuo-spatial viewpoint significantly boosts the visuo-tactile integration as well as the sense of leg ownership. Moreover, the viewpoint-dependent increment of the visuo-tactile integration was only found in the conditions when participants viewed the virtual legs (absent for control objects). These results confirm the importance of first person visuo-spatial viewpoint for the integration of visuo-tactile stimuli and extend findings from the upper extremity and the trunk to visuo-tactile integration and ownership for the legs. PMID:26635663

Where are my hands? Influence of limb posture on tactile extinction.

PubMed

Auclair, Laurent; Barra, Julien; Raibaut, Patrick

2012-05-01

Tactile localization on the skin involves both a somatotopic and a postural schema (body-schema) representation. The present study determines the extent to which body posture influences tactile perception in right-brain-damaged patients. In a first set of experiments, patients were asked to detect single tactile stimulation delivered to their left or right hands or to both hands simultaneously (double stimulation) in different arm postures. Only patients who had no difficulty localizing single and double tactile stimulations when their hands were placed in anatomic position were tested. Participant's hands were crossed, one over the other, and the tactile stimuli were delivered either to the hand (beyond the crossing point, Experiment 1) or to the forearm (before the crossing point, Experiment 2). In Experiment 3, the left hand was placed in the right hemispace and the right hand in the left hemispace without crossing over (opposite condition). In a second set of experiments, patients were asked to detect stimulation delivered to the forefinger. The fingers were crossed, one over the other at the level of the middle phalanx, and stimuli were delivered either beyond or before the crossing point. In all experimental conditions, control participants performed at ceiling. We observed a left-hand tactile extinction on double stimulation in the crossed condition. These results suggest that tactile stimuli can be encoded based on multiple specific body-part representations rather than on an integrated body-schema representation.

Tactile functions after cerebral hemispherectomy.

PubMed

Backlund, H; Morin, C; Ptito, A; Bushnell, M C; Olausson, H

2005-01-01

Patients that were hemispherectomized due to brain lesions early in life sometimes have remarkably well-preserved tactile functions on their paretic body half. This has been attributed to developmental neuroplasticity. However, the tactile examinations generally have been fairly crude, and subtle deficits may not have been revealed. We investigated monofilament detection and three types of tactile directional sensibility in four hemispherectomized patients and six healthy controls. Patients were examined bilaterally on the face, forearm and lower leg. Normal subjects were examined unilaterally. Following each test of directional sensibility, subjects were asked to rate the intensity of the stimulation. On the nonparetic side, results were almost always in the normal range. On the paretic side, the patients' capacity for monofilament detection was less impaired than their directional sensibility. Despite the disturbed directional sensibility on their paretic side the patients rated tactile sensations evoked by the stimuli, on both their paretic and nonparetic body halves, as more intense than normals. Thus, mechanisms of plasticity seem adequate for tactile detection and intensity coding but not for more complex tactile functions such as directional sensibility. The reason for the high vulnerability of tactile directional sensibility may be that it depends on spatially and temporally precise afferent information processed in a distributed cortical network.

Decoding tactile afferent activity to obtain an estimate of instantaneous force and torque applied to the fingerpad

PubMed Central

Birznieks, Ingvars; Redmond, Stephen J.

2015-01-01

Dexterous manipulation is not possible without sensory information about object properties and manipulative forces. Fundamental neuroscience has been unable to demonstrate how information about multiple stimulus parameters may be continuously extracted, concurrently, from a population of tactile afferents. This is the first study to demonstrate this, using spike trains recorded from tactile afferents innervating the monkey fingerpad. A multiple-regression model, requiring no a priori knowledge of stimulus-onset times or stimulus combination, was developed to obtain continuous estimates of instantaneous force and torque. The stimuli consisted of a normal-force ramp (to a plateau of 1.8, 2.2, or 2.5 N), on top of which −3.5, −2.0, 0, +2.0, or +3.5 mNm torque was applied about the normal to the skin surface. The model inputs were sliding windows of binned spike counts recorded from each afferent. Models were trained and tested by 15-fold cross-validation to estimate instantaneous normal force and torque over the entire stimulation period. With the use of the spike trains from 58 slow-adapting type I and 25 fast-adapting type I afferents, the instantaneous normal force and torque could be estimated with small error. This study demonstrated that instantaneous force and torque parameters could be reliably extracted from a small number of tactile afferent responses in a real-time fashion with stimulus combinations that the model had not been exposed to during training. Analysis of the model weights may reveal how interactions between stimulus parameters could be disentangled for complex population responses and could be used to test neurophysiologically relevant hypotheses about encoding mechanisms. PMID:25948866

Displaying Sensed Tactile Cues with a Fingertip Haptic Device.

PubMed

Pacchierotti, Claudio; Prattichizzo, Domenico; Kuchenbecker, Katherine J

2015-01-01

Telerobotic systems enable humans to explore and manipulate remote environments for applications such as surgery and disaster response, but few such systems provide the operator with cutaneous feedback. This article presents a novel approach to remote cutaneous interaction; our method is compatible with any fingertip tactile sensor and any mechanical tactile display device, and it does not require a position/force or skin deformation model. Instead, it directly maps the sensed stimuli to the best possible input commands for the device's motors using a data set recorded with the tactile sensor inside the device. As a proof of concept, we considered a haptic system composed of a BioTac tactile sensor, in charge of measuring contact deformations, and a custom 3-DoF cutaneous device with a flat contact platform, in charge of applying deformations to the user's fingertip. To validate the proposed approach and discover its inherent tradeoffs, we carried out two remote tactile interaction experiments. The first one evaluated the error between the tactile sensations registered by the BioTac in a remote environment and the sensations created by the cutaneous device for six representative tactile interactions and 27 variations of the display algorithm. The normalized average errors in the best condition were 3.0 percent of the BioTac's full 12-bit scale. The second experiment evaluated human subjects' experiences for the same six remote interactions and eight algorithm variations. The average subjective rating for the best algorithm variation was 8.2 out of 10, where 10 is best.

Tactile responses of hindpaw, forepaw and whisker neurons in the thalamic ventrobasal complex of anesthetized rats

PubMed Central

Aguilar, J; Morales-Botello, M L; Foffani, G

2008-01-01

The majority of studies investigating responses of thalamocortical neurons to tactile stimuli have focused on the whisker representation of the rat thalamus: the ventral–posterior–medial nucleus (VPM). To test whether the basic properties of thalamocortical responses to tactile stimuli could be extended to the entire ventrobasal complex, we recorded single neurons from the whisker, forepaw and hindpaw thalamic representations. We performed a systematic analysis of responses to stereotyped tactile stimuli − 500 ms pulses (i.e. ON–OFF stimuli) or 1 ms pulses (i.e. impulsive stimuli) − under two different anesthetics (pentobarbital or urethane). We obtained the following main results: (i) the tuning of cells to ON vs. OFF stimuli displayed a gradient across neurons, so that two-thirds of cells responded more to ON stimuli and one-third responded more to OFF stimuli; (ii) on average, response magnitudes did not differ between ON and OFF stimuli, whereas latencies of response to OFF stimuli were a few milliseconds longer; (iii) latencies of response to ON and OFF stimuli were highly correlated; (iv) responses to impulsive stimuli and ON stimuli showed a strong correlation, whereas the relationship between the responses to impulsive stimuli and OFF stimuli was subtler; (v) unlike ON responses, OFF responses did not decrease when stimuli were moved from the receptive field center to a close location in the excitatory surround. We obtained the same results for hindpaw, forepaw and whisker neurons. Our results support the view of a neurophysiologically homogeneous ventrobasal complex, in which OFF responses participate in the structure of the spatiotemporal receptive field of thalamocortical neurons for tactile stimuli. PMID:18190520

Generalization of a tactile stimulus in horses.

PubMed Central

Dougherty, D M; Lewis, P

1993-01-01

Using horses, we investigated the control of operant behavior by a tactile stimulus (the training stimulus) and the generalization of behavior to six other similar test stimuli. In a stall, the experimenters mounted a response panel in the doorway. Located on this panel were a response lever and a grain dispenser. The experimenters secured a tactile-stimulus belt to the horse's back. The stimulus belt was constructed by mounting seven solenoids along a piece of burlap in a manner that allowed each to provide the delivery of a tactile stimulus, a repetitive light tapping, at different locations (spaced 10.0 cm apart) along the horse's back. Two preliminary steps were necessary before generalization testing: training a measurable response (lip pressing) and training on several reinforcement schedules in the presence of a training stimulus (tapping by one of the solenoids). We then gave each horse two generalization test sessions. Results indicated that the horses' behavior was effectively controlled by the training stimulus. Horses made the greatest number of responses to the training stimulus, and the tendency to respond to the other test stimuli diminished as the stimuli became farther away from the training stimulus. These findings are discussed in the context of behavioral principles and their relevance to the training of horses. PMID:8315368

Generalization of a tactile stimulus in horses.

PubMed

Dougherty, D M; Lewis, P

1993-05-01

Using horses, we investigated the control of operant behavior by a tactile stimulus (the training stimulus) and the generalization of behavior to six other similar test stimuli. In a stall, the experimenters mounted a response panel in the doorway. Located on this panel were a response lever and a grain dispenser. The experimenters secured a tactile-stimulus belt to the horse's back. The stimulus belt was constructed by mounting seven solenoids along a piece of burlap in a manner that allowed each to provide the delivery of a tactile stimulus, a repetitive light tapping, at different locations (spaced 10.0 cm apart) along the horse's back. Two preliminary steps were necessary before generalization testing: training a measurable response (lip pressing) and training on several reinforcement schedules in the presence of a training stimulus (tapping by one of the solenoids). We then gave each horse two generalization test sessions. Results indicated that the horses' behavior was effectively controlled by the training stimulus. Horses made the greatest number of responses to the training stimulus, and the tendency to respond to the other test stimuli diminished as the stimuli became farther away from the training stimulus. These findings are discussed in the context of behavioral principles and their relevance to the training of horses.

Compliant tactile sensor for generating a signal related to an applied force

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2012-01-01

Tactile sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector.

Electroencephalographic study showing that tactile stimulation by fabrics of different qualities elicit graded event-related potentials.

PubMed

Hoefer, D; Handel, M; Müller, K-M; Hammer, T R

2016-11-01

Neurophysiologic data on reactions of the human brain towards tactile stimuli evoked by fabrics moved on the skin are scarce. Furthermore, evaluation of fabrics' pleasantness using questionnaires suffers subjective biases. That is why we used a 64-channel electroencephalography (EEG) to objectively evaluate real-time brain reactions to fabric-skin interactions. Tactile stimuli were triggered by selected fabrics of different qualities, i.e. modal/polyamide single jersey, cotton double rib and a jute fabric, applied hidden to either the palm or forearm of 24 subjects via a custom-made fabric-to-skin applicator called SOFIA. One-way anova analysis was carried out to verify the EEG data. The modal/polyamide fabric applied to the forearm and palm led to slightly stronger emotional valence scores in the brain than the conventional or baseline fabric. Furthermore, the single jersey elicits significant higher event-related potential (ERP) signals in all subjects when applied to the forearm, suggesting less distraction and better cognitive resources during the fabric/skin interaction. The brain thus reacts with instantaneous ERP to tactile stimulation of fabrics and is able to discriminate different qualities via implicit preferences. The test procedure described here may be a tool to evaluate the fabric feel with the exclusion of subjective biases. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sustained maintenance of somatotopic information in brain regions recruited by tactile working memory.

PubMed

Katus, Tobias; Müller, Matthias M; Eimer, Martin

2015-01-28

To adaptively guide ongoing behavior, representations in working memory (WM) often have to be modified in line with changing task demands. We used event-related potentials (ERPs) to demonstrate that tactile WM representations are stored in modality-specific cortical regions, that the goal-directed modulation of these representations is mediated through hemispheric-specific activation of somatosensory areas, and that the rehearsal of somatotopic coordinates in memory is accomplished by modality-specific spatial attention mechanisms. Participants encoded two tactile sample stimuli presented simultaneously to the left and right hands, before visual retro-cues indicated which of these stimuli had to be retained to be matched with a subsequent test stimulus on the same hand. Retro-cues triggered a sustained tactile contralateral delay activity component with a scalp topography over somatosensory cortex contralateral to the cued hand. Early somatosensory ERP components to task-irrelevant probe stimuli (that were presented after the retro-cues) and to subsequent test stimuli were enhanced when these stimuli appeared at the currently memorized location relative to other locations on the cued hand, demonstrating that a precise focus of spatial attention was established during the selective maintenance of tactile events in WM. These effects were observed regardless of whether participants performed the matching task with uncrossed or crossed hands, indicating that WM representations in this task were based on somatotopic rather than allocentric spatial coordinates. In conclusion, spatial rehearsal in tactile WM operates within somatotopically organized sensory brain areas that have been recruited for information storage. Copyright © 2015 Katus et al.

Simultaneous Stimulus Preexposure Enhances Human Tactile Perceptual Learning

ERIC Educational Resources Information Center

Rodríguez, Gabriel; Angulo, Rocío

2014-01-01

An experiment with human participants established a novel procedure to assess perceptual learning with tactile stimuli. Participants received unsupervised exposure to two sandpaper surfaces differing in roughness (A and B). The ability of the participants to discriminate between the stimuli was subsequently assessed on a same/different test. It…

The effect of chronic low back pain on tactile suppression during back movements.

PubMed

Van Damme, Stefaan; Van Hulle, Lore; Danneels, Lieven; Spence, Charles; Crombez, Geert

2014-10-01

The aim of the present study was to examine whether tactile suppression, the phenomenon whereby tactile perception is suppressed during movement, would occur in the context of back movements. Of particular interest, it was investigated if tactile suppression in the back would be attenuated in those suffering from chronic low back pain. Individuals with chronic low back pain (N = 30) and a matched control group (N = 24) detected tactile stimuli on three possible locations (back, arm, chest) while performing a back or arm movement, or no movement. We hypothesized that the movements would induce tactile suppression, and that this effect would be largest for low-intense stimuli on the moving body part. We further hypothesized that, during back movements, tactile suppression on the back would be less pronounced in the chronic low back pain group than in the control group. The results showed the expected general tactile suppression effects. The hypothesis of back-specific attenuation of tactile suppression in the chronic low back pain group was not supported. However, back-specific tactile suppression in the chronic low back pain group was less pronounced in those who performed the back movements more slowly. Copyright © 2014 Elsevier B.V. All rights reserved.

Artificial Roughness Encoding with a Bio-inspired MEMS- based Tactile Sensor Array

PubMed Central

Oddo, Calogero Maria; Beccai, Lucia; Felder, Martin; Giovacchini, Francesco; Carrozza, Maria Chiara

2009-01-01

A compliant 2×2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad. PMID:22412304

Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects.

PubMed

Ragert, Patrick; Kalisch, Tobias; Bliem, Barbara; Franzkowiak, Stephanie; Dinse, Hubert R

2008-01-23

Long-term potentiation (LTP) and long-term depression (LTD) play important roles in mediating activity-dependent changes in synaptic transmission and are believed to be crucial mechanisms underlying learning and cortical plasticity. In human subjects, however, the lack of adequate input stimuli for the induction of LTP and LTD makes it difficult to study directly the impact of such protocols on behavior. Using tactile high- and low-frequency stimulation protocols in humans, we explored the potential of such protocols for the induction of perceptual changes. We delivered tactile high-frequency and low-frequency stimuli (t-HFS, t-LFS) to skin sites of approximately 50 mm2 on the tip of the index finger. As assessed by 2-point discrimination, we demonstrate that 20 minutes of t-HFS improved tactile discrimination, while t-LFS impaired performance. T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster. While t-HFS changes were spatially very specific with no changes on the neighboring fingers, impaired tactile performance after t-LFS was also observed on the right middle-finger. A central finding was that for both t-LFS and t-HFS perceptual changes were dependent on the size of the stimulated skin area. No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation. Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

Psychophysical evaluation of a variable friction tactile interface

NASA Astrophysics Data System (ADS)

Samur, Evren; Colgate, J. Edward; Peshkin, Michael A.

2009-02-01

This study explores the haptic rendering capabilities of a variable friction tactile interface through psychophysical experiments. In order to obtain a deeper understanding of the sensory resolution associated with the Tactile Pattern Display (TPaD), friction discrimination experiments are conducted. During the experiments, subjects are asked to explore the glass surface of the TPaD using their bare index fingers, to feel the friction on the surface, and to compare the slipperiness of two stimuli, displayed in sequential order. The fingertip position data is collected by an infrared frame and normal and translational forces applied by the finger are measured by force sensors attached to the TPaD. The recorded data is used to calculate the coefficient of friction between the fingertip and the TPaD. The experiments determine the just noticeable difference (JND) of friction coefficient for humans interacting with the TPaD.

Neural correlates of tactile perception during pre-, peri-, and post-movement.

PubMed

Juravle, Georgiana; Heed, Tobias; Spence, Charles; Röder, Brigitte

2016-05-01

Tactile information is differentially processed over the various phases of goal-directed movements. Here, event-related potentials (ERPs) were used to investigate the neural correlates of tactile and visual information processing during movement. Participants performed goal-directed reaches for an object placed centrally on the table in front of them. Tactile and visual stimulation (100 ms) was presented in separate trials during the different phases of the movement (i.e. preparation, execution, and post-movement). These stimuli were independently delivered to either the moving or resting hand. In a control condition, the participants only performed the movement, while omission (i.e. movement-only) ERPs were recorded. Participants were instructed to ignore the presence or absence of any sensory events and to concentrate solely on the execution of the movement. Enhanced ERPs were observed 80-200 ms after tactile stimulation, as well as 100-250 ms after visual stimulation: These modulations were greatest during the execution of the goal-directed movement, and they were effector based (i.e. significantly more negative for stimuli presented to the moving hand). Furthermore, ERPs revealed enhanced sensory processing during goal-directed movements for visual stimuli as well. Such enhanced processing of both tactile and visual information during the execution phase suggests that incoming sensory information is continuously monitored for a potential adjustment of the current motor plan. Furthermore, the results reported here also highlight a tight coupling between spatial attention and the execution of motor actions.

Integration of auditory and vibrotactile stimuli: Effects of frequency

PubMed Central

Wilson, E. Courtenay; Reed, Charlotte M.; Braida, Louis D.

2010-01-01

Perceptual integration of vibrotactile and auditory sinusoidal tone pulses was studied in detection experiments as a function of stimulation frequency. Vibrotactile stimuli were delivered through a single channel vibrator to the left middle fingertip. Auditory stimuli were presented diotically through headphones in a background of 50 dB sound pressure level broadband noise. Detection performance for combined auditory-tactile presentations was measured using stimulus levels that yielded 63% to 77% correct unimodal performance. In Experiment 1, the vibrotactile stimulus was 250 Hz and the auditory stimulus varied between 125 and 2000 Hz. In Experiment 2, the auditory stimulus was 250 Hz and the tactile stimulus varied between 50 and 400 Hz. In Experiment 3, the auditory and tactile stimuli were always equal in frequency and ranged from 50 to 400 Hz. The highest rates of detection for the combined-modality stimulus were obtained when stimulating frequencies in the two modalities were equal or closely spaced (and within the Pacinian range). Combined-modality detection for closely spaced frequencies was generally consistent with an algebraic sum model of perceptual integration; wider-frequency spacings were generally better fit by a Pythagorean sum model. Thus, perceptual integration of auditory and tactile stimuli at near-threshold levels appears to depend both on absolute frequency and relative frequency of stimulation within each modality. PMID:21117754

Tactile-STAR: A Novel Tactile STimulator And Recorder System for Evaluating and Improving Tactile Perception.

PubMed

Ballardini, Giulia; Carlini, Giorgio; Giannoni, Psiche; Scheidt, Robert A; Nisky, Ilana; Casadio, Maura

2018-01-01

Many neurological diseases impair the motor and somatosensory systems. While several different technologies are used in clinical practice to assess and improve motor functions, somatosensation is evaluated subjectively with qualitative clinical scales. Treatment of somatosensory deficits has received limited attention. To bridge the gap between the assessment and training of motor vs. somatosensory abilities, we designed, developed, and tested a novel, low-cost, two-component (bimanual) mechatronic system targeting tactile somatosensation: the Tactile-STAR -a tactile stimulator and recorder. The stimulator is an actuated pantograph structure driven by two servomotors, with an end-effector covered by a rubber material that can apply two different types of skin stimulation: brush and stretch. The stimulator has a modular design, and can be used to test the tactile perception in different parts of the body such as the hand, arm, leg, big toe, etc. The recorder is a passive pantograph that can measure hand motion using two potentiometers. The recorder can serve multiple purposes: participants can move its handle to match the direction and amplitude of the tactile stimulator, or they can use it as a master manipulator to control the tactile stimulator as a slave. Our ultimate goal is to assess and affect tactile acuity and somatosensory deficits. To demonstrate the feasibility of our novel system, we tested the Tactile-STAR with 16 healthy individuals and with three stroke survivors using the skin-brush stimulation. We verified that the system enables the mapping of tactile perception on the hand in both populations. We also tested the extent to which 30 min of training in healthy individuals led to an improvement of tactile perception. The results provide a first demonstration of the ability of this new system to characterize tactile perception in healthy individuals, as well as a quantification of the magnitude and pattern of tactile impairment in a small cohort of

Does the sight of physical threat induce a tactile processing bias? Modality-specific attentional facilitation induced by viewing threatening pictures.

PubMed

Van Damme, Stefaan; Gallace, Alberto; Spence, Charles; Crombez, Geert; Moseley, G Lorimer

2009-02-09

Threatening stimuli are thought to bias spatial attention toward the location from which the threat is presented. Although this effect is well-established in the visual domain, little is known regarding whether tactile attention is similarly affected by threatening pictures. We hypothesised that tactile attention might be more affected by cues implying physical threat to a person's bodily tissues than by cues implying general threat. In the present study, participants made temporal order judgments (TOJs) concerning which of a pair of tactile (or auditory) stimuli, one presented to either hand, at a range of inter-stimulus intervals, had been presented first. A picture (showing physical threat, general threat, or no threat) was presented in front of one or the other hand shortly before the tactile stimuli. The results revealed that tactile attention was biased toward the side on which the picture was presented, and that this effect was significantly larger for physical threat pictures than for general threat or neutral pictures. By contrast, the bias in auditory attention toward the side of the picture was significantly larger for general threat pictures than for physical threat pictures or neutral pictures. These findings therefore demonstrate a modality-specific effect of physically threatening cues on the processing of tactile stimuli, and of generally threatening cues on auditory information processing. These results demonstrate that the processing of tactile information from the body part closest to the threatening stimulus is prioritized over tactile information from elsewhere on the body.

Functional consequences of experience-dependent plasticity on tactile perception following perceptual learning

PubMed Central

Trzcinski, Natalie K; Gomez-Ramirez, Manuel; Hsiao, Steven S.

2016-01-01

Continuous training enhances perceptual discrimination and promotes neural changes in areas encoding the experienced stimuli. This type of experience-dependent plasticity has been demonstrated in several sensory and motor systems. Particularly, non-human primates trained to detect consecutive tactile bar indentations across multiple digits showed expanded excitatory receptive fields (RFs) in somatosensory cortex. However, the perceptual implications of these anatomical changes remain undetermined. Here, we trained human participants for nine days on a tactile task that promoted expansion of multi-digit RFs. Participants were required to detect consecutive indentations of bar stimuli spanning multiple digits. Throughout the training regime we tracked participants’ discrimination thresholds on spatial (grating orientation) and temporal tasks on the trained and untrained hands in separate sessions. We hypothesized that training on the multi-digit task would decrease perceptual thresholds on tasks that require stimulus processing across multiple digits, while also increasing thresholds on tasks requiring discrimination on single digits. We observed an increase in orientation thresholds on a single-digit. Importantly, this effect was selective for the stimulus orientation and hand used during multi-digit training. We also found that temporal acuity between digits improved across trained digits, suggesting that discriminating the temporal order of multi-digit stimuli can transfer to temporal discrimination of other tactile stimuli. These results suggest that experience-dependent plasticity following perceptual learning improves and interferes with tactile abilities in manners predictive of the task and stimulus features used during training. PMID:27422224

Investigating the mechanisms of visually-evoked tactile sensations.

PubMed

McKenzie, Kirsten J; Lloyd, Donna M; Brown, Richard J; Plummer, Faye; Poliakoff, Ellen

2012-01-01

When attempting to detect a near-threshold signal, participants often incorrectly report the presence of a signal, particularly when a stimulus in a different modality is presented. Here we investigated the effect of prior experience of bimodal visuotactile stimuli on the rate of falsely reported touches in the presence of a light. In Experiment 1, participants made more false alarms in light-present than light-absent trials, despite having no experience of the experimental visuotactile pairing. This suggests that light-evoked false alarms are a consequence of an existing association, rather than one learned during the experiment. In Experiment 2, we sought to manipulate the strength of the association through prior training, using supra-threshold tactile stimuli that were given a high or low association with the light. Both groups still exhibited an increased number of false alarms during light-present trials, however, the low association group made significantly fewer false alarms across conditions, and there was no corresponding group difference in the number of tactile stimuli correctly identified. Thus, while training did not affect the boosting of the tactile signal by the visual stimulus, the low association training affected perceptual decision-making more generally, leading to a lower number of illusory touch reports, independent of the light. Copyright © 2011 Elsevier B.V. All rights reserved.

Tactile information transfer: A comparison of two stimulation sites

NASA Astrophysics Data System (ADS)

Summers, Ian R.; Whybrow, Jon J.; Gratton, Denise A.; Milnes, Peter; Brown, Brian H.; Stevens, John C.

2005-10-01

Two experiments on the discrimination of time-varying tactile stimuli were performed, with comparison of stimulus delivery to the distal pad of the right index finger and to the right wrist (palmar surface). Subjects were required to perceive differences in short sequences of computer-generated stimulus elements (experiment 1) or differences in short tactile stimuli derived from a speech signal (experiment 2). The pulse-train stimuli were distinguished by differences in frequency (i.e., pulse repetition rate) and amplitude, and by the presence/absence of gaps (~100-ms duration). Stimulation levels were 10 dB higher at the wrist than at the fingertip, to compensate for the lower vibration sensitivity at the wrist. Results indicate similar gap detection at wrist and fingertip and similar perception of frequency differences. However, perception of amplitude differences was found to be better at the wrist than at the fingertip. Maximum information transfer rates for the stimuli in experiment 1 were estimated at 7 bits s-1 at the wrist and 5 bits s-1 at the fingertip.

Tactile information transfer: a comparison of two stimulation sites.

PubMed

Summers, lan R; Whybrow, Jon J; Gratton, Denise A; Milnes, Peter; Brown, Brian H; Stevens, John C

2005-10-01

Two experiments on the discrimination of time-varying tactile stimuli were performed, with comparison of stimulus delivery to the distal pad of the right index finger and to the right wrist (palmar surface). Subjects were required to perceive differences in short sequences of computer-generated stimulus elements (experiment 1) or differences in short tactile stimuli derived from a speech signal (experiment 2). The pulse-train stimuli were distinguished by differences in frequency (i.e., pulse repetition rate) and amplitude, and by the presence/absence of gaps (approximately 100-ms duration). Stimulation levels were 10 dB higher at the wrist than at the fingertip, to compensate for the lower vibration sensitivity at the wrist. Results indicate similar gap detection at wrist and fingertip and similar perception of frequency differences. However, perception of amplitude differences was found to be better at the wrist than at the fingertip. Maximum information transfer rates for the stimuli in experiment 1 were estimated at 7 bits s(-1) at the wrist and 5 bits s(-1) at the fingertip.

A long-lasting improvement of tactile extinction after galvanic vestibular stimulation: two Sham-stimulation controlled case studies.

PubMed

Kerkhoff, Georg; Hildebrandt, Helmut; Reinhart, Stefan; Kardinal, Mareike; Dimova, Violeta; Utz, Kathrin S

2011-01-01

Sensory extinction is frequent and often persistent after brain damage. Previous studies have shown the transient influence of sensory stimulation on tactile extinction. In the present two case studies we investigated whether subliminal galvanic vestibular stimulation (GVS) modulates tactile extinction. GVS induces polarity-specific changes in cerebral excitability in the vestibular cortices and adjacent cortical areas in the temporo-parietal cortex via polarization of the vestibular nerves. Two patients (DL, CJ) with left-sided tactile extinction due to chronic (5 vs. 6 (1/2) years lesion age) right-hemisphere lesions (right fronto-parietal in DL, right frontal and discrete parietal in CJ) were examined. Both showed normal tactile sensitivity to light touch and yielded 90-100% correct identifications in unilateral tactile stimulations for both hands. In Baseline investigations without GVS and Sham-GVS both showed stable left-sided tactile extinction rates of 40-55% (DL) and 49-72% (CJ). In contrast, one session of right-cathodal GVS (intensity: 0.6 mA, duration: 20 min) permanently improved tactile identification of identical stimuli, while a second session with left-cathodal GVS significantly reduced left-sided extinction rates for different stimuli in DL. Patient CJ's left-sided tactile extinction was significantly improved by left-cathodal GVS (0.5 mA, 20 min) for different stimuli, while right-cathodal GVS induced a significant reduction for identical materials. In contrast, Sham-stimulation was ineffective. Improvements remained stable for at least 1 year (DL) resp. 3 weeks (CJ). Control experiments ruled out improvements in tactile extinction merely by retesting. In conclusion, chronic tactile extinction may be permanently improved by GVS in a polarity-specific way. Copyright © 2010 Elsevier Ltd. All rights reserved.

Hearing shapes our perception of time: temporal discrimination of tactile stimuli in deaf people.

PubMed

Bolognini, Nadia; Cecchetto, Carlo; Geraci, Carlo; Maravita, Angelo; Pascual-Leone, Alvaro; Papagno, Costanza

2012-02-01

Confronted with the loss of one type of sensory input, we compensate using information conveyed by other senses. However, losing one type of sensory information at specific developmental times may lead to deficits across all sensory modalities. We addressed the effect of auditory deprivation on the development of tactile abilities, taking into account changes occurring at the behavioral and cortical level. Congenitally deaf and hearing individuals performed two tactile tasks, the first requiring the discrimination of the temporal duration of touches and the second requiring the discrimination of their spatial length. Compared with hearing individuals, deaf individuals were impaired only in tactile temporal processing. To explore the neural substrate of this difference, we ran a TMS experiment. In deaf individuals, the auditory association cortex was involved in temporal and spatial tactile processing, with the same chronometry as the primary somatosensory cortex. In hearing participants, the involvement of auditory association cortex occurred at a later stage and selectively for temporal discrimination. The different chronometry in the recruitment of the auditory cortex in deaf individuals correlated with the tactile temporal impairment. Thus, early hearing experience seems to be crucial to develop an efficient temporal processing across modalities, suggesting that plasticity does not necessarily result in behavioral compensation.

Functional consequences of experience-dependent plasticity on tactile perception following perceptual learning.

PubMed

Trzcinski, Natalie K; Gomez-Ramirez, Manuel; Hsiao, Steven S

2016-09-01

Continuous training enhances perceptual discrimination and promotes neural changes in areas encoding the experienced stimuli. This type of experience-dependent plasticity has been demonstrated in several sensory and motor systems. Particularly, non-human primates trained to detect consecutive tactile bar indentations across multiple digits showed expanded excitatory receptive fields (RFs) in somatosensory cortex. However, the perceptual implications of these anatomical changes remain undetermined. Here, we trained human participants for 9 days on a tactile task that promoted expansion of multi-digit RFs. Participants were required to detect consecutive indentations of bar stimuli spanning multiple digits. Throughout the training regime we tracked participants' discrimination thresholds on spatial (grating orientation) and temporal tasks on the trained and untrained hands in separate sessions. We hypothesized that training on the multi-digit task would decrease perceptual thresholds on tasks that require stimulus processing across multiple digits, while also increasing thresholds on tasks requiring discrimination on single digits. We observed an increase in orientation thresholds on a single digit. Importantly, this effect was selective for the stimulus orientation and hand used during multi-digit training. We also found that temporal acuity between digits improved across trained digits, suggesting that discriminating the temporal order of multi-digit stimuli can transfer to temporal discrimination of other tactile stimuli. These results suggest that experience-dependent plasticity following perceptual learning improves and interferes with tactile abilities in manners predictive of the task and stimulus features used during training. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

An Examination of the Potential for Blissymbolics to Serve as the Foundation for a Tactile Symbol System

ERIC Educational Resources Information Center

Isaacson, Mickey

2012-01-01

The primary purpose of this study was to determine whether Blissymbolics have the potential for being developed into a tactile symbol communication system. Tactile techniques are used by many individuals with augmentative and alternative communication (AAC) needs. Tactile processing is optimized by the use of minimalistic stimuli, i.e., stimuli…

TACTILE RESPONSIVENESS PATTERNS AND THEIR ASSOCIATION WITH CORE FEATURES IN AUTISM SPECTRUM DISORDERS

PubMed Central

Foss-Feig, Jennifer H.; Heacock, Jessica L.; Cascio, Carissa J.

2011-01-01

Autism spectrum disorders (ASD) are often associated with aberrant responses to sensory stimuli, which are thought to contribute to the social, communication, and repetitive behavior deficits that define ASD. However, there are few studies that separate aberrant sensory responses by individual sensory modality to assess modality-specific associations between sensory features and core symptoms. Differences in response to tactile stimuli are prevalent in ASD, and tactile contact early in infancy is a foundation for the development of social and communication skills affected by ASD. We assessed the association between three aberrant patterns of tactile responsiveness (hyper-responsiveness, hypo-responsiveness, sensory seeking) and core symptoms of ASD. Both sensory and core features were measured with converging methods including both parent-report and direct observation. Our results demonstrate that for the tactile modality, sensory hypo-responsiveness correlates strongly with increased social and communication impairments, and to a lesser degree, repetitive behaviors. Sensory seeking was found to correlate strongly with social impairment, nonverbal communication impairment, and repetitive behaviors. Surprisingly, tactile hyper-responsiveness did not significantly correlate with any core features of ASD. This differential association between specific tactile processing patterns and core features provides an important step in defining the significance of sensory symptoms in ASD, and may be useful in the development of sensory–based approaches for early detection and intervention. PMID:22059092

Neural Activity Patterns in the Human Brain Reflect Tactile Stickiness Perception.

PubMed

Kim, Junsuk; Yeon, Jiwon; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

2017-01-01

Our previous human fMRI study found brain activations correlated with tactile stickiness perception using the uni-variate general linear model (GLM) (Yeon et al., 2017). Here, we conducted an in-depth investigation on neural correlates of sticky sensations by employing a multivoxel pattern analysis (MVPA) on the same dataset. In particular, we statistically compared multi-variate neural activities in response to the three groups of sticky stimuli: A supra-threshold group including a set of sticky stimuli that evoked vivid sticky perception; an infra-threshold group including another set of sticky stimuli that barely evoked sticky perception; and a sham group including acrylic stimuli with no physically sticky property. Searchlight MVPAs were performed to search for local activity patterns carrying neural information of stickiness perception. Similar to the uni-variate GLM results, significant multi-variate neural activity patterns were identified in postcentral gyrus, subcortical (basal ganglia and thalamus), and insula areas (insula and adjacent areas). Moreover, MVPAs revealed that activity patterns in posterior parietal cortex discriminated the perceptual intensities of stickiness, which was not present in the uni-variate analysis. Next, we applied a principal component analysis (PCA) to the voxel response patterns within identified clusters so as to find low-dimensional neural representations of stickiness intensities. Follow-up clustering analyses clearly showed separate neural grouping configurations between the Supra- and Infra-threshold groups. Interestingly, this neural categorization was in line with the perceptual grouping pattern obtained from the psychophysical data. Our findings thus suggest that different stickiness intensities would elicit distinct neural activity patterns in the human brain and may provide a neural basis for the perception and categorization of tactile stickiness.

Neural Activity Patterns in the Human Brain Reflect Tactile Stickiness Perception

PubMed Central

Kim, Junsuk; Yeon, Jiwon; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

2017-01-01

Our previous human fMRI study found brain activations correlated with tactile stickiness perception using the uni-variate general linear model (GLM) (Yeon et al., 2017). Here, we conducted an in-depth investigation on neural correlates of sticky sensations by employing a multivoxel pattern analysis (MVPA) on the same dataset. In particular, we statistically compared multi-variate neural activities in response to the three groups of sticky stimuli: A supra-threshold group including a set of sticky stimuli that evoked vivid sticky perception; an infra-threshold group including another set of sticky stimuli that barely evoked sticky perception; and a sham group including acrylic stimuli with no physically sticky property. Searchlight MVPAs were performed to search for local activity patterns carrying neural information of stickiness perception. Similar to the uni-variate GLM results, significant multi-variate neural activity patterns were identified in postcentral gyrus, subcortical (basal ganglia and thalamus), and insula areas (insula and adjacent areas). Moreover, MVPAs revealed that activity patterns in posterior parietal cortex discriminated the perceptual intensities of stickiness, which was not present in the uni-variate analysis. Next, we applied a principal component analysis (PCA) to the voxel response patterns within identified clusters so as to find low-dimensional neural representations of stickiness intensities. Follow-up clustering analyses clearly showed separate neural grouping configurations between the Supra- and Infra-threshold groups. Interestingly, this neural categorization was in line with the perceptual grouping pattern obtained from the psychophysical data. Our findings thus suggest that different stickiness intensities would elicit distinct neural activity patterns in the human brain and may provide a neural basis for the perception and categorization of tactile stickiness. PMID:28936171

Learning touch preferences with a tactile robot using dopamine modulated STDP in a model of insular cortex

PubMed Central

Chou, Ting-Shuo; Bucci, Liam D.; Krichmar, Jeffrey L.

2015-01-01

Neurorobots enable researchers to study how behaviors are produced by neural mechanisms in an uncertain, noisy, real-world environment. To investigate how the somatosensory system processes noisy, real-world touch inputs, we introduce a neurorobot called CARL-SJR, which has a full-body tactile sensory area. The design of CARL-SJR is such that it encourages people to communicate with it through gentle touch. CARL-SJR provides feedback to users by displaying bright colors on its surface. In the present study, we show that CARL-SJR is capable of learning associations between conditioned stimuli (CS; a color pattern on its surface) and unconditioned stimuli (US; a preferred touch pattern) by applying a spiking neural network (SNN) with neurobiologically inspired plasticity. Specifically, we modeled the primary somatosensory cortex, prefrontal cortex, striatum, and the insular cortex, which is important for hedonic touch, to process noisy data generated directly from CARL-SJR's tactile sensory area. To facilitate learning, we applied dopamine-modulated Spike Timing Dependent Plasticity (STDP) to our simulated prefrontal cortex, striatum, and insular cortex. To cope with noisy, varying inputs, the SNN was tuned to produce traveling waves of activity that carried spatiotemporal information. Despite the noisy tactile sensors, spike trains, and variations in subject hand swipes, the learning was quite robust. Further, insular cortex activities in the incremental pathway of dopaminergic reward system allowed us to control CARL-SJR's preference for touch direction without heavily pre-processed inputs. The emerged behaviors we found in this model match animal's behaviors wherein they prefer touch in particular areas and directions. Thus, the results in this paper could serve as an explanation on the underlying neural mechanisms for developing tactile preferences and hedonic touch. PMID:26257639

Anterior insula coordinates hierarchical processing of tactile mismatch responses

PubMed Central

Allen, Micah; Fardo, Francesca; Dietz, Martin J.; Hillebrandt, Hauke; Friston, Karl J.; Rees, Geraint; Roepstorff, Andreas

2016-01-01

The body underlies our sense of self, emotion, and agency. Signals arising from the skin convey warmth, social touch, and the physical characteristics of external stimuli. Surprising or unexpected tactile sensations can herald events of motivational salience, including imminent threats (e.g., an insect bite) and hedonic rewards (e.g., a caressing touch). Awareness of such events is thought to depend upon the hierarchical integration of body-related mismatch responses by the anterior insula. To investigate this possibility, we measured brain activity using functional magnetic resonance imaging, while healthy participants performed a roving tactile oddball task. Mass-univariate analysis demonstrated robust activations in limbic, somatosensory, and prefrontal cortical areas previously implicated in tactile deviancy, body awareness, and cognitive control. Dynamic Causal Modelling revealed that unexpected stimuli increased the strength of forward connections along a caudal to rostral hierarchy—projecting from thalamic and somatosensory regions towards insula, cingulate and prefrontal cortices. Within this ascending flow of sensory information, the AIC was the only region to show increased backwards connectivity to the somatosensory cortex, augmenting a reciprocal exchange of neuronal signals. Further, participants who rated stimulus changes as easier to detect showed stronger modulation of descending PFC to AIC connections by deviance. These results suggest that the AIC coordinates hierarchical processing of tactile prediction error. They are interpreted in support of an embodied predictive coding model where AIC mediated body awareness is involved in anchoring a global neuronal workspace. PMID:26584870

Differences in Early Stages of Tactile ERP Temporal Sequence (P100) in Cortical Organization during Passive Tactile Stimulation in Children with Blindness and Controls.

PubMed

Ortiz Alonso, Tomás; Santos, Juan Matías; Ortiz Terán, Laura; Borrego Hernández, Mayelin; Poch Broto, Joaquín; de Erausquin, Gabriel Alejandro

2015-01-01

Compared to their seeing counterparts, people with blindness have a greater tactile capacity. Differences in the physiology of object recognition between people with blindness and seeing people have been well documented, but not when tactile stimuli require semantic processing. We used a passive vibrotactile device to focus on the differences in spatial brain processing evaluated with event related potentials (ERP) in children with blindness (n = 12) vs. normally seeing children (n = 12), when learning a simple spatial task (lines with different orientations) or a task involving recognition of letters, to describe the early stages of its temporal sequence (from 80 to 220 msec) and to search for evidence of multi-modal cortical organization. We analysed the P100 of the ERP. Children with blindness showed earlier latencies for cognitive (perceptual) event related potentials, shorter reaction times, and (paradoxically) worse ability to identify the spatial direction of the stimulus. On the other hand, they are equally proficient in recognizing stimuli with semantic content (letters). The last observation is consistent with the role of P100 on somatosensory-based recognition of complex forms. The cortical differences between seeing control and blind groups, during spatial tactile discrimination, are associated with activation in visual pathway (occipital) and task-related association (temporal and frontal) areas. The present results show that early processing of tactile stimulation conveying cross modal information differs in children with blindness or with normal vision.

Differences in Early Stages of Tactile ERP Temporal Sequence (P100) in Cortical Organization during Passive Tactile Stimulation in Children with Blindness and Controls

PubMed Central

Ortiz Alonso, Tomás; Santos, Juan Matías; Ortiz Terán, Laura; Borrego Hernández, Mayelin; Poch Broto, Joaquín; de Erausquin, Gabriel Alejandro

2015-01-01

Compared to their seeing counterparts, people with blindness have a greater tactile capacity. Differences in the physiology of object recognition between people with blindness and seeing people have been well documented, but not when tactile stimuli require semantic processing. We used a passive vibrotactile device to focus on the differences in spatial brain processing evaluated with event related potentials (ERP) in children with blindness (n = 12) vs. normally seeing children (n = 12), when learning a simple spatial task (lines with different orientations) or a task involving recognition of letters, to describe the early stages of its temporal sequence (from 80 to 220 msec) and to search for evidence of multi-modal cortical organization. We analysed the P100 of the ERP. Children with blindness showed earlier latencies for cognitive (perceptual) event related potentials, shorter reaction times, and (paradoxically) worse ability to identify the spatial direction of the stimulus. On the other hand, they are equally proficient in recognizing stimuli with semantic content (letters). The last observation is consistent with the role of P100 on somatosensory-based recognition of complex forms. The cortical differences between seeing control and blind groups, during spatial tactile discrimination, are associated with activation in visual pathway (occipital) and task-related association (temporal and frontal) areas. The present results show that early processing of tactile stimulation conveying cross modal information differs in children with blindness or with normal vision. PMID:26225827

Change of reference frame for tactile localization during child development.

PubMed

Pagel, Birthe; Heed, Tobias; Röder, Brigitte

2009-11-01

Temporal order judgements (TOJ) for two tactile stimuli, one presented to the left and one to the right hand, are less precise when the hands are crossed over the midline than when the hands are uncrossed. This 'crossed hand' effect has been considered as evidence for a remapping of tactile input into an external reference frame. Since late, but not early, blind individuals show such remapping, it has been hypothesized that the use of an external reference frame develops during childhood. Five- to 10-year-old children were therefore tested with the tactile TOJ task, both with uncrossed and crossed hands. Overall performance in the TOJ task improved with age. While children older than 5 1/2 years displayed a crossed hand effect, younger children did not. Therefore the use of an external reference frame for tactile, and possibly multisensory, localization seems to be acquired at age 5.

Tactile mental body parts representation in obesity.

PubMed

Scarpina, Federica; Castelnuovo, Gianluca; Molinari, Enrico

2014-12-30

Obese people׳s distortions in visually-based mental body-parts representations have been reported in previous studies, but other sensory modalities have largely been neglected. In the present study, we investigated possible differences in tactilely-based body-parts representation between an obese and a healthy-weight group; additionally we explore the possible relationship between the tactile- and the visually-based body representation. Participants were asked to estimate the distance between two tactile stimuli that were simultaneously administered on the arm or on the abdomen, in the absence of visual input. The visually-based body-parts representation was investigated by a visual imagery method in which subjects were instructed to compare the horizontal extension of body part pairs. According to the results, the obese participants overestimated the size of the tactilely-perceived distances more than the healthy-weight group when the arm, and not the abdomen, was stimulated. Moreover, they reported a lower level of accuracy than did the healthy-weight group when estimating horizontal distances relative to their bodies, confirming an inappropriate visually-based mental body representation. Our results imply that body representation disturbance in obese people is not limited to the visual mental domain, but it spreads to the tactilely perceived distances. The inaccuracy was not a generalized tendency but was body-part related. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Abnormal tactile temporal discrimination in psychogenic dystonia.

PubMed

Morgante, F; Tinazzi, M; Squintani, G; Martino, D; Defazio, G; Romito, L; Albanese, A; Di Matteo, A; Quartarone, A; Girlanda, P; Fiorio, M; Berardelli, A

2011-09-20

Neurophysiologic studies demonstrated that patients with primary torsion dystonia (PTD) and with psychogenic dystonia (Psy-D) share similar abnormalities in the motor system. In this study, we evaluated somatosensory function in Psy-D by testing temporal discrimination threshold (TDT), and compared the results with those obtained in patients with PTD. TDT of tactile stimuli was assessed in 10 patients with Psy-D, 10 patients with PTD, and 16 control subjects. The 2 groups of patients were matched for age, gender, disease duration, and distribution of dystonia. Tactile stimuli consisted of pairs of non-noxious electrical shocks delivered to the right or left hand at interstimulus interval increasing from 0 to 400 msec, in 10-msec steps. TDT was defined as the value at which subjects recognized the 2 stimuli as asynchronous. TDT was higher in Psy-D and PTD compared to control subjects, for both the right and the left hand. In a subgroup of patients with unilateral dystonia (Psy-D = 4, PTD = 5), TDT did not differ between the affected and the unaffected side in both groups of patients. Disease duration was not correlated to the increased TDT value. Our study suggests an impaired processing of somatosensory inputs in both Psy-D and PTD. These abnormalities might represent a neurophysiological trait predisposing to develop a dystonic posture triggered by psychiatric and psychological factors.

Cortical Merging in S1 as a Substrate for Tactile Input Grouping

PubMed Central

Zennou-Azogui, Yoh’I; Xerri, Christian

2018-01-01

Abstract Perception is a reconstruction process guided by rules based on knowledge about the world. Little is known about the neural implementation of the rules of object formation in the tactile sensory system. When two close tactile stimuli are delivered simultaneously on the skin, subjects feel a unique sensation, spatially centered between the two stimuli. Voltage-sensitive dye imaging (VSDi) and electrophysiological recordings [local field potentials (LFPs) and single units] were used to extract the cortical representation of two-point tactile stimuli in the primary somatosensory cortex of anesthetized Long-Evans rats. Although layer 4 LFP responses to brief costimulation of the distal region of two digits resembled the sum of individual responses, approximately one-third of single units demonstrated merging-compatible changes. In contrast to previous intrinsic optical imaging studies, VSD activations reflecting layer 2/3 activity were centered between the representations of the digits stimulated alone. This merging was found for every tested distance between the stimulated digits. We discuss this laminar difference as evidence that merging occurs through a buildup stream and depends on the superposition of inputs, which increases with successive stages of sensory processing. These findings show that layers 2/3 are involved in the grouping of sensory inputs. This process that could be inscribed in the cortical computing routine and network organization is likely to promote object formation and implement perception rules. PMID:29354679

Audio-Tactile Integration in Congenitally and Late Deaf Cochlear Implant Users

PubMed Central

Nava, Elena; Bottari, Davide; Villwock, Agnes; Fengler, Ineke; Büchner, Andreas; Lenarz, Thomas; Röder, Brigitte

2014-01-01

Several studies conducted in mammals and humans have shown that multisensory processing may be impaired following congenital sensory loss and in particular if no experience is achieved within specific early developmental time windows known as sensitive periods. In this study we investigated whether basic multisensory abilities are impaired in hearing-restored individuals with deafness acquired at different stages of development. To this aim, we tested congenitally and late deaf cochlear implant (CI) recipients, age-matched with two groups of hearing controls, on an audio-tactile redundancy paradigm, in which reaction times to unimodal and crossmodal redundant signals were measured. Our results showed that both congenitally and late deaf CI recipients were able to integrate audio-tactile stimuli, suggesting that congenital and acquired deafness does not prevent the development and recovery of basic multisensory processing. However, we found that congenitally deaf CI recipients had a lower multisensory gain compared to their matched controls, which may be explained by their faster responses to tactile stimuli. We discuss this finding in the context of reorganisation of the sensory systems following sensory loss and the possibility that these changes cannot be “rewired” through auditory reafferentation. PMID:24918766

Audio-tactile integration in congenitally and late deaf cochlear implant users.

PubMed

Nava, Elena; Bottari, Davide; Villwock, Agnes; Fengler, Ineke; Büchner, Andreas; Lenarz, Thomas; Röder, Brigitte

2014-01-01

Several studies conducted in mammals and humans have shown that multisensory processing may be impaired following congenital sensory loss and in particular if no experience is achieved within specific early developmental time windows known as sensitive periods. In this study we investigated whether basic multisensory abilities are impaired in hearing-restored individuals with deafness acquired at different stages of development. To this aim, we tested congenitally and late deaf cochlear implant (CI) recipients, age-matched with two groups of hearing controls, on an audio-tactile redundancy paradigm, in which reaction times to unimodal and crossmodal redundant signals were measured. Our results showed that both congenitally and late deaf CI recipients were able to integrate audio-tactile stimuli, suggesting that congenital and acquired deafness does not prevent the development and recovery of basic multisensory processing. However, we found that congenitally deaf CI recipients had a lower multisensory gain compared to their matched controls, which may be explained by their faster responses to tactile stimuli. We discuss this finding in the context of reorganisation of the sensory systems following sensory loss and the possibility that these changes cannot be "rewired" through auditory reafferentation.

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Tactile modulation of hippocampal place fields.

PubMed

Gener, Thomas; Perez-Mendez, Lorena; Sanchez-Vives, Maria V

2013-12-01

Neural correlates of spatial representation can be found in the activity of the hippocampal place cells. These neurons are characterized by firing whenever the animal is located in a particular area of the space, the place field. Place fields are modulated by sensory cues, such as visual, auditory, or olfactory cues, being the influence of visual inputs the most thoroughly studied. Tactile information gathered by the whiskers has a prominent representation in the rat cerebral cortex. However, the influence of whisker-detected tactile cues on place fields remains an open question. Here we studied place fields in an enriched tactile environment where the remaining sensory cues were occluded. First, place cells were recorded before and after blockade of tactile transmission by means of lidocaine applied on the whisker pad. Following tactile deprivation, the majority of place cells decreased their firing rate and their place fields expanded. We next rotated the tactile cues and 90% of place fields rotated with them. Our results demonstrate that tactile information is integrated into place cells at least in a tactile-enriched arena and when other sensory cues are not available. Copyright © 2013 Wiley Periodicals, Inc.

Mapping the human brain during a specific Vojta's tactile input: the ipsilateral putamen's role.

PubMed

Sanz-Esteban, Ismael; Calvo-Lobo, Cesar; Ríos-Lago, Marcos; Álvarez-Linera, Juan; Muñoz-García, Daniel; Rodríguez-Sanz, David

2018-03-01

A century of research in human brain parcellation has demonstrated that different brain areas are associated with functional tasks. New neuroscientist perspectives to achieve the parcellation of the human brain have been developed to know the brain areas activation and its relationship with different stimuli. This descriptive study aimed to compare brain regions activation by specific tactile input (STI) stimuli according to the Vojta protocol (STI-group) to a non-STI stimulation (non-STI-group). An exploratory functional magnetic resonance imaging (fMRI) study was performed. The 2 groups of participants were passively stimulated by an expert physical therapist using the same paradigm structure, although differing in the place of stimulation. The stimulation was presented to participants using a block design in all cases. A sample of 16 healthy participants, 5 men and 11 women, with mean age 31.31 ± 8.13 years was recruited. Indeed, 12 participants were allocated in the STI-group and 4 participants in the non-STI-group. fMRI was used to map the human brain in vivo while these tactile stimuli were being applied. Data were analyzed using a general linear model in SPM12 implemented in MATLAB. Differences between groups showed a greater activation in the right cortical areas (temporal and frontal lobes), subcortical regions (thalamus, brainstem, and basal nuclei), and in the cerebellum (anterior lobe). STI-group had specific difference brain activation areas, such as the ipsilateral putamen. Future studies should study clinical implications in neurorehabilitation patients.

Mapping the human brain during a specific Vojta's tactile input: the ipsilateral putamen's role

PubMed Central

Sanz-Esteban, Ismael; Calvo-Lobo, Cesar; Ríos-Lago, Marcos; Álvarez-Linera, Juan; Muñoz-García, Daniel; Rodríguez-Sanz, David

2018-01-01

Abstract A century of research in human brain parcellation has demonstrated that different brain areas are associated with functional tasks. New neuroscientist perspectives to achieve the parcellation of the human brain have been developed to know the brain areas activation and its relationship with different stimuli. This descriptive study aimed to compare brain regions activation by specific tactile input (STI) stimuli according to the Vojta protocol (STI-group) to a non-STI stimulation (non-STI-group). An exploratory functional magnetic resonance imaging (fMRI) study was performed. The 2 groups of participants were passively stimulated by an expert physical therapist using the same paradigm structure, although differing in the place of stimulation. The stimulation was presented to participants using a block design in all cases. A sample of 16 healthy participants, 5 men and 11 women, with mean age 31.31 ± 8.13 years was recruited. Indeed, 12 participants were allocated in the STI-group and 4 participants in the non-STI-group. fMRI was used to map the human brain in vivo while these tactile stimuli were being applied. Data were analyzed using a general linear model in SPM12 implemented in MATLAB. Differences between groups showed a greater activation in the right cortical areas (temporal and frontal lobes), subcortical regions (thalamus, brainstem, and basal nuclei), and in the cerebellum (anterior lobe). STI-group had specific difference brain activation areas, such as the ipsilateral putamen. Future studies should study clinical implications in neurorehabilitation patients. PMID:29595683

Virtual surface characteristics of a tactile display using magneto-rheological fluids.

PubMed

Lee, Chul-Hee; Jang, Min-Gyu

2011-01-01

Virtual surface characteristics of tactile displays are investigated to characterize the feeling of human touch for a haptic interface application. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, friction, and topography of the surface. Thus, the tactile display can provide information on the surface of an organic tissue to the surgeon in virtual reality. In order to investigate the compliance feeling of a human finger's touch, normal force responses of a tactile display under various magnetic fields have been assessed. Also, shearing friction force responses of the tactile display are investigated to simulate the action of finger dragging on the surface. Moreover, different matrix arrays of magnetic poles are applied to form the virtual surface topography. From the results, different tactile feelings are observed according to the applied magnetic field strength as well as the arrays of magnetic poles combinations. This research presents a smart tactile display technology for virtual surfaces.

Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices.

PubMed

Mun, Seongcheol; Yun, Sungryul; Nam, Saekwang; Park, Seung Koo; Park, Suntak; Park, Bong Je; Lim, Jeong Mook; Kyung, Ki-Uk

2018-01-01

This paper reports soft actuator based tactile stimulation interfaces applicable to wearable devices. The soft actuator is prepared by multi-layered accumulation of thin electro-active polymer (EAP) films. The multi-layered actuator is designed to produce electrically-induced convex protrusive deformation, which can be dynamically programmable for wide range of tactile stimuli. The maximum vertical protrusion is and the output force is up to 255 mN. The soft actuators are embedded into the fingertip part of a glove and front part of a forearm band, respectively. We have conducted two kinds of experiments with 15 subjects. Perceived magnitudes of actuator's protrusion and vibrotactile intensity were measured with frequency of 1 Hz and 191 Hz, respectively. Analysis of the user tests shows participants perceive variation of protrusion height at the finger pad and modulation of vibration intensity through the proposed soft actuator based tactile interface.

Interaction of Perceptual Grouping and Crossmodal Temporal Capture in Tactile Apparent-Motion

PubMed Central

Chen, Lihan; Shi, Zhuanghua; Müller, Hermann J.

2011-01-01

Previous studies have shown that in tasks requiring participants to report the direction of apparent motion, task-irrelevant mono-beeps can “capture” visual motion perception when the beeps occur temporally close to the visual stimuli. However, the contributions of the relative timing of multimodal events and the event structure, modulating uni- and/or crossmodal perceptual grouping, remain unclear. To examine this question and extend the investigation to the tactile modality, the current experiments presented tactile two-tap apparent-motion streams, with an SOA of 400 ms between successive, left-/right-hand middle-finger taps, accompanied by task-irrelevant, non-spatial auditory stimuli. The streams were shown for 90 seconds, and participants' task was to continuously report the perceived (left- or rightward) direction of tactile motion. In Experiment 1, each tactile stimulus was paired with an auditory beep, though odd-numbered taps were paired with an asynchronous beep, with audiotactile SOAs ranging from −75 ms to 75 ms. Perceived direction of tactile motion varied systematically with audiotactile SOA, indicative of a temporal-capture effect. In Experiment 2, two audiotactile SOAs—one short (75 ms), one long (325 ms)—were compared. The long-SOA condition preserved the crossmodal event structure (so the temporal-capture dynamics should have been similar to that in Experiment 1), but both beeps now occurred temporally close to the taps on one side (even-numbered taps). The two SOAs were found to produce opposite modulations of apparent motion, indicative of an influence of crossmodal grouping. In Experiment 3, only odd-numbered, but not even-numbered, taps were paired with auditory beeps. This abolished the temporal-capture effect and, instead, a dominant percept of apparent motion from the audiotactile side to the tactile-only side was observed independently of the SOA variation. These findings suggest that asymmetric crossmodal grouping leads to an

To What Extent Do Gestalt Grouping Principles Influence Tactile Perception?

ERIC Educational Resources Information Center

Gallace, Alberto; Spence, Charles

2011-01-01

Since their formulation by the Gestalt movement more than a century ago, the principles of perceptual grouping have primarily been investigated in the visual modality and, to a lesser extent, in the auditory modality. The present review addresses the question of whether the same grouping principles also affect the perception of tactile stimuli.…

Merkel disc is a serotonergic synapse in the epidermis for transmitting tactile signals in mammals.

PubMed

Chang, Weipang; Kanda, Hirosato; Ikeda, Ryo; Ling, Jennifer; DeBerry, Jennifer J; Gu, Jianguo G

2016-09-13

The evolution of sensory systems has let mammals develop complicated tactile end organs to enable sophisticated sensory tasks, including social interaction, environmental exploration, and tactile discrimination. The Merkel disc, a main type of tactile end organ consisting of Merkel cells (MCs) and Aβ-afferent endings, are highly abundant in fingertips, touch domes, and whisker hair follicles of mammals. The Merkel disc has high tactile acuity for an object's physical features, such as texture, shape, and edges. Mechanisms underlying the tactile function of Merkel discs are obscured as to how MCs transmit tactile signals to Aβ-afferent endings leading to tactile sensations. Using mouse whisker hair follicles, we show herein that tactile stimuli are transduced by MCs into excitatory signals that trigger vesicular serotonin release from MCs. We identify that both ionotropic and metabotropic 5-hydroxytryptamine (5-HT) receptors are expressed on whisker Aβ-afferent endings and that their activation by serotonin released from MCs initiates Aβ-afferent impulses. Moreover, we demonstrate that these ionotropic and metabotropic 5-HT receptors have a synergistic effect that is critical to both electrophysiological and behavioral tactile responses. These findings elucidate that the Merkel disc is a unique serotonergic synapse located in the epidermis and plays a key role in tactile transmission. The epidermal serotonergic synapse may have important clinical implications in sensory dysfunctions, such as the loss of tactile sensitivity and tactile allodynia seen in patients who have diabetes, inflammatory diseases, and undergo chemotherapy. It may also have implications in the exaggerated tactile sensations induced by recreational drugs that act on serotoninergic synapses.

When Seeing Doesn't Matter: Assessing the After-Effects of Tactile Distractor Processing in the Blind and the Sighted

ERIC Educational Resources Information Center

Frings, Christian; Amendt, Anna; Spence, Charles

2011-01-01

Negative priming (NP) refers to the finding that people's responses to probe targets previously presented as prime distractors are usually slower than to unrepeated stimuli. Intriguingly, the effect sizes of tactile NP were much larger than the effect sizes for visual NP. We analyzed whether the large tactile NP effect is just a side effect of the…

Tactile stimulation and hemispheric asymmetries modulate auditory perception and neural responses in primary auditory cortex.

PubMed

Hoefer, M; Tyll, S; Kanowski, M; Brosch, M; Schoenfeld, M A; Heinze, H-J; Noesselt, T

2013-10-01

Although multisensory integration has been an important area of recent research, most studies focused on audiovisual integration. Importantly, however, the combination of audition and touch can guide our behavior as effectively which we studied here using psychophysics and functional magnetic resonance imaging (fMRI). We tested whether task-irrelevant tactile stimuli would enhance auditory detection, and whether hemispheric asymmetries would modulate these audiotactile benefits using lateralized sounds. Spatially aligned task-irrelevant tactile stimuli could occur either synchronously or asynchronously with the sounds. Auditory detection was enhanced by non-informative synchronous and asynchronous tactile stimuli, if presented on the left side. Elevated fMRI-signals to left-sided synchronous bimodal stimulation were found in primary auditory cortex (A1). Adjacent regions (planum temporale, PT) expressed enhanced BOLD-responses for synchronous and asynchronous left-sided bimodal conditions. Additional connectivity analyses seeded in right-hemispheric A1 and PT for both bimodal conditions showed enhanced connectivity with right-hemispheric thalamic, somatosensory and multisensory areas that scaled with subjects' performance. Our results indicate that functional asymmetries interact with audiotactile interplay which can be observed for left-lateralized stimulation in the right hemisphere. There, audiotactile interplay recruits a functional network of unisensory cortices, and the strength of these functional network connections is directly related to subjects' perceptual sensitivity. Copyright © 2013 Elsevier Inc. All rights reserved.

New Magnetic Microactuator Design Based on PDMS Elastomer and MEMS Technologies for Tactile Display.

PubMed

Streque, Jeremy; Talbi, Abdelkrim; Pernod, Philippe; Preobrazhensky, Vladimir

2010-01-01

Highly efficient tactile display devices must fulfill technical requirements for tactile stimulation, all the while preserving the lightness and compactness needed for handheld operation. This paper focuses on the elaboration of highly integrated magnetic microactuators for tactile display devices. FEM simulation, conception, fabrication, and characterization of these microactuators are presented in this paper. The current demonstrator offers a 4 × 4 flexible microactuator array with a resolution of 2 mm. Each actuator is composed of a Poly (Dimethyl-Siloxane) (PDMS) elastomeric membrane, magnetically actuated by coil-magnet interaction. It represents a proof of concept for fully integrated MEMS tactile devices, with fair actuation forces provided for a power consumption up to 100 mW per microactuator. The prototypes are destined to provide both static and dynamic tactile sensations, with an optimized membrane geometry for actuation frequencies between DC and 350 Hz. On the basis of preliminary experiments, this display device can offer skin stimulations for various tactile stimuli for applications in the fields of Virtual Reality or Human-Computer Interaction (HCI). Moreover, the elastomeric material used in this device and its global compactness offer great advantages in matter of comfort of use and capabilities of integration in haptic devices.

The display of tactile information

NASA Technical Reports Server (NTRS)

Sherrick, Carl E.

1991-01-01

There are a number of examples of natural tactile displays that can five us some insights about the solid geometry of touch, and recent experimental work on the subject has extended our thinking considerably. The concern of here is, however, more with synthetic or artificial displays for the production of a virtual environment. Features of synthetic displays that have enjoyed some success in one of the following two enterprises are discussed: the study of the spatio-temporal dimensions of stimuli that afford accurate and rapid processing of environmental information, or the use of displays in the design of sensory aids for disabled persons.

A Pneumatic Tactile Sensor for Co-Operative Robots

PubMed Central

He, Rui; Yu, Jianjun; Zuo, Guoyu

2017-01-01

Tactile sensors of comprehensive functions are urgently needed for the advanced robot to co-exist and co-operate with human beings. Pneumatic tactile sensors based on air bladder possess some noticeable advantages for human-robot interaction application. In this paper, we construct a pneumatic tactile sensor and apply it on the fingertip of robot hand to realize the sensing of force, vibration and slippage via the change of the pressure of the air bladder, and we utilize the sensor to perceive the object’s features such as softness and roughness. The pneumatic tactile sensor has good linearity, repeatability and low hysteresis and both its size and sensing range can be customized by using different material as well as different thicknesses of the air bladder. It is also simple and cheap to fabricate. Therefore, the pneumatic tactile sensor is suitable for the application of co-operative robots and can be widely utilized to improve the performance of service robots. We can apply it to the fingertip of the robot to endow the robotic hand with the ability to co-operate with humans and handle the fragile objects because of the inherent compliance of the air bladder. PMID:29125565

Tactile agnosia. Underlying impairment and implications for normal tactile object recognition.

PubMed

Reed, C L; Caselli, R J; Farah, M J

1996-06-01

In a series of experimental investigations of a subject with a unilateral impairment of tactile object recognition without impaired tactile sensation, several issues were addressed. First, is tactile agnosia secondary to a general impairment of spatial cognition? On tests of spatial ability, including those directed at the same spatial integration process assumed to be taxed by tactile object recognition, the subject performed well, implying a more specific impairment of high level, modality specific tactile perception. Secondly, within the realm of high level tactile perception, is there a distinction between the ability to derive shape ('what') and spatial ('where') information? Our testing showed an impairment confined to shape perception. Thirdly, what aspects of shape perception are impaired in tactile agnosia? Our results indicate that despite accurate encoding of metric length and normal manual exploration strategies, the ability tactually to perceive objects with the impaired hand, deteriorated as the complexity of shape increased. In addition, asymmetrical performance was not found for other body surfaces (e.g. her feet). Our results suggest that tactile shape perception can be disrupted independent of general spatial ability, tactile spatial ability, manual shape exploration, or even the precise perception of metric length in the tactile modality.

Feeling small: exploring the tactile perception limits.

PubMed

Skedung, Lisa; Arvidsson, Martin; Chung, Jun Young; Stafford, Christopher M; Berglund, Birgitta; Rutland, Mark W

2013-01-01

The human finger is exquisitely sensitive in perceiving different materials, but the question remains as to what length scales are capable of being distinguished in active touch. We combine material science with psychophysics to manufacture and haptically explore a series of topographically patterned surfaces of controlled wavelength, but identical chemistry. Strain-induced surface wrinkling and subsequent templating produced 16 surfaces with wrinkle wavelengths ranging from 300 nm to 90 μm and amplitudes between 7 nm and 4.5 μm. Perceived similarities of these surfaces (and two blanks) were pairwise scaled by participants, and interdistances among all stimuli were determined by individual differences scaling (INDSCAL). The tactile space thus generated and its two perceptual dimensions were directly linked to surface physical properties - the finger friction coefficient and the wrinkle wavelength. Finally, the lowest amplitude of the wrinkles so distinguished was approximately 10 nm, demonstrating that human tactile discrimination extends to the nanoscale.

Bilateral Symmetry of Distortions of Tactile Size Perception.

PubMed

Longo, Matthew R; Ghosh, Arko; Yahya, Tasneem

2015-01-01

The perceived distance between touches on the limbs is generally bigger for distances oriented across the width of the limb than for distances oriented along the length of the limb. The present study aimed to investigate the coherence of such distortions of tactile size perception across different skin surfaces. We investigated distortions of tactile size perception on the dorsal and palmar surfaces of both the left and right hands as well as the forehead. Participants judged which of two tactile distances felt larger. One distance was aligned with the proximodistal axis (along the body), the other with the mediolateral axis (across the body). Clear distortions were found on all five skin surfaces, with stimuli oriented across the width of the body being perceived as farther apart than those oriented along the length of the body. Consistent with previous results, distortions were smaller on the palmar than on the dorsal hand surface. Distortion on the forehead was intermediate between the dorsal and palmar surfaces. There were clear correlations between distortion on the left and right hands, for both the dorsal and palmar skin surfaces. In contrast, within each hand, there was no significant correlation between the two skin surfaces. Distortion on the forehead was not significantly correlated with that on any of the other skin surfaces. These results provide evidence for bilaterally symmetric representations underlying tactile size perception. © The Author(s) 2015.

Rapid temporal recalibration is unique to audiovisual stimuli.

PubMed

Van der Burg, Erik; Orchard-Mills, Emily; Alais, David

2015-01-01

Following prolonged exposure to asynchronous multisensory signals, the brain adapts to reduce the perceived asynchrony. Here, in three separate experiments, participants performed a synchrony judgment task on audiovisual, audiotactile or visuotactile stimuli and we used inter-trial analyses to examine whether temporal recalibration occurs rapidly on the basis of a single asynchronous trial. Even though all combinations used the same subjects, task and design, temporal recalibration occurred for audiovisual stimuli (i.e., the point of subjective simultaneity depended on the preceding trial's modality order), but none occurred when the same auditory or visual event was combined with a tactile event. Contrary to findings from prolonged adaptation studies showing recalibration for all three combinations, we show that rapid, inter-trial recalibration is unique to audiovisual stimuli. We conclude that recalibration occurs at two different timescales for audiovisual stimuli (fast and slow), but only on a slow timescale for audiotactile and visuotactile stimuli.

Reach Trajectories Characterize Tactile Localization for Sensorimotor Decision Making.

PubMed

Brandes, Janina; Heed, Tobias

2015-10-07

by merging skin location and body posture. By investigating human hand reach trajectories toward tactile stimuli on the feet, we provide experimental evidence that this transformation process is quick and efficient, and that its output is integrated with the original skin location in a fashion consistent with bounded integrator decision-making frameworks. Copyright © 2015 the authors 0270-6474/15/3513648-11$15.00/0.

Multimodal Bio-Inspired Tactile Sensing Module for Surface Characterization †

PubMed Central

Alves de Oliveira, Thiago Eustaquio; Cretu, Ana-Maria; Petriu, Emil M.

2017-01-01

Robots are expected to recognize the properties of objects in order to handle them safely and efficiently in a variety of applications, such as health and elder care, manufacturing, or high-risk environments. This paper explores the issue of surface characterization by monitoring the signals acquired by a novel bio-inspired tactile probe in contact with ridged surfaces. The tactile module comprises a nine Degree of Freedom Microelectromechanical Magnetic, Angular Rate, and Gravity system (9-DOF MEMS MARG) and a deep MEMS pressure sensor embedded in a compliant structure that mimics the function and the organization of mechanoreceptors in human skin as well as the hardness of the human skin. When the modules tip slides over a surface, the MARG unit vibrates and the deep pressure sensor captures the overall normal force exerted. The module is evaluated in two experiments. The first experiment compares the frequency content of the data collected in two setups: one when the module is mounted over a linear motion carriage that slides four grating patterns at constant velocities; the second when the module is carried by a robotic finger in contact with the same grating patterns while performing a sliding motion, similar to the exploratory motion employed by humans to detect object roughness. As expected, in the linear setup, the magnitude spectrum of the sensors’ output shows that the module can detect the applied stimuli with frequencies ranging from 3.66 Hz to 11.54 Hz with an overall maximum error of ±0.1 Hz. The second experiment shows how localized features extracted from the data collected by the robotic finger setup over seven synthetic shapes can be used to classify them. The classification method consists on applying multiscale principal components analysis prior to the classification with a multilayer neural network. Achieved accuracies from 85.1% to 98.9% for the various sensor types demonstrate the usefulness of traditional MEMS as tactile sensors embedded

Novel Tactile Sensor Technology and Smart Tactile Sensing Systems: A Review

PubMed Central

Ge, Chang; Wang, Z. Jane; Cretu, Edmond; Li, Xiaoou

2017-01-01

During the last decades, smart tactile sensing systems based on different sensing techniques have been developed due to their high potential in industry and biomedical engineering. However, smart tactile sensing technologies and systems are still in their infancy, as many technological and system issues remain unresolved and require strong interdisciplinary efforts to address them. This paper provides an overview of smart tactile sensing systems, with a focus on signal processing technologies used to interpret the measured information from tactile sensors and/or sensors for other sensory modalities. The tactile sensing transduction and principles, fabrication and structures are also discussed with their merits and demerits. Finally, the challenges that tactile sensing technology needs to overcome are highlighted. PMID:29149080

Hysteresis as an Implicit Prior in Tactile Spatial Decision Making

PubMed Central

Thiel, Sabrina D.; Bitzer, Sebastian; Nierhaus, Till; Kalberlah, Christian; Preusser, Sven; Neumann, Jane; Nikulin, Vadim V.; van der Meer, Elke; Villringer, Arno; Pleger, Burkhard

2014-01-01

Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide ‘same’ rather than ‘different’ on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants’ decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence. PMID:24587045

Mental rotation of tactile stimuli: using directional haptic cues in mobile devices.

PubMed

Gleeson, Brian T; Provancher, William R

2013-01-01

Haptic interfaces have the potential to enrich users' interactions with mobile devices and convey information without burdening the user's visual or auditory attention. Haptic stimuli with directional content, for example, navigational cues, may be difficult to use in handheld applications; the user's hand, where the cues are delivered, may not be aligned with the world, where the cues are to be interpreted. In such a case, the user would be required to mentally transform the stimuli between different reference frames. We examine the mental rotation of directional haptic stimuli in three experiments, investigating: 1) users' intuitive interpretation of rotated stimuli, 2) mental rotation of haptic stimuli about a single axis, and 3) rotation about multiple axes and the effects of specific hand poses and joint rotations. We conclude that directional haptic stimuli are suitable for use in mobile applications, although users do not naturally interpret rotated stimuli in any one universal way. We find evidence of cognitive processes involving the rotation of analog, spatial representations and discuss how our results fit into the larger body of mental rotation research. For small angles (e.g., less than 40 degree), these mental rotations come at little cost, but rotations with larger misalignment angles impact user performance. When considering the design of a handheld haptic device, our results indicate that hand pose must be carefully considered, as certain poses increase the difficulty of stimulus interpretation. Generally, all tested joint rotations impact task difficulty, but finger flexion and wrist rotation interact to greatly increase the cost of stimulus interpretation; such hand poses should be avoided when designing a haptic interface.

Vibrotactile pattern recognition: a portable compact tactile matrix.

PubMed

Thullier, Francine; Bolmont, Benoît; Lestienne, Francis G

2012-02-01

Compact tactile matrix (CTM) is a vibrotactile device composed of a seven-by-seven array of electromechanical vibrators "tactip" used to represent tactile patterns applied to a small skin area. The CTM uses a dynamic feature to generate spatiotemporal tactile patterns. The design requirements focus particularly on maximizing the transmission of the vibration from one tactip to the others as well as to the skin over a square area of 16 cm (2) while simultaneously minimizing the transmission of vibrations throughout the overall structure of the CTM. Experiments were conducted on 22 unpracticed subjects to evaluate how the CTM could be used to develop a tactile semantics for communication of instructions in order to test the ability of the subjects to identify: 1) directional prescriptors for gesture guidance and 2) instructional commands for operational task requirements in a military context. The results indicate that, after familiarization, recognition accuracies in the tactile patterns were remarkably precise for more 80% of the subjects. © 2011 IEEE

Natural Whisker-Guided Behavior by Head-Fixed Mice in Tactile Virtual Reality

PubMed Central

Sofroniew, Nicholas J.; Cohen, Jeremy D.; Lee, Albert K.

2014-01-01

During many natural behaviors the relevant sensory stimuli and motor outputs are difficult to quantify. Furthermore, the high dimensionality of the space of possible stimuli and movements compounds the problem of experimental control. Head fixation facilitates stimulus control and movement tracking, and can be combined with techniques for recording and manipulating neural activity. However, head-fixed mouse behaviors are typically trained through extensive instrumental conditioning. Here we present a whisker-based, tactile virtual reality system for head-fixed mice running on a spherical treadmill. Head-fixed mice displayed natural movements, including running and rhythmic whisking at 16 Hz. Whisking was centered on a set point that changed in concert with running so that more protracted whisking was correlated with faster running. During turning, whiskers moved in an asymmetric manner, with more retracted whisker positions in the turn direction and protracted whisker movements on the other side. Under some conditions, whisker movements were phase-coupled to strides. We simulated a virtual reality tactile corridor, consisting of two moveable walls controlled in a closed-loop by running speed and direction. Mice used their whiskers to track the walls of the winding corridor without training. Whisker curvature changes, which cause forces in the sensory follicles at the base of the whiskers, were tightly coupled to distance from the walls. Our behavioral system allows for precise control of sensorimotor variables during natural tactile navigation. PMID:25031397

Chills in Different Sensory Domains: Frisson Elicited by Acoustical, Visual, Tactile and Gustatory Stimuli

ERIC Educational Resources Information Center

Grewe, Oliver; Katzur, Bjorn; Kopiez, Reinhard; Altenmuller, Eckart

2011-01-01

"Chills" (frisson manifested as goose bumps or shivers) have been used in an increasing number of studies as indicators of emotions in response to music (e.g., Craig, 2005; Guhn, Hamm, & Zentner, 2007; McCrae, 2007; Panksepp, 1995; Sloboda, 1991). In this study we present evidence that chills can be induced through aural, visual, tactile, and…

Tactile cueing effects on performance in simulated aerial combat with high acceleration.

PubMed

van Erp, Jan B F; Eriksson, Lars; Levin, Britta; Carlander, Otto; Veltman, J A; Vos, Wouter K

2007-12-01

Recent evidence indicates that vibrotactile displays can potentially reduce the risk of sensory and cognitive overload. Before these displays can be introduced in super agile aircraft, it must be ascertained that vibratory stimuli can be sensed and interpreted by pilots subjected to high G loads. Each of 9 pilots intercepted 32 targets in the Swedish Dynamic Flight Simulator. Targets were indicated on simulated standard Gripen visual displays. In addition, in half of the trials target direction was also displayed on a 60-element tactile torso display. Performance measures and subjective ratings were recorded. Each pilot pulled G peaks above +8 Gz. With tactile cueing present, mean reaction time was reduced from 1458 ms (SE = 54) to 1245 ms (SE = 88). Mean total chase time for targets that popped up behind the pilot's aircraft was reduced from 13 s (SE = 0.45) to 12 s (SE = 0.41). Pilots rated the tactile display favorably over the visual displays at target pop-up on the easiness of detecting a threat presence and on the clarity of initial position of the threats. This study is the first to show that tactile display information is perceivable and useful in hypergravity (up to +9 Gz). The results show that the tactile display can capture attention at threat pop-up and improve threat awareness for threats in the back, even in the presence of high-end visual displays. It is expected that the added value of tactile displays may further increase after formal training and in situations of unexpected target pop-up.

Scalable, MEMS-enabled, vibrational tactile actuators for high resolution tactile displays

NASA Astrophysics Data System (ADS)

Xie, Xin; Zaitsev, Yuri; Velásquez-García, Luis Fernando; Teller, Seth J.; Livermore, Carol

2014-12-01

The design, fabrication, and characterization of a new type of tactile display for people with blindness or low vision is reported. Each tactile element comprises a piezoelectric extensional actuator that vibrates in plane, with a microfabricated scissor mechanism to convert the in-plane actuations into robust, higher-amplitude, out-of-plane (vertical) vibrations that are sensed with the finger pads. When the tactile elements are formed into a 2D array, information can be conveyed to the user by varying the pattern of vibrations in space and time. Analytical models and finite element analysis were used to design individual tactile elements, which were implemented with PZT actuators and both SU-8 and 3D-printed scissor amplifiers. The measured displacements of these 3 mm × 10 mm, MEMS-enabled tactile elements exceed 10 µm, in agreement with models, with measured forces exceeding 45 mN. The performance of the MEMS-enabled tactile elements is compared with the performance of larger, fully-macroscale tactile elements to demonstrate the scale dependence of the devices. The creation of a 28-element prototype is also reported, and the qualitative user experience with the individual tactile elements and displays is described.

Tactile event-related potentials in amyotrophic lateral sclerosis (ALS): Implications for brain-computer interface.

PubMed

Silvoni, S; Konicar, L; Prats-Sedano, M A; Garcia-Cossio, E; Genna, C; Volpato, C; Cavinato, M; Paggiaro, A; Veser, S; De Massari, D; Birbaumer, N

2016-01-01

We investigated neurophysiological brain responses elicited by a tactile event-related potential paradigm in a sample of ALS patients. Underlying cognitive processes and neurophysiological signatures for brain-computer interface (BCI) are addressed. We stimulated the palm of the hand in a group of fourteen ALS patients and a control group of ten healthy participants and recorded electroencephalographic signals in eyes-closed condition. Target and non-target brain responses were analyzed and classified offline. Classification errors served as the basis for neurophysiological brain response sub-grouping. A combined behavioral and quantitative neurophysiological analysis of sub-grouped data showed neither significant between-group differences, nor significant correlations between classification performance and the ALS patients' clinical state. Taking sequential effects of stimuli presentation into account, analyses revealed mean classification errors of 19.4% and 24.3% in healthy participants and ALS patients respectively. Neurophysiological correlates of tactile stimuli presentation are not altered by ALS. Tactile event-related potentials can be used to monitor attention level and task performance in ALS and may constitute a viable basis for future BCIs. Implications for brain-computer interface implementation of the proposed method for patients in critical conditions, such as the late stage of ALS and the (completely) locked-in state, are discussed. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

What colour does that feel? Tactile--visual mapping and the development of cross-modality.

PubMed

Ludwig, Vera U; Simner, Julia

2013-04-01

Humans share implicit preferences for cross-modal mappings (e.g., low pitch sounds are preferentially paired with darker colours). Individuals with synaesthesia experience cross-modal mappings to a conscious degree (e.g., they may see colours when they hear sounds). The neonatal synaesthesia hypothesis claims that all humans may be born with this explicit cross-modal perception, which dies out in most people through childhood, leaving only implicit associations in the average adult. Although there is evidence for decreasing cross-modality throughout early infancy, it is unclear whether this decline continues to take place throughout childhood and adolescence. This large-scale study had two goals. First, we aimed to establish whether human non-synaesthetes systematically map tactile and visual dimensions - a combination that has rarely been studied. Second, we asked whether tactile-visual associations may be more pronounced in younger compared to older participants. 210 participants between the ages of 5-74 years assigned colours to tactile stimuli. Smoothness, softness and roundness of stimuli positively correlated with luminance of the chosen colour; and smoothness and softness also positively correlated with chroma. Moreover, tactile sensations were associated with specific colours (e.g., softness with pink). There were no age differences for luminance effects. Chroma effects, however, were found exclusively in children and adolescents. Our findings are consistent with the neonatal synaesthesia hypothesis which suggests that all humans are born with strong cross-modal perception which is pruned away or inhibited throughout development. Moreover, the findings suggest that a decline of some forms of cross-modality may take place over a much longer time span than previously assumed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Retinotopically specific reorganization of visual cortex for tactile pattern recognition

PubMed Central

Cheung, Sing-Hang; Fang, Fang; He, Sheng; Legge, Gordon E.

2009-01-01

Although previous studies have shown that Braille reading and other tactile-discrimination tasks activate the visual cortex of blind and sighted people [1–5], it is not known whether this kind of cross-modal reorganization is influenced by retinotopic organization. We have addressed this question by studying S, a visually impaired adult with the rare ability to read print visually and Braille by touch. S had normal visual development until age six years, and thereafter severe acuity reduction due to corneal opacification, but no evidence of visual-field loss. Functional magnetic resonance imaging (fMRI) revealed that, in S’s early visual areas, tactile information processing activated what would be the foveal representation for normally-sighted individuals, and visual information processing activated what would be the peripheral representation. Control experiments showed that this activation pattern was not due to visual imagery. S’s high-level visual areas which correspond to shape- and object-selective areas in normally-sighted individuals were activated by both visual and tactile stimuli. The retinotopically specific reorganization in early visual areas suggests an efficient redistribution of neural resources in the visual cortex. PMID:19361999

Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans.

PubMed

Popescu, Elena Anda; Barlow, Steven M; Venkatesan, Lalit; Wang, Jingyan; Popescu, Mihai

2013-06-01

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography (MEG), we examined the patterns of short-term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the hand. Cutaneous stimuli were delivered as trains of serial pulses with a constant frequency of 2 Hz and 4 Hz in separate runs, and a constant inter-train interval of 5 s. The unilateral stimuli elicited transient responses to the serial pulses in the train, with several response components that were separated by independent component analysis. Subsequent source reconstruction techniques identified regional generators in the contralateral SI and somatosensory association areas in the posterior parietal cortex (PPC). Activity in the bilateral secondary somatosensory cortex (i.e., SII/PV) was also identified, although less consistently across subjects. The dynamics of the evoked activity in each area and the frequency-dependent adaptation effects were assessed from the changes in the relative amplitude of serial responses in each train. We show that the adaptation profiles in SI and PPC areas can be quantitatively characterized from neuromagnetic recordings using tactile stimulation, with the sensitivity to repetitive stimulation increasing from SI to PPC. A similar approach for SII/PV has proven less straightforward, potentially due to the tendency of these areas to respond selectively to certain stimuli. Copyright © 2011 Wiley Periodicals, Inc.

Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans

PubMed Central

Popescu, Anda; Barlow, Steven; Venkatesan, Lalit; Wang, Jingyan; Popescu, Mihai

2014-01-01

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography, we examined the patterns of short-term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the right hand. Cutaneous stimuli were delivered as trains of serial pulses with a constant frequency of 2 Hz and 4 Hz in separate runs, and a constant inter-train interval of 5 s. The unilateral stimuli elicited transient responses to the serial pulses in the train, with several response components that were separated by Independent Component Analysis. Subsequent neuromagnetic source reconstruction identified regional generators in the contralateral SI and somatosensory association areas in the posterior parietal cortex (PPC). Activity in the bilateral secondary somatosensory cortex (i.e. SII/PV) was also identified, although less consistently across subjects. The dynamics of the evoked activity in each area and the frequency-dependent adaptation effects were assessed from the changes in the relative amplitude of serial responses in each train. We show that the adaptation profiles in SI and PPC can be quantitatively characterized from neuromagnetic recordings using tactile stimulation, with the sensitivity to repetitive stimulation increasing from SI to PPC. A similar approach for SII/PV has proven less straightforward, potentially due to the selective nature of these areas to respond predominantly to certain stimuli. PMID:22331631

Sulfasalazine Blocks the Development of Tactile Allodynia in Diabetic Rats

PubMed Central

Berti-Mattera, Liliana N.; Kern, Timothy S.; Siegel, Ruth E.; Nemet, Ina; Mitchell, Rochanda

2008-01-01

OBJECTIVE—Diabetic neuropathy is manifested either by loss of nociception (painless syndrome) or by mechanical hyperalgesia and tactile allodynia (pain in response to nonpainful stimuli). While therapies with vasodilators or neurotrophins reverse some functional and metabolic abnormalities in diabetic nerves, they only partially ameliorate neuropathic pain. The reported link between nociception and targets of the anti-inflammatory drug sulfasalazine prompted us to investigate its effect on neuropathic pain in diabetes. RESEARCH DESIGN AND METHODS—We examined the effects of sulfasalazine, salicylates, and the poly(ADP-ribose) polymerase-1 inhibitor PJ34 on altered nociception in streptozotocin-induced diabetic rats. We also evaluated the levels of sulfasalazine targets in sciatic nerves and dorsal root ganglia (DRG) of treated animals. Finally, we analyzed the development of tactile allodynia in diabetic mice lacking expression of the sulfasalazine target nuclear factor-κB (NF-κB) p50. RESULTS—Sulfasalazine completely blocked the development of tactile allodynia in diabetic rats, whereas relatively minor effects were observed with other salicylates and PJ34. Along with the behavioral findings, sciatic nerves and DRG from sulfasalazine-treated diabetic rats displayed a decrease in NF-κB p50 expression compared with untreated diabetic animals. Importantly, the absence of tactile allodynia in diabetic NF-κB p50−/− mice supported a role for NF-κB in diabetic neuropathy. Sulfasalazine treatment also increased inosine levels in sciatic nerves of diabetic rats. CONCLUSIONS—The complete inhibition of tactile allodynia in experimental diabetes by sulfasalazine may stem from its ability to regulate both NF-κB and inosine. Sulfasalazine might be useful in the treatment of nociceptive alterations in diabetic patients. PMID:18633115

Tactile feedback to the palm using arbitrarily shaped DEA

NASA Astrophysics Data System (ADS)

Mößinger, Holger; Haus, Henry; Kauer, Michaela; Schlaak, Helmut F.

2014-03-01

Tactile stimulation enhances user experience and efficiency in human machine interaction by providing information via another sensory channel to the human brain. DEA as tactile interfaces have been in the focus of research in recent years. Examples are (vibro-) tactile keyboards or Braille displays. These applications of DEA focus mainly on interfacing with the user's fingers or fingertips only - demonstrating the high spatial resolution achievable with DEA. Besides providing a high resolution, the flexibility of DEA also allows designing free form surfaces equipped with single actuators or actuator matrices which can be fitted to the surface of the human skin. The actuators can then be used to provide tactile stimuli to different areas of the body, not to the fingertips only. Utilizing and demonstrating this flexibility we designed a free form DEA pad shaped to fit into the inside of the human palm. This pad consists of four single actuators which can provide e.g. directional information such as left, right, up and down. To demonstrate the value of such free form actuators we manufactured a PC-mouse using 3d printing processes. The actuator pad is mounted on the back of the mouse, resting against the palm while operating it. Software on the PC allows control of the vibration patterns displayed by the actuators. This allows helping the user by raising attention to certain directions or by discriminating between different modes like "pick" or "manipulate". Results of first tests of the device show an improved user experience while operating the PC mouse.

Optical based tactile shear and normal load sensor

DOEpatents

Salisbury, Curt Michael

2015-06-09

Various technologies described herein pertain to a tactile sensor that senses normal load and/or shear load. The tactile sensor includes a first layer and an optically transparent layer bonded together. At least a portion of the first layer is made of optically reflective material. The optically transparent layer is made of resilient material (e.g., clear silicone rubber). The tactile sensor includes light emitter/light detector pair(s), which respectively detect either normal load or shear load. Light emitter(s) emit light that traverses through the optically transparent layer and reflects off optically reflective material of the first layer, and light detector(s) detect and measure intensity of reflected light. When a normal load is applied, the optically transparent layer compresses, causing a change in reflected light intensity. When shear load is applied, a boundary between optically reflective material and optically absorptive material is laterally displaced, causing a change in reflected light intensity.

Compliant Tactile Sensors

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo R.

2011-01-01

Tactile sensors are currently being designed to sense interactions with human hands or pen-like interfaces. They are generally embedded in screens, keyboards, mousepads, and pushbuttons. However, they are not well fitted to sense interactions with all kinds of objects. A novel sensor was originally designed to investigate robotics manipulation where not only the contact with an object needs to be detected, but also where the object needs to be held and manipulated. This tactile sensor has been designed with features that allow it to sense a large variety of objects in human environments. The sensor is capable of detecting forces coming from any direction. As a result, this sensor delivers a force vector with three components. In contrast to most of the tactile sensors that are flat, this one sticks out from the surface so that it is likely to come in contact with objects. The sensor conforms to the object with which it interacts. This augments the contact's surface, consequently reducing the stress applied to the object. This feature makes the sensor ideal for grabbing objects and other applications that require compliance with objects. The operational range of the sensor allows it to operate well with objects found in peoples' daily life. The fabrication of this sensor is simple and inexpensive because of its compact mechanical configuration and reduced electronics. These features are convenient for mass production of individual sensors as well as dense arrays. The biologically inspired tactile sensor is sensitive to both normal and lateral forces, providing better feedback to the host robot about the object to be grabbed. It has a high sensitivity, enabling its use in manipulation fingers, which typically have low mechanical impedance in order to be very compliant. The construction of the sensor is simple, using inexpensive technologies like silicon rubber molding and standard stock electronics.

Tactile friction of topical formulations.

PubMed

Skedung, L; Buraczewska-Norin, I; Dawood, N; Rutland, M W; Ringstad, L

2016-02-01

The tactile perception is essential for all types of topical formulations (cosmetic, pharmaceutical, medical device) and the possibility to predict the sensorial response by using instrumental methods instead of sensory testing would save time and cost at an early stage product development. Here, we report on an instrumental evaluation method using tactile friction measurements to estimate perceptual attributes of topical formulations. Friction was measured between an index finger and an artificial skin substrate after application of formulations using a force sensor. Both model formulations of liquid crystalline phase structures with significantly different tactile properties, as well as commercial pharmaceutical moisturizing creams being more tactile-similar, were investigated. Friction coefficients were calculated as the ratio of the friction force to the applied load. The structures of the model formulations and phase transitions as a result of water evaporation were identified using optical microscopy. The friction device could distinguish friction coefficients between the phase structures, as well as the commercial creams after spreading and absorption into the substrate. In addition, phase transitions resulting in alterations in the feel of the formulations could be detected. A correlation was established between skin hydration and friction coefficient, where hydrated skin gave rise to higher friction. Also a link between skin smoothening and finger friction was established for the commercial moisturizing creams, although further investigations are needed to analyse this and correlations with other sensorial attributes in more detail. The present investigation shows that tactile friction measurements have potential as an alternative or complement in the evaluation of perception of topical formulations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Teaching children with autism spectrum disorder to tact olfactory stimuli.

PubMed

Dass, Tina K; Kisamore, April N; Vladescu, Jason C; Reeve, Kenneth F; Reeve, Sharon A; Taylor-Santa, Catherine

2018-05-28

Research on tact acquisition by children with autism spectrum disorder (ASD) has often focused on teaching participants to tact visual stimuli. It is important to evaluate procedures for teaching tacts of nonvisual stimuli (e.g., olfactory, tactile). The purpose of the current study was to extend the literature on secondary target instruction and tact training by evaluating the effects of a discrete-trial instruction procedure involving (a) echoic prompts, a constant prompt delay, and error correction for primary targets; (b) inclusion of secondary target stimuli in the consequent portion of learning trials; and (c) multiple exemplar training on the acquisition of item tacts of olfactory stimuli, emergence of category tacts of olfactory stimuli, generalization of category tacts, and emergence of category matching, with three children diagnosed with ASD. Results showed that all participants learned the item and category tacts following teaching, participants demonstrated generalization across category tacts, and category matching emerged for all participants. © 2018 Society for the Experimental Analysis of Behavior.

Attention to sound improves auditory reliability in audio-tactile spatial optimal integration.

PubMed

Vercillo, Tiziana; Gori, Monica

2015-01-01

The role of attention on multisensory processing is still poorly understood. In particular, it is unclear whether directing attention toward a sensory cue dynamically reweights cue reliability during integration of multiple sensory signals. In this study, we investigated the impact of attention in combining audio-tactile signals in an optimal fashion. We used the Maximum Likelihood Estimation (MLE) model to predict audio-tactile spatial localization on the body surface. We developed a new audio-tactile device composed by several small units, each one consisting of a speaker and a tactile vibrator independently controllable by external software. We tested participants in an attentional and a non-attentional condition. In the attentional experiment, participants performed a dual task paradigm: they were required to evaluate the duration of a sound while performing an audio-tactile spatial task. Three unisensory or multisensory stimuli, conflictual or not conflictual sounds and vibrations arranged along the horizontal axis, were presented sequentially. In the primary task participants had to evaluate in a space bisection task the position of the second stimulus (the probe) with respect to the others (the standards). In the secondary task they had to report occasionally changes in duration of the second auditory stimulus. In the non-attentional task participants had only to perform the primary task (space bisection). Our results showed an enhanced auditory precision (and auditory weights) in the auditory attentional condition with respect to the control non-attentional condition. The results of this study support the idea that modality-specific attention modulates multisensory integration.

Now You Feel both: Galvanic Vestibular Stimulation Induces Lasting Improvements in the Rehabilitation of Chronic Tactile Extinction

PubMed Central

Schmidt, Lena; Utz, Kathrin S.; Depper, Lena; Adams, Michaela; Schaadt, Anna-Katharina; Reinhart, Stefan; Kerkhoff, Georg

2013-01-01

Tactile extinction is frequent, debilitating, and often persistent after brain damage. Currently, there is no treatment available for this disorder. In two previous case studies we showed an influence of galvanic vestibular stimulation (GVS) on tactile extinction. Here, we evaluated in further patients the immediate and lasting effects of GVS on tactile extinction. GVS is known to induce polarity-specific changes in cerebral excitability in the vestibular cortices and adjacent cortical areas. Tactile extinction was examined with the Quality Extinction Test (QET) where subjects have to discriminate six different tactile fabrics in bilateral, double simultaneous stimulations on their dorsum of hands with identical or different tactile fabrics. Twelve patients with stable left-sided tactile extinction after unilateral right-hemisphere lesions were divided into two groups. The GVS group (N = 6) performed the QET under six different experimental conditions (two Baselines, Sham-GVS, left-cathodal/right-anodal GVS, right-cathodal/left-anodal GVS, and a Follow-up test). The second group of patients with left-sided extinction (N = 6) performed the QET six times repetitively, but without receiving GVS (control group). Both right-cathodal/left-anodal as well as left-cathodal/right-anodal GVS (mean: 0.7 mA) improved tactile identification of identical and different stimuli in the experimental group. These results show a generic effect of GVS on tactile extinction, but not in a polarity-specific way. These observed effects persisted at follow-up. Sham-GVS had no significant effect on extinction. In the control group, no significant improvements were seen in the QET after the six measurements of the QET, thus ruling out test repetition effects. In conclusion, GVS improved bodily awareness permanently for the contralesional body side in patients with tactile extinction and thus offers a novel treatment option for these patients. PMID:23519604

Tactile perception in blind Braille readers: a psychophysical study of acuity and hyperacuity using gratings and dot patterns.

PubMed

Grant, A C; Thiagarajah, M C; Sathian, K

2000-02-01

It is not clear whether the blind are generally superior to the sighted on measures of tactile sensitivity or whether they excel only on certain tests owing to the specifics of their tactile experience. We compared the discrimination performance of blind Braille readers and age-matched sighted subjects on three tactile tasks using precisely specified stimuli. Initially, the blind significantly outperformed the sighted at a hyperacuity task using Braille-like dot patterns, although, with practice, both groups performed equally well. On two other tasks, hyperacute discrimination of gratings that differed in ridge width and spatial-acuity-dependent discrimination of grating orientation, the performance of the blind did not differ significantly from that of sighted subjects. These results probably reflect the specificity of perceptual learning due to Braille-reading experience.

An overview of tactile sensing

NASA Technical Reports Server (NTRS)

Agrawal, Rajeev; Jain, Ramesh

1986-01-01

Existing or proposed tactile sensors are reviewed. General considerations involved in tactile sensing and various performance criteria are discussed. Typical specifications to be expected from the sensors are also described. A representative set of present day tactile sensors is studied. Finally, some of the proposed recognition systems using tactile sensing are described.

Tactile Signing with One-Handed Perception

ERIC Educational Resources Information Center

Mesch, Johanna

2013-01-01

Tactile signing among persons with deaf-blindness is not homogenous; rather, like other forms of language, it exhibits variation, especially in turn taking. Early analyses of tactile Swedish Sign Language, tactile Norwegian Sign Language, and tactile French Sign Language focused on tactile communication with four hands, in which partially blind or…

Why Early Tactile Speech Aids May Have Failed: No Perceptual Integration of Tactile and Auditory Signals.

PubMed

Rizza, Aurora; Terekhov, Alexander V; Montone, Guglielmo; Olivetti-Belardinelli, Marta; O'Regan, J Kevin

2018-01-01

Tactile speech aids, though extensively studied in the 1980's and 1990's, never became a commercial success. A hypothesis to explain this failure might be that it is difficult to obtain true perceptual integration of a tactile signal with information from auditory speech: exploitation of tactile cues from a tactile aid might require cognitive effort and so prevent speech understanding at the high rates typical of everyday speech. To test this hypothesis, we attempted to create true perceptual integration of tactile with auditory information in what might be considered the simplest situation encountered by a hearing-impaired listener. We created an auditory continuum between the syllables /BA/ and /VA/, and trained participants to associate /BA/ to one tactile stimulus and /VA/ to another tactile stimulus. After training, we tested if auditory discrimination along the continuum between the two syllables could be biased by incongruent tactile stimulation. We found that such a bias occurred only when the tactile stimulus was above, but not when it was below its previously measured tactile discrimination threshold. Such a pattern is compatible with the idea that the effect is due to a cognitive or decisional strategy, rather than to truly perceptual integration. We therefore ran a further study (Experiment 2), where we created a tactile version of the McGurk effect. We extensively trained two Subjects over 6 days to associate four recorded auditory syllables with four corresponding apparent motion tactile patterns. In a subsequent test, we presented stimulation that was either congruent or incongruent with the learnt association, and asked Subjects to report the syllable they perceived. We found no analog to the McGurk effect, suggesting that the tactile stimulation was not being perceptually integrated with the auditory syllable. These findings strengthen our hypothesis according to which tactile aids failed because integration of tactile cues with auditory speech

Why Early Tactile Speech Aids May Have Failed: No Perceptual Integration of Tactile and Auditory Signals

PubMed Central

Rizza, Aurora; Terekhov, Alexander V.; Montone, Guglielmo; Olivetti-Belardinelli, Marta; O’Regan, J. Kevin

2018-01-01

Tactile speech aids, though extensively studied in the 1980’s and 1990’s, never became a commercial success. A hypothesis to explain this failure might be that it is difficult to obtain true perceptual integration of a tactile signal with information from auditory speech: exploitation of tactile cues from a tactile aid might require cognitive effort and so prevent speech understanding at the high rates typical of everyday speech. To test this hypothesis, we attempted to create true perceptual integration of tactile with auditory information in what might be considered the simplest situation encountered by a hearing-impaired listener. We created an auditory continuum between the syllables /BA/ and /VA/, and trained participants to associate /BA/ to one tactile stimulus and /VA/ to another tactile stimulus. After training, we tested if auditory discrimination along the continuum between the two syllables could be biased by incongruent tactile stimulation. We found that such a bias occurred only when the tactile stimulus was above, but not when it was below its previously measured tactile discrimination threshold. Such a pattern is compatible with the idea that the effect is due to a cognitive or decisional strategy, rather than to truly perceptual integration. We therefore ran a further study (Experiment 2), where we created a tactile version of the McGurk effect. We extensively trained two Subjects over 6 days to associate four recorded auditory syllables with four corresponding apparent motion tactile patterns. In a subsequent test, we presented stimulation that was either congruent or incongruent with the learnt association, and asked Subjects to report the syllable they perceived. We found no analog to the McGurk effect, suggesting that the tactile stimulation was not being perceptually integrated with the auditory syllable. These findings strengthen our hypothesis according to which tactile aids failed because integration of tactile cues with auditory speech

Somatosensory map expansion and altered processing of tactile inputs in a mouse model of fragile X syndrome.

PubMed

Juczewski, Konrad; von Richthofen, Helen; Bagni, Claudia; Celikel, Tansu; Fisone, Gilberto; Krieger, Patrik

2016-12-01

Fragile X syndrome (FXS) is a common inherited form of intellectual disability caused by the absence or reduction of the fragile X mental retardation protein (FMRP) encoded by the FMR1 gene. In humans, one symptom of FXS is hypersensitivity to sensory stimuli, including touch. We used a mouse model of FXS (Fmr1 KO) to study sensory processing of tactile information conveyed via the whisker system. In vivo electrophysiological recordings in somatosensory barrel cortex showed layer-specific broadening of the receptive fields at the level of layer 2/3 but not layer 4, in response to whisker stimulation. Furthermore, the encoding of tactile stimuli at different frequencies was severely affected in layer 2/3. The behavioral effect of this broadening of the receptive fields was tested in the gap-crossing task, a whisker-dependent behavioral paradigm. In this task the Fmr1 KO mice showed differences in the number of whisker contacts with platforms, decrease in the whisker sampling duration and reduction in the whisker touch-time while performing the task. We propose that the increased excitability in the somatosensory barrel cortex upon whisker stimulation may contribute to changes in the whisking strategy as well as to other observed behavioral phenotypes related to tactile processing in Fmr1 KO mice. Copyright © 2016 Elsevier Inc. All rights reserved.

C-tactile afferent stimulating touch carries a positive affective value.

PubMed

Pawling, Ralph; Cannon, Peter R; McGlone, Francis P; Walker, Susannah C

2017-01-01

The rewarding sensation of touch in affiliative interactions is hypothesized to be underpinned by a specialized system of nerve fibers called C-Tactile afferents (CTs), which respond optimally to slowly moving, gentle touch, typical of a caress. However, empirical evidence to support the theory that CTs encode socially relevant, rewarding tactile information in humans is currently limited. While in healthy participants, touch applied at CT optimal velocities (1-10cm/sec) is reliably rated as subjectively pleasant, neuronopathy patients lacking large myelinated afferents, but with intact C-fibres, report that the conscious sensation elicited by stimulation of CTs is rather vague. Given this weak perceptual impact the value of self-report measures for assessing the specific affective value of CT activating touch appears limited. Therefore, we combined subjective ratings of touch pleasantness with implicit measures of affective state (facial electromyography) and autonomic arousal (heart rate) to determine whether CT activation carries a positive affective value. We recorded the activity of two key emotion-relevant facial muscle sites (zygomaticus major-smile muscle, positive affect & corrugator supercilii-frown muscle, negative affect) while participants evaluated the pleasantness of experimenter administered stroking touch, delivered using a soft brush, at two velocities (CT optimal 3cm/sec & CT non-optimal 30cm/sec), on two skin sites (CT innervated forearm & non-CT innervated palm). On both sites, 3cm/sec stroking touch was rated as more pleasant and produced greater heart rate deceleration than 30cm/sec stimulation. However, neither self-report ratings nor heart rate responses discriminated stimulation on the CT innervated arm from stroking of the non-CT innervated palm. In contrast, significantly greater activation of the zygomaticus major (smiling muscle) was seen specifically to CT optimal, 3cm/sec, stroking on the forearm in comparison to all other stimuli

Tactile Evaluation Feedback System for Multi-Layered Structure Inspired by Human Tactile Perception Mechanism.

PubMed

Hashim, Iza Husna Mohamad; Kumamoto, Shogo; Takemura, Kenjiro; Maeno, Takashi; Okuda, Shin; Mori, Yukio

2017-11-11

Tactile sensation is one type of valuable feedback in evaluating a product. Conventionally, sensory evaluation is used to get direct subjective responses from the consumers, in order to improve the product's quality. However, this method is a time-consuming and costly process. Therefore, this paper proposes a novel tactile evaluation system that can give tactile feedback from a sensor's output. The main concept of this system is hierarchically layering the tactile sensation, which is inspired by the flow of human perception. The tactile sensation is classified from low-order of tactile sensation (LTS) to high-order of tactile sensation (HTS), and also to preference. Here, LTS will be correlated with physical measures. Furthermore, the physical measures that are used to correlate with LTS are selected based on four main aspects of haptic information (roughness, compliance, coldness, and slipperiness), which are perceived through human tactile sensors. By using statistical analysis, the correlation between each hierarchy was obtained, and the preference was derived in terms of physical measures. A verification test was conducted by using unknown samples to determine the reliability of the system. The results showed that the system developed was capable of estimating preference with an accuracy of approximately 80%.

Availability of vision and tactile gating: vision enhances tactile sensitivity.

PubMed

Colino, Francisco L; Lee, Ji-Hang; Binsted, Gordon

2017-01-01

A multitude of events bombard our sensory systems at every moment of our lives. Thus, it is important for the sensory and motor cortices to gate unimportant events. Tactile suppression is a well-known phenomenon defined as a reduced ability to detect tactile events on the skin before and during movement. Previous experiments (Buckingham et al. in Exp Brain Res 201(3):411-419, 2010; Colino et al. in Physiol Rep 2(3):e00267, 2014) found detection rates decrease just prior to and during finger abduction and decrease according to the proximity of the moving effector. However, what effect does vision have on tactile gating? There is ample evidence (see Serino and Haggard in Neurosci Biobehav Rev 34:224-236, 2010) observing increased tactile acuity when participants see their limbs. The present study examined how tactile detection changes in response to visual condition (vision/no vision). Ten human participants used their right hand to reach and grasp a cylinder. Tactors were attached to the index finger and the forearm of both the right and left arm and vibrated at various epochs relative to a "go" tone. Results replicate previous findings from our laboratory (Colino et al. in Physiol Rep 2(3):e00267, 2014). Also, tactile acuity decreased when participants did not have vision. These results indicate that the vision affects the somatosensation via inputs from parietal areas (Konen and Haggard in Cereb Cortex 24(2):501-507, 2014) but does so in a reach-to-grasp context.

Microstructured graphene arrays for highly sensitive flexible tactile sensors.

PubMed

Zhu, Bowen; Niu, Zhiqiang; Wang, Hong; Leow, Wan Ru; Wang, Hua; Li, Yuangang; Zheng, Liyan; Wei, Jun; Huo, Fengwei; Chen, Xiaodong

2014-09-24

A highly sensitive tactile sensor is devised by applying microstructured graphene arrays as sensitive layers. The combination of graphene and anisotropic microstructures endows this sensor with an ultra-high sensitivity of -5.53 kPa(-1) , an ultra-fast response time of only 0.2 ms, as well as good reliability, rendering it promising for the application of tactile sensing in artificial skin and human-machine interface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hierarchical equivalence of somatosensory areas I and II for tactile processing in the cerebral cortex of the marmoset monkey.

PubMed

Zhang, H Q; Zachariah, M K; Coleman, G T; Rowe, M J

2001-05-01

Responsiveness of the first somatosensory area (SI) of the cerebral cortex was investigated in the marmoset monkey (Callithrix jacchus) in association with cooling-induced, reversible inactivation of the second somatosensory area, SII. The aim was to determine whether SI responsiveness to peripheral tactile stimulation depends on SII and therefore whether SI and SII in the marmoset occupy hierarchically equivalent positions in a parallel organizational scheme for thalamocortical tactile processing as appears to be the case in nonprimate mammals. Inactivation of SII was achieved when the temperature over SII was lowered to < or =12 degrees C, as indicated by abolition of the SII-evoked potentials generated by brief tap stimuli to the hand or foot, and by abolition of tactile responses in single SII neurons located at the margin beneath the block. The effect of SII inactivation on SI-evoked potentials was examined in 16 experiments by simultaneous recording of the SI- and SII-evoked potentials. SI-evoked potentials were never abolished and remained unaffected in 11 cases. In three experiments there was a small reduction in amplitude and inconsistent effects in the remaining two. Responsiveness to controlled tactile stimuli was examined quantitatively in 31 individual SI neurons of different functional classes before, during, and after the inactivation of SII. Tactile responsiveness in individual SI neurons was never abolished by SII inactivation, remaining unchanged in 20 neurons (65%) while undergoing some reduction in the remaining 11 SI neurons (35%). This reduction of tactile responsiveness in one-third of SI neurons is most likely attributable to a removal of a facilitatory influence emanating from SII, based on the observation that background activity of the affected neurons was also reduced. Furthermore, phase locking of SI responses to vibrotactile stimulation was unchanged when SII was inactivated. The retention of responsiveness in SI neurons when SII was

Pure associative tactile agnosia for the left hand: clinical and anatomo-functional correlations.

PubMed

Veronelli, Laura; Ginex, Valeria; Dinacci, Daria; Cappa, Stefano F; Corbo, Massimo

2014-09-01

Associative tactile agnosia (TA) is defined as the inability to associate information about object sensory properties derived through tactile modality with previously acquired knowledge about object identity. The impairment is often described after a lesion involving the parietal cortex (Caselli, 1997; Platz, 1996). We report the case of SA, a right-handed 61-year-old man affected by first ever right hemispheric hemorrhagic stroke. The neurological examination was normal, excluding major somaesthetic and motor impairment; a brain magnetic resonance imaging (MRI) confirmed the presence of a right subacute hemorrhagic lesion limited to the post-central and supra-marginal gyri. A comprehensive neuropsychological evaluation detected a selective inability to name objects when handled with the left hand in the absence of other cognitive deficits. A series of experiments were conducted in order to assess each stage of tactile recognition processing using the same stimulus sets: materials, 3D geometrical shapes, real objects and letters. SA and seven matched controls underwent the same experimental tasks during four sessions in consecutive days. Tactile discrimination, recognition, pantomime, drawing after haptic exploration out of vision and tactile-visual matching abilities were assessed. In addition, we looked for the presence of a supra-modal impairment of spatial perception and of specific difficulties in programming exploratory movements during recognition. Tactile discrimination was intact for all the stimuli tested. In contrast, SA was able neither to recognize nor to pantomime real objects manipulated with the left hand out of vision, while he identified them with the right hand without hesitations. Tactile-visual matching was intact. Furthermore, SA was able to grossly reproduce the global shape in drawings but failed to extract details of objects after left-hand manipulation, and he could not identify objects after looking at his own drawings. This case

Learning and recognition of tactile temporal sequences by mice and humans

PubMed Central

Bale, Michael R; Bitzidou, Malamati; Pitas, Anna; Brebner, Leonie S; Khazim, Lina; Anagnou, Stavros T; Stevenson, Caitlin D; Maravall, Miguel

2017-01-01

The world around us is replete with stimuli that unfold over time. When we hear an auditory stream like music or speech or scan a texture with our fingertip, physical features in the stimulus are concatenated in a particular order. This temporal patterning is critical to interpreting the stimulus. To explore the capacity of mice and humans to learn tactile sequences, we developed a task in which subjects had to recognise a continuous modulated noise sequence delivered to whiskers or fingertips, defined by its temporal patterning over hundreds of milliseconds. GO and NO-GO sequences differed only in that the order of their constituent noise modulation segments was temporally scrambled. Both mice and humans efficiently learned tactile sequences. Mouse sequence recognition depended on detecting transitions in noise amplitude; animals could base their decision on the earliest information available. Humans appeared to use additional cues, including the duration of noise modulation segments. DOI: http://dx.doi.org/10.7554/eLife.27333.001 PMID:28812976

Development of a tactile display with 5 mm resolution using an array of magnetorheological fluid

NASA Astrophysics Data System (ADS)

Ishizuka, Hiroki; Miki, Norihisa

2017-06-01

In this study, we demonstrate the design and evaluation of a stiffness tactile display using a magnetorheological (MR) fluid. The tactile display is based on the change in mechanical properties under an external magnetic field. In the tactile display, the MR fluid is encapsulated in chambers of 3 mm diameter and arranged at intervals of 2 mm. Magnetic fields were spatially applied to the tactile display using neodymium magnets of 3.5 mm diameter. The design and spatial magnetic field application enable the tactile display to present stiff dots of 5 mm resolution. We confirmed that the tactile display can present a spatial stiff dot and its pattern on the surface by compression experiments. Sensory evaluation revealed that the users were able to perceive the approximate position of the stiff dots. From the experiments, the tactile display has potential as a palpation tactile display and requires improvement to present various types of tissues.

Structural design and output characteristic analysis of magnetostrictive tactile sensor for robotic applications

NASA Astrophysics Data System (ADS)

Zheng, Wendong; Wang, Bowen; Liu, Huaping; Li, Yunkai; Zhao, Ran; Weng, Ling; Zhang, Changgeng

2018-05-01

A novel magnetostrictive tactile sensor has been designed according to the transduction mechanism of cilia and Villari effect of iron-gallium alloy. The tactile sensor consists of a Galfenol beam, a pair of permanent magnets, a Hall sensor and a signal processing system. Compared with the conventional tactile sensor, our proposed tactile sensor can not only detect the contact-force, but also sense stiffness of an object. The performance and measurement range of tactile sensor have theoretically been analyzed and experimentally investigated. The results have revealed that the sensibility of tactile sensor for sensing force is up to 22.81mV/N at applied bias magnetic field of 2.56kA/m. Moreover, the sensor can effectively discriminate objects with different stiffness. The sensor is characterized by high sensitivity, good linearity, and quick response. It has the potential of being miniaturized and integrated into the finger of a robotic hand to realize force sensing and object recognition in real-time.

Tactile device utilizing a single magnetorheological sponge: experimental investigation

NASA Astrophysics Data System (ADS)

Kim, Soomin; Kim, Pyunghwa; Choi, Seung-Hyun; Oh, Jong-Seok; Choi, Seung-Bok

2015-04-01

In the field of medicine, several new areas have been currently introduced such as robot-assisted surgery. However, the major drawback of these systems is that there is no tactile communication between doctors and surgical sites. When the tactile system is brought up, telemedicine including telerobotic surgery can be enhanced much more than now. In this study, a new tactile device is designed using a single magnetorhological (MR) sponge cell to realize the sensation of human organs. MR fluids and an open celled polyurethane foam are used to propose the MR sponge cell. The viscous and elastic sensational behaviors of human organs are realized by the MR sponge cell. Before developing the tactile device, tactile sensation according to touch of human fingers are quantified in advance. The finger is then treated as a reduced beam bundle model (BBM) in which the fingertip is comprised of an elastic beam virtually. Under the reduced BBM, when people want to sense an object, the fingertip is investigated by pushing and sliding. Accordingly, while several magnitudes of magnetic fields are applied to the tactile device, normal and tangential reaction forces and bending moment are measured by 6-axis force/torque sensor instead of the fingertip. These measured data are used to compare with soft tissues. It is demonstrated that the proposed MR sponge cell can realize any part of the organ based on the obtained data.

Tactile Radar: experimenting a computer game with visually disabled.

PubMed

Kastrup, Virgínia; Cassinelli, Alvaro; Quérette, Paulo; Bergstrom, Niklas; Sampaio, Eliana

2017-09-18

Visually disabled people increasingly use computers in everyday life, thanks to novel assistive technologies better tailored to their cognitive functioning. Like sighted people, many are interested in computer games - videogames and audio-games. Tactile-games are beginning to emerge. The Tactile Radar is a device through which a visually disabled person is able to detect distal obstacles. In this study, it is connected to a computer running a tactile-game. The game consists in finding and collecting randomly arranged coins in a virtual room. The study was conducted with nine congenital blind people including both sexes, aged 20-64 years old. Complementary methods of first and third person were used: the debriefing interview and the quasi-experimental design. The results indicate that the Tactile Radar is suitable for the creation of computer games specifically tailored for visually disabled people. Furthermore, the device seems capable of eliciting a powerful immersive experience. Methodologically speaking, this research contributes to the consolidation and development of first and third person complementary methods, particularly useful in disabled people research field, including the evaluation by users of the Tactile Radar effectiveness in a virtual reality context. Implications for rehabilitation Despite the growing interest in virtual games for visually disabled people, they still find barriers to access such games. Through the development of assistive technologies such as the Tactile Radar, applied in virtual games, we can create new opportunities for leisure, socialization and education for visually disabled people. The results of our study indicate that the Tactile Radar is adapted to the creation of video games for visually disabled people, providing a playful interaction with the players.

Texture- and deformability-based surface recognition by tactile image analysis.

PubMed

Khasnobish, Anwesha; Pal, Monalisa; Tibarewala, D N; Konar, Amit; Pal, Kunal

2016-08-01

Deformability and texture are two unique object characteristics which are essential for appropriate surface recognition by tactile exploration. Tactile sensation is required to be incorporated in artificial arms for rehabilitative and other human-computer interface applications to achieve efficient and human-like manoeuvring. To accomplish the same, surface recognition by tactile data analysis is one of the prerequisites. The aim of this work is to develop effective technique for identification of various surfaces based on deformability and texture by analysing tactile images which are obtained during dynamic exploration of the item by artificial arms whose gripper is fitted with tactile sensors. Tactile data have been acquired, while human beings as well as a robot hand fitted with tactile sensors explored the objects. The tactile images are pre-processed, and relevant features are extracted from the tactile images. These features are provided as input to the variants of support vector machine (SVM), linear discriminant analysis and k-nearest neighbour (kNN) for classification. Based on deformability, six household surfaces are recognized from their corresponding tactile images. Moreover, based on texture five surfaces of daily use are classified. The method adopted in the former two cases has also been applied for deformability- and texture-based recognition of four biomembranes, i.e. membranes prepared from biomaterials which can be used for various applications such as drug delivery and implants. Linear SVM performed best for recognizing surface deformability with an accuracy of 83 % in 82.60 ms, whereas kNN classifier recognizes surfaces of daily use having different textures with an accuracy of 89 % in 54.25 ms and SVM with radial basis function kernel recognizes biomembranes with an accuracy of 78 % in 53.35 ms. The classifiers are observed to generalize well on the unseen test datasets with very high performance to achieve efficient material

Tactile Imaging Markers to Characterize Female Pelvic Floor Conditions.

PubMed

van Raalte, Heather; Egorov, Vladimir

2015-08-01

The Vaginal Tactile Imager (VTI) records pressure patterns from vaginal walls under an applied tissue deformation and during pelvic floor muscle contractions. The objective of this study is to validate tactile imaging and muscle contraction parameters (markers) sensitive to the female pelvic floor conditions. Twenty-two women with normal and prolapse conditions were examined by a vaginal tactile imaging probe. We identified 9 parameters which were sensitive to prolapse conditions ( p < 0.05 for one-way ANOVA and/or p < 0.05 for t -test with correlation factor r from -0.73 to -0.56). The list of parameters includes pressure, pressure gradient and dynamic pressure response during muscle contraction at identified locations. These parameters may be used for biomechanical characterization of female pelvic floor conditions to support an effective management of pelvic floor prolapse.

Tactile perception and working memory in rats and humans

PubMed Central

Fassihi, Arash; Akrami, Athena; Esmaeili, Vahid; Diamond, Mathew E.

2014-01-01

Primates can store sensory stimulus parameters in working memory for subsequent manipulation, but until now, there has been no demonstration of this capacity in rodents. Here we report tactile working memory in rats. Each stimulus is a vibration, generated as a series of velocity values sampled from a normal distribution. To perform the task, the rat positions its whiskers to receive two such stimuli, “base” and “comparison,” separated by a variable delay. It then judges which stimulus had greater velocity SD. In analogous experiments, humans compare two vibratory stimuli on the fingertip. We demonstrate that the ability of rats to hold base stimulus information (for up to 8 s) and their acuity in assessing stimulus differences overlap the performance demonstrated by humans. This experiment highlights the ability of rats to perceive the statistical structure of vibrations and reveals their previously unknown capacity to store sensory information in working memory. PMID:24449850

Tactile Sensitivity in Asperger Syndrome

ERIC Educational Resources Information Center

Blakemore, Sarah-Jayne; Tavassoli, Teresa; Calo, Susana; Thomas, Richard M.; Catmur, Caroline; Frith, Uta; Haggard, Patrick

2006-01-01

People with autism and Asperger syndrome are anecdotally said to be hypersensitive to touch. In two experiments, we measured tactile thresholds and suprathreshold tactile sensitivity in a group of adults with Asperger syndrome. In the first experiment, tactile perceptual thresholds were measured. Two frequencies of vibrotactile stimulation were…

Dissociated active and passive tactile shape recognition: a case study of pure tactile apraxia.

PubMed

Valenza, N; Ptak, R; Zimine, I; Badan, M; Lazeyras, F; Schnider, A

2001-11-01

Disorders of tactile object recognition (TOR) may result from primary motor or sensory deficits or higher cognitive impairment of tactile shape representations or semantic memory. Studies with healthy participants suggest the existence of exploratory motor procedures directly linked to the extraction of specific properties of objects. A pure deficit of these procedures without concomitant gnostic disorders has never been described in a brain-damaged patient. Here, we present a patient with a right hemispheric infarction who, in spite of intact sensorimotor functions, had impaired TOR with the left hand. Recognition of 2D shapes and objects was severely deficient under the condition of spontaneous exploration. Tactile exploration of shapes was disorganized and exploratory procedures, such as the contour-following strategy, which is necessary to identify the precise shape of an object, were severely disturbed. However, recognition of 2D shapes under manually or verbally guided exploration and the recognition of shapes traced on the skin were intact, indicating a dissociation in shape recognition between active and passive touch. Functional MRI during sensory stimulation of the left hand showed preserved activation of the spared primary sensory cortex in the right hemisphere. We interpret the deficit of our patient as a pure tactile apraxia without tactile agnosia, i.e. a specific inability to use tactile feedback to generate the exploratory procedures necessary for tactile shape recognition.

Recent Progress in Technologies for Tactile Sensors

PubMed Central

Sun, Xuguang; Xue, Ning; Li, Tong; Liu, Chang

2018-01-01

Over the last two decades, considerable scientific and technological efforts have been devoted to developing tactile sensing based on a variety of transducing mechanisms, with prospective applications in many fields such as human–machine interaction, intelligent robot tactile control and feedback, and tactile sensorized minimally invasive surgery. This paper starts with an introduction of human tactile systems, followed by a presentation of the basic demands of tactile sensors. State-of-the-art tactile sensors are reviewed in terms of their diverse sensing mechanisms, design consideration, and material selection. Subsequently, typical performances of the sensors, along with their advantages and disadvantages, are compared and analyzed. Two major potential applications of tactile sensing systems are discussed in detail. Lastly, we propose prospective research directions and market trends of tactile sensing systems. PMID:29565835

Recent Progress in Technologies for Tactile Sensors.

PubMed

Chi, Cheng; Sun, Xuguang; Xue, Ning; Li, Tong; Liu, Chang

2018-03-22

Over the last two decades, considerable scientific and technological efforts have been devoted to developing tactile sensing based on a variety of transducing mechanisms, with prospective applications in many fields such as human-machine interaction, intelligent robot tactile control and feedback, and tactile sensorized minimally invasive surgery. This paper starts with an introduction of human tactile systems, followed by a presentation of the basic demands of tactile sensors. State-of-the-art tactile sensors are reviewed in terms of their diverse sensing mechanisms, design consideration, and material selection. Subsequently, typical performances of the sensors, along with their advantages and disadvantages, are compared and analyzed. Two major potential applications of tactile sensing systems are discussed in detail. Lastly, we propose prospective research directions and market trends of tactile sensing systems.

Sensory Responsiveness and the Effects of Equal Subjective Rewards on Tactile Learning and Memory of Honeybees

ERIC Educational Resources Information Center

Scheiner, Ricarda; Kuritz-Kaiser, Anthea; Menzel, Randolf; Erber, Joachim

2005-01-01

In tactile learning, sucrose is the unconditioned stimulus and reward, which is usually applied to the antenna to elicit proboscis extension and which the bee can drink when it is subsequently applied to the extended proboscis. The conditioned stimulus is a tactile object that the bee can scan with its antennae. In this paper we describe the…

From innervation density to tactile acuity: 1. Spatial representation.

PubMed

Brown, Paul B; Koerber, H Richard; Millecchia, Ronald

2004-06-11

We tested the hypothesis that the population receptive field representation (a superposition of the excitatory receptive field areas of cells responding to a tactile stimulus) provides spatial information sufficient to mediate one measure of static tactile acuity. In psychophysical tests, two-point discrimination thresholds on the hindlimbs of adult cats varied as a function of stimulus location and orientation, as they do in humans. A statistical model of the excitatory low threshold mechanoreceptive fields of spinocervical, postsynaptic dorsal column and spinothalamic tract neurons was used to simulate the population receptive field representations in this neural population of the one- and two-point stimuli used in the psychophysical experiments. The simulated and observed thresholds were highly correlated. Simulated and observed thresholds' relations to physiological and anatomical variables such as stimulus location and orientation, receptive field size and shape, map scale, and innervation density were strikingly similar. Simulated and observed threshold variations with receptive field size and map scale obeyed simple relationships predicted by the signal detection model, and were statistically indistinguishable from each other. The population receptive field representation therefore contains information sufficient for this discrimination.

Tactile Imaging Markers to Characterize Female Pelvic Floor Conditions

PubMed Central

van Raalte, Heather; Egorov, Vladimir

2015-01-01

The Vaginal Tactile Imager (VTI) records pressure patterns from vaginal walls under an applied tissue deformation and during pelvic floor muscle contractions. The objective of this study is to validate tactile imaging and muscle contraction parameters (markers) sensitive to the female pelvic floor conditions. Twenty-two women with normal and prolapse conditions were examined by a vaginal tactile imaging probe. We identified 9 parameters which were sensitive to prolapse conditions (p < 0.05 for one-way ANOVA and/or p < 0.05 for t-test with correlation factor r from −0.73 to −0.56). The list of parameters includes pressure, pressure gradient and dynamic pressure response during muscle contraction at identified locations. These parameters may be used for biomechanical characterization of female pelvic floor conditions to support an effective management of pelvic floor prolapse. PMID:26389014

Optical-to-Tactile Translator

NASA Technical Reports Server (NTRS)

Langevin, Maurice L. (Inventor); Moynihan, Philip I. (Inventor)

2000-01-01

An optical-to-tactile translator provides an aid for the visually impaired by translating a near-field scene to a tactile signal corresponding to said near-field scene. An optical sensor using a plurality of active pixel sensors (APS) converts the optical image within the near-field scene to a digital signal. The digital signal is then processed by a microprocessor and a simple shape signal is generated based on the digital signal. The shape signal is then communicated to a tactile transmitter where the shape signal is converted into a tactile signal using a series of contacts. The shape signal may be an outline of the significant shapes determined in the near-field scene, or the shape signal may comprise a simple symbolic representation of common items encountered repeatedly. The user is thus made aware of the unseen near-field scene, including potential obstacles and dangers, through a series of tactile contacts. In a preferred embodiment, a range determining device such as those commonly found on auto-focusing cameras is included to limit the distance that the optical sensor interprets the near-field scene.

Tactile communication using a CO(2) flux stimulation for blind or deafblind people.

PubMed

da Cunha, Jose Carlos; Bordignon, Luiz Alberto; Nohama, Percy

2010-01-01

This paper describes a tactile stimulation system for producing nonvisual image patterns to blind or deafblind people. The stimulator yields a CO(2) pulsatile flux directed to the user's skin throughout a needle that is coupled to a 2-D tactile plotter. The fluxtactile plotter operates with two step motor mounted on a wood structure, controlled by a program developed to produce alphanumerical characters and geometric figures of different size and speed, which will be used to investigate the psychophysical properties of this kind of tactile communication. CO(2) is provided by a cylinder that delivers a stable flux, which is converted to a pulsatile mode through a high frequency solenoid valve that can chop it up to 1 kHz. Also, system temperature is controlled by a Peltier based device. Tests on the prototype indicate that the system is a valuable tool to investigate the psychophysical properties of the skin in response to stimulation by CO(2) jet, allowing a quantitative and qualitative analysis as a function of stimulation parameters. With the system developed, it was possible to plot the geometric figures proposed: triangles, rectangles and octagons, in different sizes and speeds, and verify the control of the frequency of CO(2) jet stimuli.

Active Prior Tactile Knowledge Transfer for Learning Tactual Properties of New Objects

PubMed Central

Feng, Di

2018-01-01

Reusing the tactile knowledge of some previously-explored objects (prior objects) helps us to easily recognize the tactual properties of new objects. In this paper, we enable a robotic arm equipped with multi-modal artificial skin, like humans, to actively transfer the prior tactile exploratory action experiences when it learns the detailed physical properties of new objects. These experiences, or prior tactile knowledge, are built by the feature observations that the robot perceives from multiple sensory modalities, when it applies the pressing, sliding, and static contact movements on objects with different action parameters. We call our method Active Prior Tactile Knowledge Transfer (APTKT), and systematically evaluated its performance by several experiments. Results show that the robot improved the discrimination accuracy by around 10% when it used only one training sample with the feature observations of prior objects. By further incorporating the predictions from the observation models of prior objects as auxiliary features, our method improved the discrimination accuracy by over 20%. The results also show that the proposed method is robust against transferring irrelevant prior tactile knowledge (negative knowledge transfer). PMID:29466300

Connections between intraparietal sulcus and a sensorimotor network underpin sustained tactile attention.

PubMed

Goltz, Dominique; Gundlach, Christopher; Nierhaus, Till; Villringer, Arno; Müller, Matthias; Pleger, Burkhard

2015-05-20

Previous studies on sustained tactile attention draw conclusions about underlying cortical networks by averaging over experimental conditions without considering attentional variance in single trials. This may have formed an imprecise picture of brain processes underpinning sustained tactile attention. In the present study, we simultaneously recorded EEG-fMRI and used modulations of steady-state somatosensory evoked potentials (SSSEPs) as a measure of attentional trial-by-trial variability. Therefore, frequency-tagged streams of vibrotactile stimulations were simultaneously presented to both index fingers. Human participants were cued to sustain attention to either the left or right finger stimulation and to press a button whenever they perceived a target pulse embedded in the to-be-attended stream. In-line with previous studies, a classical general linear model (GLM) analysis based on cued attention conditions revealed increased activity mainly in somatosensory and cerebellar regions. Yet, parametric modeling of the BOLD response using simultaneously recorded SSSEPs as a marker of attentional trial-by-trial variability quarried the intraparietal sulcus (IPS). The IPS in turn showed enhanced functional connectivity to a modality-unspecific attention network. However, this was only revealed on the basis of cued attention conditions in the classical GLM. By considering attentional variability as captured by SSSEPs, the IPS showed increased connectivity to a sensorimotor network, underpinning attentional selection processes between competing tactile stimuli and action choices (press a button or not). Thus, the current findings highlight the potential value by considering attentional variations in single trials and extend previous knowledge on the role of the IPS in tactile attention. Copyright © 2015 the authors 0270-6474/15/357938-12$15.00/0.

Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

PubMed Central

Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Werkhoven, Peter

2014-01-01

Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance. PMID:25249947

Changes in passive tactile sensibility associated with dental implants following their placement.

PubMed

El-Sheikh, Ali M; Hobkirk, John A; Howell, Peter G T; Gilthorpe, Mark S

2003-01-01

This study investigated the changes that might occur in passive tactile sensibility during a period of 3 months following Implant placement in a group of edentulous subjects treated with dental implants. The effect of changing the velocity of force application on passive tactile sensibility was also investigated. Five edentulous subjects who had been treated (as a part of an immediate loading study) with 2 or more Nobel Biocare dental implants in the anterior mandible were studied. Pushing forces were applied directly and perpendicular to the long axes of the abutments until the subjects felt the first sensation of pressure, using a computer-controlled, custom-made device. The force was measured with an integral transducer. The applied force had a ramped staircase pattern, which was used at 2 different tip velocities. The measurements were taken on 4 occasions: 1, 2, 4, and 12 weeks after fitting the abutments. Statistical analysis, using multilevel modeling, demonstrated that there was a significant decrease In the tactile threshold over successive weeks following implant placement. It also demonstrated that high velocity exhibited a higher threshold than low velocity. It could be concluded that there was a significant increase In passive tactile sensibility during the healing phase following implant placement.

A flexible tactile sensitive sheet using a hetero-core fiber optic sensor

NASA Astrophysics Data System (ADS)

Fujino, S.; Yamazaki, H.; Hosoki, A.; Watanabe, K.

2014-05-01

In this report, we have designed a tactile sensitive sheet based on a hetero-core fiber-optic sensor, which realize an areal sensing by using single sensor potion in one optical fiber line. Recently, flexible and wide-area tactile sensing technology is expected to applied to acquired biological information in living space and robot achieve long-term care services such as welfare and nursing-care and humanoid technology. A hetero-core fiber-optic sensor has several advantages such as thin and flexible transmission line, immunity to EMI. Additionally this sensor is sensitive to moderate bending actions with optical loss changes and is independent of temperature fluctuation. Thus, the hetero-core fiber-optic sensor can be suitable for areal tactile sensing. We measure pressure characteristic of the proposed sensitive sheet by changing the pressure position and pinching characteristic on the surface. The proposed tactile sensitive sheet shows monotonic responses on the whole sensitive sheet surface although different sensitivity by the position is observed at the sensitive sheet surface. Moreover, the tactile sensitive sheet could sufficiently detect the pinching motion. In addition, in order to realize the discrimination between pressure and pinch, we fabricated a doubled-over sensor using a set of tactile sensitive sheets, which has different kinds of silicon robbers as a sensitive sheet surface. In conclusion, the flexible material could be given to the tactile sensation which is attached under proposed sensitive sheet.

Prestimulus Alpha Power Influences Tactile Temporal Perceptual Discrimination and Confidence in Decisions.

PubMed

Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

2016-03-01

Recent studies have demonstrated that prestimulus alpha-band activity substantially influences perception of near-threshold stimuli. Here, we studied the influence of prestimulus alpha power fluctuations on temporal perceptual discrimination of suprathreshold tactile stimuli and subjects' confidence regarding their perceptual decisions. We investigated how prestimulus alpha-band power influences poststimulus decision-making variables. We presented electrical stimuli with different stimulus onset asynchronies (SOAs) to human subjects, and determined the SOA for which temporal perceptual discrimination varied on a trial-by-trial basis between perceiving 1 or 2 stimuli, prior to recording brain activity with magnetoencephalography. We found that low prestimulus alpha power in contralateral somatosensory and occipital areas predicts the veridical temporal perceptual discrimination of 2 stimuli. Additionally, prestimulus alpha power was negatively correlated with confidence ratings in correctly perceived trials, but positively correlated for incorrectly perceived trials. Finally, poststimulus event-related fields (ERFs) were modulated by prestimulus alpha power and reflect the result of a decisional process rather than physical stimulus parameters around ∼150 ms. These findings provide new insights into the link between spontaneous prestimulus alpha power fluctuations, temporal perceptual discrimination, decision making, and decisional confidence. The results suggest that prestimulus alpha power modulates perception and decisions on a continuous scale, as reflected in confidence ratings. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Proprio-tactile integration for kinesthetic perception: an fMRI study.

PubMed

Kavounoudias, A; Roll, J P; Anton, J L; Nazarian, B; Roth, M; Roll, R

2008-01-31

This study aims to identify the cerebral networks involved in the integrative processing of somesthetic inputs for kinesthetic purposes. In particular, we investigated how muscle proprioceptive and tactile messages can result in a unified percept of one's own body movements. We stimulated either separately or conjointly these two sensory channels in order to evoke kinesthetic illusions of a clockwise rotation of 10 subjects' right hand in an fMRI environment. Results first show that, whether induced by a tactile or a proprioceptive stimulation, the kinesthetic illusion was accompanied by the activation of a very similar cerebral network including cortical and subcortical sensorimotor areas, which are also classically found in passive or imagined movement tasks. In addition, the strongest kinesthetic illusions occurred under the congruent proprio-tactile co-stimulation condition. They were specifically associated to brain area activations distinct from those evidenced under the unimodal stimulations: the inferior parietal lobule, the superior temporal sulcus, the insula-claustrum region, and the cerebellum. These findings support the hypothesis that heteromodal areas may subserve multisensory integrative mechanisms at cortical and subcortical levels. They also suggest the integrative processing might consist of detection of the spatial coherence between the two kinesthetic messages involving the inferior parietal lobule activity and of a detection of their temporal coincidence via a subcortical relay, the insula structure, usually linked to the relative synchrony of different stimuli. Finally, the involvement of the superior temporal sulcus in the feeling of biological movement and that of the cerebellum in the movement timing control are also discussed.

Computational Intelligence Techniques for Tactile Sensing Systems

PubMed Central

Gastaldo, Paolo; Pinna, Luigi; Seminara, Lucia; Valle, Maurizio; Zunino, Rodolfo

2014-01-01

Tactile sensing helps robots interact with humans and objects effectively in real environments. Piezoelectric polymer sensors provide the functional building blocks of the robotic electronic skin, mainly thanks to their flexibility and suitability for detecting dynamic contact events and for recognizing the touch modality. The paper focuses on the ability of tactile sensing systems to support the challenging recognition of certain qualities/modalities of touch. The research applies novel computational intelligence techniques and a tensor-based approach for the classification of touch modalities; its main results consist in providing a procedure to enhance system generalization ability and architecture for multi-class recognition applications. An experimental campaign involving 70 participants using three different modalities in touching the upper surface of the sensor array was conducted, and confirmed the validity of the approach. PMID:24949646

Computational intelligence techniques for tactile sensing systems.

PubMed

Gastaldo, Paolo; Pinna, Luigi; Seminara, Lucia; Valle, Maurizio; Zunino, Rodolfo

2014-06-19

Tactile sensing helps robots interact with humans and objects effectively in real environments. Piezoelectric polymer sensors provide the functional building blocks of the robotic electronic skin, mainly thanks to their flexibility and suitability for detecting dynamic contact events and for recognizing the touch modality. The paper focuses on the ability of tactile sensing systems to support the challenging recognition of certain qualities/modalities of touch. The research applies novel computational intelligence techniques and a tensor-based approach for the classification of touch modalities; its main results consist in providing a procedure to enhance system generalization ability and architecture for multi-class recognition applications. An experimental campaign involving 70 participants using three different modalities in touching the upper surface of the sensor array was conducted, and confirmed the validity of the approach.

An Experimental Optical Three-axis Tactile Sensor Featured with Hemispherical Surface

NASA Astrophysics Data System (ADS)

Ohka, Masahiro; Kobayashi, Hiroaki; Takata, Jumpei; Mitsuya, Yasunaga

We are developing an optical three-axis tactile sensor capable of acquiring normal and shearing force to mount on a robotic finger. The tactile sensor is based on the principle of an optical waveguide-type tactile sensor, which is composed of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the silicone rubber comprises one columnar feeler and eight conical feelers. The contact areas of the conical feelers, which maintain contact with the acrylic dome, detect the three-axis force applied to the tip of the sensing element. Normal and shearing forces are then calculated from integration and centroid displacement of the grayscale value derived from the conical feeler's contacts. To evaluate the present tactile sensor, we conducted a series of experiments using an x-z stage, a rotational stage, and a force gauge. Although we discovered that the relationship between the integrated grayscale value and normal force depends on the sensor's latitude on the hemispherical surface, it is easy to modify the sensitivity based on the latitude to make the centroid displacement of the grayscale value proportional to the shearing force. When we examined the repeatability of the present tactile sensor with 1,000 load/unload cycles, the error was 2%.

When Sandpaper Is 'Kiki' and Satin Is 'Bouba': an Exploration of the Associations Between Words, Emotional States, and the Tactile Attributes of Everyday Materials.

PubMed

Etzi, Roberta; Spence, Charles; Zampini, Massimiliano; Gallace, Alberto

2016-01-01

Over the last decade, scientists working on the topic of multisensory integration, as well as designers and marketers involved in trying to understand consumer behavior, have become increasingly interested in the non-arbitrary associations (e.g., sound symbolism) between different sensorial attributes of the stimuli they work with. Nevertheless, to date, little research in this area has investigated the presence of these crossmodal correspondences in the tactile evaluation of everyday materials. Here, we explore the presence and nature of the associations between tactile sensations, the sound of non-words, and people's emotional states. Samples of cotton, satin, tinfoil, sandpaper, and abrasive sponge, were stroked along the participants' forearm at the speed of 5 cm/s. Participants evaluated the materials along several dimensions, comprising scales anchored by pairs of non-words (e.g., Kiki/Bouba) and adjectives (e.g., ugly/beautiful). The results revealed that smoother textures were associated with non-words made up of round-shaped sounds (e.g., Maluma), whereas rougher textures were more strongly associated with sharp-transient sounds (e.g., Takete). The results also revealed the presence of a number of correspondences between tactile surfaces and adjectives related to visual and auditory attributes. For example, smooth textures were associated with features evoked by words such as 'bright' and 'quiet'; by contrast, the rougher textures were associated with adjectives such as 'dim' and 'loud'. The textures were also found to be associated with a number of emotional labels. Taken together, these results further our understanding of crossmodal correspondences involving the tactile modality and provide interesting insights in the applied field of design and marketing.

Spatially digitized tactile pressure sensors with tunable sensitivity and sensing range.

PubMed

Choi, Eunsuk; Sul, Onejae; Hwang, Soonhyung; Cho, Joonhyung; Chun, Hyunsuk; Kim, Hongjun; Lee, Seung-Beck

2014-10-24

When developing an electronic skin with touch sensation, an array of tactile pressure sensors with various ranges of pressure detection need to be integrated. This requires low noise, highly reliable sensors with tunable sensing characteristics. We demonstrate the operation of tactile pressure sensors that utilize the spatial distribution of contact electrodes to detect various ranges of tactile pressures. The device consists of a suspended elastomer diaphragm, with a carbon nanotube thin-film on the bottom, which makes contact with the electrodes on the substrate with applied pressure. The electrodes separated by set distances become connected in sequence with tactile pressure, enabling consecutive electrodes to produce a signal. Thus, the pressure is detected not by how much of a signal is produced but by which of the electrodes is registering an output. By modulating the diaphragm diameter, and suspension height, it was possible to tune the pressure sensitivity and sensing range. Also, adding a fingerprint ridge structure enabled the sensor to detect the periodicity of sub-millimeter grating patterns on a silicon wafer.

[On the improvement of discrimination of vibration stimuli by training in late aquired deafness (author's transl)].

PubMed

Schultz-Coulon, H J; Borghorst, U

1982-03-01

Acoustic signals of low frequencies can be percepted by the tactile sense as vibrations to a limited extent. In educating deaf children one takes trouble to combine tactile and visual speech perception in order to improve speech discrimination. The question of this study was, whether an improvement of tactile discrimination can be achieved even by patients with late aquired deafness. In a 45 years old female patient who had become deaf after adolescence the tactile discrimination of instrumental sounds (electric organ) within the frequency area c3-c4 (131-262 cps) as well as of speech sounds (30 mono- and multisyllabic words) was trained by means of the SIEMENS-Fonator. After two training courses of ten hours each (à 45 min) the patient was not only able to recognize pitch differences of two half steps and more as well as the tones of the scale with few errors only, but could also identify the words to a high percentage; in monosyllables she reached an identification rate of 75.6% and in words with 3 syllables of 85%. Additionally, a marked improvement of speech discrimination by lip reading was observed when using the Fonator. Accordingly, even in patients with late aquired deafness it appears to be worthwhile to train the tactile discrimination of vibration stimuli as to support lip reading.

Pain sensitivity and tactile spatial acuity are altered in healthy musicians as in chronic pain patients

PubMed Central

Zamorano, Anna M.; Riquelme, Inmaculada; Kleber, Boris; Altenmüller, Eckart; Hatem, Samar M.; Montoya, Pedro

2015-01-01

Extensive training of repetitive and highly skilled movements, as it occurs in professional classical musicians, may lead to changes in tactile sensitivity and corresponding cortical reorganization of somatosensory cortices. It is also known that professional musicians frequently experience musculoskeletal pain and pain-related symptoms during their careers. The present study aimed at understanding the complex interaction between chronic pain and music training with respect to somatosensory processing. For this purpose, tactile thresholds (mechanical detection, grating orientation, two-point discrimination) and subjective ratings to thermal and pressure pain stimuli were assessed in 17 professional musicians with chronic pain, 30 pain-free musicians, 20 non-musicians with chronic pain, and 18 pain-free non-musicians. We found that pain-free musicians displayed greater touch sensitivity (i.e., lower mechanical detection thresholds), lower tactile spatial acuity (i.e., higher grating orientation thresholds) and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. Moreover, we also found that musicians and non-musicians with chronic pain presented lower tactile spatial acuity and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. The significant increment of pain sensitivity together with decreased spatial discrimination in pain-free musicians and the similarity of results found in chronic pain patients, suggests that the extensive training of repetitive and highly skilled movements in classical musicians could be considered as a risk factor for developing chronic pain, probably due to use-dependent plastic changes elicited in somatosensory pathways. PMID:25610384

Tactile allodynia in patients with lumbar radicular pain (sciatica).

PubMed

Defrin, Ruth; Devor, Marshall; Brill, Silviu

2014-12-01

We report a novel symptom in many patients with low back pain (LBP) that sheds new light on the underlying pain mechanism. By means of quantitative sensory testing, we compared patients with radicular LBP (sciatica), axial LBP (LBP without radiation into the leg), and healthy controls, searching for cutaneous allodynia in response to weak tactile and cooling stimuli on the leg and low back. Most patients with radicular pain (~60%) reported static and dynamic tactile allodynia, as well as cooling allodynia, on the leg, often extending into the foot. Some also reported allodynia on the low back. In axial LBP, allodynia was almost exclusively on the back. The degree of dynamic tactile allodynia correlated with the degree of background pain. The presence of allodynia suggests that the peripheral nerve generators of background leg and back pain have also induced central sensitization. The distal (foot) location of the allodynia in patients who have it indicates that the nociceptive drive that maintains the central sensitization arises paraspinally (ectopically) in injured ventral ramus afferents; this is not an instance of somatic referred pain. The presence of central sensitization also provides the first cogent account of shooting pain in sciatica as a wave of activity sweeping vectorially across the width of the sensitized dorsal horn. Finally, the results endorse leg allodynia as a pain biomarker in animal research on LBP, which is commonly used but has not been previously validated. In addition to informing the underlying mechanism of LBP, bedside mapping of allodynia might have practical implications for prognosis and treatment. How can you tell whether pain radiating into the leg in a patient with sciatica is neuropathic, ie, due to nerve injury? Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Spatial cues serving the tactile directional sensibility of the human forearm.

PubMed Central

Norrsell, U; Olausson, H

1994-01-01

1. Tactile directional sensibility is considered to rely on the parallel processing of direction-contingent sensory data that depend on skin stretching caused by friction, and spatial cues that vary with time. A temperature-controlled airstream stimulus that prevented the activation of stretch receptors was used to investigate directional sensibility for the skin of the forearm. 2. The dependence on contact load and distance of movement was determined for normal subjects with a two-alternative forced-choice method. Testing was performed under two conditions, elbow bent or straight. Bracing the skin by straightening the arm did not alter the accuracy of the directional sensibility, in contrast to previous findings with stimuli that caused friction. 3. The accuracy of directional sensibility was correlated linearly to the logarithm of the distance of movement of the air jet. No correlation was found between accuracy and contact load, unlike findings with stimuli that cause friction. 4. Measurements were made with different subjects to determine the threshold distance at constant load. On average, subjects were able to distinguish direction with movements of < or = 8 mm. This acuity is sharper than has been reported with static stimuli. There was no correlation between subjects' threshold distances for judging direction and spatial acuity measured with absolute point localization. 5. The ability to distinguish direction was poor for the airstream stimulus compared with stimuli causing frictional contact with hairy skin. Nevertheless, the present findings are consistent with the suggestion that cutaneous spatial acuity is better for dynamic than for static stimuli. Images Figure 1 PMID:7965863

A flexible tactile-feedback touch screen using transparent ferroelectric polymer film vibrators

NASA Astrophysics Data System (ADS)

Ju, Woo-Eon; Moon, Yong-Ju; Park, Cheon-Ho; Choi, Seung Tae

2014-07-01

To provide tactile feedback on flexible touch screens, transparent relaxor ferroelectric polymer film vibrators were designed and fabricated in this study. The film vibrator can be integrated underneath a transparent cover film or glass, and can also produce acoustic waves that cause a tactile sensation on human fingertips. Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] polymer was used as the relaxor ferroelectric polymer because it produces a large strain under applied electric fields, shows a fast response, and has excellent optical transparency. The natural frequency of this tactile-feedback touch screen was designed to be around 200-240 Hz, at which the haptic perception of human fingertips is the most sensitive; therefore, the resonance of the touch screen at its natural frequency provides maximum haptic sensation. A multilayered relaxor ferroelectric polymer film vibrator was also demonstrated to provide the same vibration power at reduced voltage. The flexible P(VDF-TrFE-CTFE) film vibrators developed in this study are expected to provide tactile sensation not only in large-area flat panel displays, but also in flexible displays and touch screens.

Multisensory training can promote or impede visual perceptual learning of speech stimuli: visual-tactile vs. visual-auditory training.

PubMed

Eberhardt, Silvio P; Auer, Edward T; Bernstein, Lynne E

2014-01-01

In a series of studies we have been investigating how multisensory training affects unisensory perceptual learning with speech stimuli. Previously, we reported that audiovisual (AV) training with speech stimuli can promote auditory-only (AO) perceptual learning in normal-hearing adults but can impede learning in congenitally deaf adults with late-acquired cochlear implants. Here, impeder and promoter effects were sought in normal-hearing adults who participated in lipreading training. In Experiment 1, visual-only (VO) training on paired associations between CVCVC nonsense word videos and nonsense pictures demonstrated that VO words could be learned to a high level of accuracy even by poor lipreaders. In Experiment 2, visual-auditory (VA) training in the same paradigm but with the addition of synchronous vocoded acoustic speech impeded VO learning of the stimuli in the paired-associates paradigm. In Experiment 3, the vocoded AO stimuli were shown to be less informative than the VO speech. Experiment 4 combined vibrotactile speech stimuli with the visual stimuli during training. Vibrotactile stimuli were shown to promote visual perceptual learning. In Experiment 5, no-training controls were used to show that training with visual speech carried over to consonant identification of untrained CVCVC stimuli but not to lipreading words in sentences. Across this and previous studies, multisensory training effects depended on the functional relationship between pathways engaged during training. Two principles are proposed to account for stimulus effects: (1) Stimuli presented to the trainee's primary perceptual pathway will impede learning by a lower-rank pathway. (2) Stimuli presented to the trainee's lower rank perceptual pathway will promote learning by a higher-rank pathway. The mechanisms supporting these principles are discussed in light of multisensory reverse hierarchy theory (RHT).

Multisensory training can promote or impede visual perceptual learning of speech stimuli: visual-tactile vs. visual-auditory training

PubMed Central

Eberhardt, Silvio P.; Auer Jr., Edward T.; Bernstein, Lynne E.

2014-01-01

In a series of studies we have been investigating how multisensory training affects unisensory perceptual learning with speech stimuli. Previously, we reported that audiovisual (AV) training with speech stimuli can promote auditory-only (AO) perceptual learning in normal-hearing adults but can impede learning in congenitally deaf adults with late-acquired cochlear implants. Here, impeder and promoter effects were sought in normal-hearing adults who participated in lipreading training. In Experiment 1, visual-only (VO) training on paired associations between CVCVC nonsense word videos and nonsense pictures demonstrated that VO words could be learned to a high level of accuracy even by poor lipreaders. In Experiment 2, visual-auditory (VA) training in the same paradigm but with the addition of synchronous vocoded acoustic speech impeded VO learning of the stimuli in the paired-associates paradigm. In Experiment 3, the vocoded AO stimuli were shown to be less informative than the VO speech. Experiment 4 combined vibrotactile speech stimuli with the visual stimuli during training. Vibrotactile stimuli were shown to promote visual perceptual learning. In Experiment 5, no-training controls were used to show that training with visual speech carried over to consonant identification of untrained CVCVC stimuli but not to lipreading words in sentences. Across this and previous studies, multisensory training effects depended on the functional relationship between pathways engaged during training. Two principles are proposed to account for stimulus effects: (1) Stimuli presented to the trainee’s primary perceptual pathway will impede learning by a lower-rank pathway. (2) Stimuli presented to the trainee’s lower rank perceptual pathway will promote learning by a higher-rank pathway. The mechanisms supporting these principles are discussed in light of multisensory reverse hierarchy theory (RHT). PMID:25400566

Tactile Ranschburg effects: facilitation and inhibitory repetition effects analogous to verbal memory.

PubMed

Roe, Daisy; Miles, Christopher; Johnson, Andrew J

2017-07-01

The present paper examines the effect of within-sequence item repetitions in tactile order memory. Employing an immediate serial recall procedure, participants reconstructed a six-item sequence tapped upon their fingers by moving those fingers in the order of original stimulation. In Experiment 1a, within-sequence repetition of an item separated by two-intervening items resulted in a significant reduction in recall accuracy for that repeated item (i.e., the Ranschburg effect). In Experiment 1b, within-sequence repetition of an adjacent item resulted in significant recall facilitation for that repeated item. These effects mirror those reported for verbal stimuli (e.g., Henson, 1998a . Item repetition in short-term memory: Ranschburg repeated. Journal of Experimental Psychology: Learning, Memory, and Cognition, 24(5), 1162-1181. doi:doi.org/10.1037/0278-7393.24.5.1162). These data are the first to demonstrate the Ranschburg effect with non-verbal stimuli and suggest further cross-modal similarities in order memory.

Assessment of Dementia in Individuals with Dual Sensory Loss: Application of a Tactile Test Battery

PubMed Central

Bruhn, Peter; Dammeyer, Jesper

2018-01-01

Background/Aims Individuals with dual sensory loss (DSL) are more likely to experience cognitive decline with age than individuals without sensory loss. Other studies have pointed to the challenges in assessing cognitive abilities in individuals with DSL, as most existing instruments rely on use of vision and hearing. The aim of this study was to develop and evaluate a Tactile Test Battery (TTB) for cognitive assessment in individuals with DSL. Method Twenty elderly individuals with DSL, 20 with diagnosed dementia, and 20 without dementia or DSL (controls) completed the following tactile tests developed for the present study: Spatial learning, Spatial recall, Tactile form board, Clock reading, and Naming. The participants with dementia and controls also completed the Mini-Mental State Examination (MMSE). Results Overall, participants with dementia performed significantly worse on the tactile tests than participants with DSL and control participants. No significant differences on the tactile tests were found between participants with DSL and controls. The TTB and MMSE scores correlated significantly. Conclusion The findings from this study of applying tactile tests for cognitive examination in individuals with DSL are promising. They indicate that symptoms of dementia can be differentiated from symptoms related to DSL. PMID:29515619

Compliant tactile sensor that delivers a force vector

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2010-01-01

Tactile Sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector. The applied force vector has three components to establish the direction and magnitude of an applied force. The compliant convex surface defines a dome with a hollow interior and has a linear relation between displacement and load including a magnet disposed substantially at the center of the dome above a sensor array that responds to magnetic field intensity.

Linkage between Free Exploratory Movements and Subjective Tactile Ratings.

PubMed

Yokosaka, Takumi; Kuroki, Scinob; Watanabe, Junji; Nishida, Shinya

2017-01-01

We actively move our hands and eyes when exploring the external world and gaining information about object's attributes. Previous studies showing that how we touch might be related to how we felt led us to consider whether we could decode observers' subjective tactile experiences only by analyzing their exploratory movements without explicitly asking how they perceived. However, in those studies, explicit judgment tasks were performed about specific tactile attributes that were prearranged by experimenters. Here, we systematically investigated whether exploratory movements can explain tactile ratings even when participants do not need to judge any tactile attributes. While measuring both hand and eye movements, we asked participants to touch materials freely without judging any specific tactile attributes (free-touch task) or to evaluate one of four tactile attributes (roughness, hardness, slipperiness, and temperature). We found that tactile ratings in the judgment tasks correlated with exploratory movements even in the free-touch task and that eye movements as well as hand movements correlated with tactile ratings. These results might open up the possibility of decoding tactile experiences by exploratory movements.

Exploration of the Effectiveness of Tactile Methods

ERIC Educational Resources Information Center

Aldajani, Neda F.

2016-01-01

This paper introduces the tactile method and aims to explore the effectiveness of using tactile methods with students who are blind and visually impaired. Although there was limited research about using this strategy, all of the research agrees that using tactile is one of the best ways for students who are blind and visually impaired to be…

The role of tactile feedback in grip force during laparoscopic training tasks.

PubMed

Wottawa, Christopher R; Cohen, Jeremiah R; Fan, Richard E; Bisley, James W; Culjat, Martin O; Grundfest, Warren S; Dutson, Erik P

2013-04-01

Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques. A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control. After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases). Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.

Fingertip-shaped optical tactile sensor for robotic applications

NASA Technical Reports Server (NTRS)

Begej, Stefan

1988-01-01

Progress is described regarding the development of a high-density, fiber-optic, fingertip-shaped tactile sensor specifically designed for application to dexterous robotics. The sensor operates on optical principles involving the frustration of total internal reflection at a waveguide/elastomer interface and generates a grey-scale tactile image that represents the normal forces of contact. The sensor contains 256 taxels (sensing sites) distributed in a dual-density pattern that includes a tactile fovea near the tip which measures 13 mm x 13 mm and contains 169 taxels. The details regarding the design and construction of this tactile sensor are presented, in addition to photographs of tactile imprints.

Summary of Tactile User Interfaces Techniques and Systems

NASA Technical Reports Server (NTRS)

Spirkovska, Lilly

2005-01-01

Mental workload can be de.ned as the ratio of demand to allocated resources. Multiple-resource theory stresses the importance of distribution of tasks and information across various human sensory channels to reduce mental workload. One sensory channel that has been of interest since the late 1800s is touch. Unlike the more typical displays that target vision or hearing, tactile displays present information to the user s sense of touch. We present a summary of different methods for tactile display, historic and more recent systems that incorporate tactile display for information presentation, advantages and disadvantages of targeting the tactile channel, and future directions in tactile display research.

Summary of Tactile User Interfaces Techniques and Systems

NASA Technical Reports Server (NTRS)

Spirkovska, Lilly

2004-01-01

Mental workload can be defined as the ratio of demand to allocated resources. Multiple- resource theory stresses the importance of distribution of tasks and information across various sensory channels of the human to reduce mental workload. One sensory channel that has been of interest since the late 1800s is touch. Unlike the more typical displays that target vision or hearing, tactile displays present information to the user s sense of touch. We present a summary of different methods for tactile display; historic and more recent systems that incorporate tactile display for information presentation; advantages and disadvantages of targeting the tactile channel; and future directions in tactile display research.

A Tactile Carina Nebula

NASA Astrophysics Data System (ADS)

Grice, Noreen A.; Mutchler, M.

2010-01-01

Astronomy was once considered a science restricted to fully sighted participants. But in the past two decades, accessible books with large print/Braille and touchable pictures have brought astronomy and space science to the hands and mind's eye of students, regardless of their visual ability. A new universally-designed tactile image featuring the Hubble mosaic of the Carina Nebula is being presented at this conference. The original dataset was obtained with Hubble's Advanced Camera for Surveys (ACS) hydrogen-alpha filter in 2005. It became an instant icon after being infused with additional color information from ground-based CTIO data, and released as Hubble's 17th anniversary image. Our tactile Carina Nebula promotes multi-mode learning about the entire life-cycle of stars, which is dramatically illustrated in this Hubble mosaic. When combined with descriptive text in print and Braille, the visual and tactile components seamlessly reach both sighted and blind populations. Specific touchable features of the tactile image identify the shapes and orientations of objects in the Carina Nebula that include star-forming regions, jets, pillars, dark and light globules, star clusters, shocks/bubbles, the Keyhole Nebula, and stellar death (Eta Carinae). Visit our poster paper to touch the Carina Nebula!

INFANT AVOIDANCE DURING A TACTILE TASK PREDICTS AUTISM SPECTRUM BEHAVIORS IN TODDLERHOOD.

PubMed

Mammen, Micah A; Moore, Ginger A; Scaramella, Laura V; Reiss, David; Ganiban, Jody M; Shaw, Daniel S; Leve, Leslie D; Neiderhiser, Jenae M

2015-01-01

The experience of touch is critical for early communication and social interaction; infants who show aversion to touch may be at risk for atypical development and behavior problems. The current study aimed to clarify predictive associations between infant responses to tactile stimuli and toddler autism spectrum, internalizing, and externalizing behaviors. This study measured 9-month-old infants' (N = 561; 58% male) avoidance and negative affect during a novel tactile task in which parents painted infants' hands and feet and pressed them to paper to make a picture. Parent reports on the Pervasive Developmental Problems (PDP), Internalizing, and Externalizing scales of the Child Behavior Checklist were used to measure toddler behaviors at 18 months. Infant observed avoidance and negative affect were significantly correlated; however, avoidance predicted subsequent PDP scores only, independent of negative affect, which did not predict any toddler behaviors. Findings suggest that incorporating measures of responses to touch in the study of early social interaction may provide an important and discriminating construct for identifying children at greater risk for social impairments related to autism spectrum behaviors. © 2015 Michigan Association for Infant Mental Health.

Auditory and tactile gap discrimination by observers with normal and impaired hearing.

PubMed

Desloge, Joseph G; Reed, Charlotte M; Braida, Louis D; Perez, Zachary D; Delhorne, Lorraine A; Villabona, Timothy J

2014-02-01

Temporal processing ability for the senses of hearing and touch was examined through the measurement of gap-duration discrimination thresholds (GDDTs) employing the same low-frequency sinusoidal stimuli in both modalities. GDDTs were measured in three groups of observers (normal-hearing, hearing-impaired, and normal-hearing with simulated hearing loss) covering an age range of 21-69 yr. GDDTs for a baseline gap of 6 ms were measured for four different combinations of 100-ms leading and trailing markers (250-250, 250-400, 400-250, and 400-400 Hz). Auditory measurements were obtained for monaural presentation over headphones and tactile measurements were obtained using sinusoidal vibrations presented to the left middle finger. The auditory GDDTs of the hearing-impaired listeners, which were larger than those of the normal-hearing observers, were well-reproduced in the listeners with simulated loss. The magnitude of the GDDT was generally independent of modality and showed effects of age in both modalities. The use of different-frequency compared to same-frequency markers led to a greater deterioration in auditory GDDTs compared to tactile GDDTs and may reflect differences in bandwidth properties between the two sensory systems.

Biologically inspired multi-layered synthetic skin for tactile feedback in prosthetic limbs.

PubMed

Osborn, Luke; Nguyen, Harrison; Betthauser, Joseph; Kaliki, Rahul; Thakor, Nitish

2016-08-01

The human body offers a template for many state-of-the-art prosthetic devices and sensors. In this work, we present a novel, sensorized synthetic skin that mimics the natural multi-layered nature of mechanoreceptors found in healthy glabrous skin to provide tactile information. The multi-layered sensor is made up of flexible piezoresistive textiles that act as force sensitive resistors (FSRs) to convey tactile information, which are embedded within a silicone rubber to resemble the compliant nature of human skin. The top layer of the synthetic skin is capable of detecting small loads less than 5 N whereas the bottom sensing layer responds reliably to loads over 7 N. Finite element analysis (FEA) of a simplified human fingertip and the synthetic skin was performed. Results suggest similarities in behavior during loading. A natural tactile event is simulated by loading the synthetic skin on a prosthetic limb. Results show the sensors' ability to detect applied loads as well as the ability to simulate neural spiking activity based on the derivative and temporal differences of the sensor response. During the tactile loading, the top sensing layer responded 0.24 s faster than the bottom sensing layer. A synthetic biologically-inspired skin such as this will be useful for enhancing the functionality of prosthetic limbs through tactile feedback.

Development of CMOS MEMS inductive type tactile sensor with the integration of chrome steel ball force interface

NASA Astrophysics Data System (ADS)

Yeh, Sheng-Kai; Chang, Heng-Chung; Fang, Weileun

2018-04-01

This study presents an inductive tactile sensor with a chrome steel ball sensing interface based on the commercially available standard complementary metal-oxide-semiconductor (CMOS) process (the TSMC 0.18 µm 1P6M CMOS process). The tactile senor has a deformable polymer layer as the spring of the device and no fragile suspended thin film structures are required. As a tactile force is applied on the chrome steel ball, the polymer would deform. The distance between the chrome steel ball and the sensing coil would changed. Thus, the tactile force can be detected by the inductance change of the sensing coil. In short, the chrome steel ball acts as a tactile bump as well as the sensing interface. Experimental results show that the proposed inductive tactile sensor has a sensing range of 0-1.4 N with a sensitivity of 9.22(%/N) and nonlinearity of 2%. Preliminary wireless sensing test is also demonstrated. Moreover, the influence of the process and material issues on the sensor performances have also been investigated.

Tactile feedback for relief of deafferentation pain using virtual reality system: a pilot study.

PubMed

Sano, Yuko; Wake, Naoki; Ichinose, Akimichi; Osumi, Michihiro; Oya, Reishi; Sumitani, Masahiko; Kumagaya, Shin-Ichiro; Kuniyoshi, Yasuo

2016-06-28

Previous studies have tried to relieve deafferentation pain (DP) by using virtual reality rehabilitation systems. However, the effectiveness of multimodal sensory feedback was not validated. The objective of this study is to relieve DP by neurorehabilitation using a virtual reality system with multimodal sensory feedback and to validate the efficacy of tactile feedback on immediate pain reduction. We have developed a virtual reality rehabilitation system with multimodal sensory feedback and applied it to seven patients with DP caused by brachial plexus avulsion or arm amputation. The patients executed a reaching task using the virtual phantom limb manipulated by their real intact limb. The reaching task was conducted under two conditions: one with tactile feedback on the intact hand and one without. The pain intensity was evaluated through a questionnaire. We found that the task with the tactile feedback reduced DP more (41.8 ± 19.8 %) than the task without the tactile feedback (28.2 ± 29.5 %), which was supported by a Wilcoxon signed-rank test result (p < 0.05). Overall, our findings indicate that the tactile feedback improves the immediate pain intensity through rehabilitation using our virtual reality system.

Vibration-enhanced posture stabilization achieved by tactile supplementation: may blind individuals get extra benefits?

PubMed

Magalhães, Fernando Henrique; Kohn, André Fabio

2011-08-01

Diminished balance ability poses a serious health risk due to the increased likelihood of falling, and impaired postural stability is significantly associated with blindness and poor vision. Noise stimulation (by improving the detection of sub-threshold somatosensory information) and tactile supplementation (i.e., additional haptic information provided by an external contact surface) have been shown to improve the performance of the postural control system. Moreover, vibratory noise added to the source of tactile supplementation (e.g., applied to a surface that the fingertip touches) has been shown to enhance balance stability more effectively than tactile supplementation alone. In view of the above findings, in addition to the well established consensus that blind subjects show superior abilities in the use of tactile information, we hypothesized that blind subjects may take extra benefits from the vibratory noise added to the tactile supplementation and hence show greater improvements in postural stability than those observed for sighted subjects. If confirmed, this hypothesis may lay the foundation for the development of noise-based assistive devices (e.g., canes, walking sticks) for improving somatosensation and hence prevent falls in blind individuals. Copyright © 2011 Elsevier Ltd. All rights reserved.

Tactile communication.

DOT National Transportation Integrated Search

1962-05-01

Tactile communication presents a relatively unexploited channel of information transmission in the field of aviation. Visual and auditory input channels frequently reach an information saturation point during various flight operations. A cutaneous co...

Viewing the body modulates tactile receptive fields.

PubMed

Haggard, Patrick; Christakou, Anastasia; Serino, Andrea

2007-06-01

Tactile discrimination performance depends on the receptive field (RF) size of somatosensory cortical (SI) neurons. Psychophysical masking effects can reveal the RF of an idealized "virtual" somatosensory neuron. Previous studies show that top-down factors strongly affect tactile discrimination performance. Here, we show that non-informative vision of the touched body part influences tactile discrimination by modulating tactile RFs. Ten subjects performed spatial discrimination between touch locations on the forearm. Performance was improved when subjects saw their forearm compared to viewing a neutral object in the same location. The extent of visual information was relevant, since restricted view of the forearm did not have this enhancing effect. Vibrotactile maskers were placed symmetrically on either side of the tactile target locations, at two different distances. Overall, masking significantly impaired discrimination performance, but the spatial gradient of masking depended on what subjects viewed. Viewing the body reduced the effect of distant maskers, but enhanced the effect of close maskers, as compared to viewing a neutral object. We propose that viewing the body improves functional touch by sharpening tactile RFs in an early somatosensory map. Top-down modulation of lateral inhibition could underlie these effects.

Tactility and the body in early Chinese medicine.

PubMed

Hsu, Elisabeth

2005-03-01

If visual inspection of corpses was central to the development of anatomy in modern Europe, one may ask which of the senses was important for the emergence of the predominant currents of scholarly medical knowledge and practice in third- and second-century B.C.E. China? This article argues that it was tactile perception prompted by a tactile exploration of living bodies. The evidence, derived from a close reading of the Mawangdui medical manuscripts, the 105th chapter of the Records of the Historian, and selected passages from the Huang Di's Inner Canon, points to three important trends: first, the tactile exploration of the extremities led to a rich vocabulary of compound words for pain as localized in specific body parts; second, the tactile exploration of the mai gave rise to an even richer vocabulary on qualities of touch in pulse diagnostics; and third, the tactile exploration of the abdomen led to the assessment of the quality of the internal viscera with words that generally were used for describing the tactile quality of skin and flesh. This finding may appear surprising in the light of later developments during the dynastic history of Chinese medicine where tactile exploration of abdomen and extremities would appear unseemly. The author suggests that extensive tactile explorations of the body were possible before Confucius' teachings became a predominant aspect of state ideology.

Learning tactile skills through curious exploration

PubMed Central

Pape, Leo; Oddo, Calogero M.; Controzzi, Marco; Cipriani, Christian; Förster, Alexander; Carrozza, Maria C.; Schmidhuber, Jürgen

2012-01-01

We present curiosity-driven, autonomous acquisition of tactile exploratory skills on a biomimetic robot finger equipped with an array of microelectromechanical touch sensors. Instead of building tailored algorithms for solving a specific tactile task, we employ a more general curiosity-driven reinforcement learning approach that autonomously learns a set of motor skills in absence of an explicit teacher signal. In this approach, the acquisition of skills is driven by the information content of the sensory input signals relative to a learner that aims at representing sensory inputs using fewer and fewer computational resources. We show that, from initially random exploration of its environment, the robotic system autonomously develops a small set of basic motor skills that lead to different kinds of tactile input. Next, the system learns how to exploit the learned motor skills to solve supervised texture classification tasks. Our approach demonstrates the feasibility of autonomous acquisition of tactile skills on physical robotic platforms through curiosity-driven reinforcement learning, overcomes typical difficulties of engineered solutions for active tactile exploration and underactuated control, and provides a basis for studying developmental learning through intrinsic motivation in robots. PMID:22837748

Trigeminal activation using chemical, electrical, and mechanical stimuli.

PubMed

Iannilli, E; Del Gratta, C; Gerber, J C; Romani, G L; Hummel, T

2008-10-15

Tactile, proprioceptive, and nociceptive information, including also chemosensory functions are expressed in the trigeminal nerve sensory response. To study differences in the processing of different stimulus qualities, we performed a study based on functional magnetic resonance imaging. The first trigeminal branch (ophthalmic nerve) was activated by (a) intranasal chemical stimulation with gaseous CO2 which produces stinging and burning sensations, but is virtually odorless, (b) painful, but not nociceptive specific cutaneous electrical stimulation, and (c) cutaneous mechanical stimulation using air puffs. Eighteen healthy subjects participated (eight men, 10 women, mean age 31 years). Painful stimuli produced patterns of activation similar to what has been reported for other noxious stimuli, namely activation in the primary and secondary somatosensory cortices, anterior cingulate cortex, insular cortex, and thalamus. In addition, analyses indicated intensity-related activation in the prefrontal cortex which was specifically involved in the evaluation of stimulus intensity. Importantly, the results also indicated similarities between activation patterns after intranasal chemosensory trigeminal stimulation and patterns usually found following intranasal odorous stimulation, indicating the intimate connection between these two systems in the processing of sensory information.

Tactile and bone-conduction auditory brain computer interface for vision and hearing impaired users.

PubMed

Rutkowski, Tomasz M; Mori, Hiromu

2015-04-15

The paper presents a report on the recently developed BCI alternative for users suffering from impaired vision (lack of focus or eye-movements) or from the so-called "ear-blocking-syndrome" (limited hearing). We report on our recent studies of the extents to which vibrotactile stimuli delivered to the head of a user can serve as a platform for a brain computer interface (BCI) paradigm. In the proposed tactile and bone-conduction auditory BCI novel multiple head positions are used to evoke combined somatosensory and auditory (via the bone conduction effect) P300 brain responses, in order to define a multimodal tactile and bone-conduction auditory brain computer interface (tbcaBCI). In order to further remove EEG interferences and to improve P300 response classification synchrosqueezing transform (SST) is applied. SST outperforms the classical time-frequency analysis methods of the non-linear and non-stationary signals such as EEG. The proposed method is also computationally more effective comparing to the empirical mode decomposition. The SST filtering allows for online EEG preprocessing application which is essential in the case of BCI. Experimental results with healthy BCI-naive users performing online tbcaBCI, validate the paradigm, while the feasibility of the concept is illuminated through information transfer rate case studies. We present a comparison of the proposed SST-based preprocessing method, combined with a logistic regression (LR) classifier, together with classical preprocessing and LDA-based classification BCI techniques. The proposed tbcaBCI paradigm together with data-driven preprocessing methods are a step forward in robust BCI applications research. Copyright © 2014 Elsevier B.V. All rights reserved.

Mislocalization of tactile stimuli applied to the trunk in spatial neglect.

PubMed

Rousseaux, Marc; Sauer, Angéline; Saj, Arnaud; Bernati, Thérèse; Honoré, Jacques

2013-01-01

In patients with spatial neglect, body perception and representation are impaired - especially the projection of the anterior body midline in anterior space (the subjective "straight ahead"). However, data on more lateral body parts and the posterior body surface are scarce. We explored deviations of the perception of different body points located to the left or right of the midline and on the anterior and posterior body surfaces, and their lesion correlates in right hemisphere stroke patients. Nine patients with neglect (diagnosed with paper and pencil and behavioural tests) were compared with six non-neglect patients and 13 healthy controls. The subjects had to use a mannequin to designate the body location that had been stimulated by a blunt pencil tip. Four horizontally arranged series of locations were traced on the anterior and posterior body surfaces at shoulder and navel levels. Each horizontal series comprised five equidistant test points, from left to right and corresponded to eleven labelled points on the mannequin. Patient errors were confronted to their anatomic lesions (MRI). We found a significant (p ≤ .05) rightward deviation of the left-side points and midpoint and a significant leftward deviation of the right-most point in neglect patients. Non-neglect patients and control subjects designated all the test points accurately. The body side (anterior or posterior) and the line (shoulder or navel) did not influence performance. Controls showed a definite reduction in variability for the midline points, which disappeared in neglect patients who showed a severe global increase of this variability. Errors depended on lesions centred on the intraparietal sulcus. These observations were compatible with a complex bias in body perception-representation extending to various lateral body points, with a left to right gradient. The right parietal cortex likely participates in processing such information. Copyright © 2013 Elsevier Ltd. All rights reserved.

Attenuation of acoustic and tactile startle responses of vitamin B-6 deficient rats.

PubMed

Schaeffer, M C

1987-01-01

Vitamin B-6 deficient rats exhibit changes in behavior, sensory function, and other nervous system abnormalities such as convulsive seizures and motor disturbances. Sensorimotor reactivity was evaluated quantitatively by measuring auditory and tactile startle responses in 12 week old female Long-Evans rats fed a diet devoid of added vitamin B-6 (DEF) or a control diet, either ad lib (AL-CON) or pair-fed to deficient rats (PF-CON). Deficiency was confirmed with a tryptophan-load test administered to a separate group of rats fed simultaneously according to the same protocol. At week 18, body weight and feed efficiency were different among groups (p less than 0.001), and were lowest in DEF. Amplitude of response to both acoustic and tactile stimuli was depressed in DEF compared to both control groups, which generally did not differ in response. This effect was seen most dramatically in responses to the acoustic stimulus (p = 0.034), and especially to the first presentation (p = 0.017). Latency to maximum response was not affected by diet. Possible mechanisms for this nervous system abnormality, not previously reported in vitamin B-6 deficiency, are discussed.

Overt use of a tactile-kinesthetic strategy shifts to covert processing in rehabilitation of letter-by-letter reading.

PubMed

Lott, Susan Nitzberg; Carney, Aimee Syms; Glezer, Laurie S; Friedman, Rhonda B

2010-11-01

BACKGROUND: Letter-by-letter readers identify each letter of the word they are reading serially in left to right order before recognizing the word. When their letter naming is also impaired, letter-by-letter reading is inaccurate and can render even single word reading very poor. Tactile and/or kinesthetic strategies have been reported to improve reading in these patients, but only under certain conditions or for a limited set of stimuli. AIMS: The primary aim of the current study was to determine whether a tactile/kinesthetic treatment could significantly improve reading specifically under normal reading conditions, i.e. reading untrained words presented in free vision and read without overt use of the strategy. METHODS #ENTITYSTARTX00026; PROCEDURES: Three chronic letter-by-letter readers participated in a tactile/kinesthetic treatment aimed at first improving letter naming accuracy (phase 1) and then letter-by-letter reading speed (phase 2). In a multiple case series design, accuracy and speed of reading untrained words without overt use of the trained tactile/kinesthetic strategy was assessed before phase 1, after phase 1 and again after phase 2. OUTCOMES #ENTITYSTARTX00026; RESULTS: All three patients significantly improved both their speed and accuracy reading untrained words without overt use of the trained tactile/kinesthetic strategy. All three patients required the additional practice in phase 2 to achieve significant improvement. Treatment did not target sentence level reading, yet two of the three patients became so adept that they could read entire sentences. CONCLUSIONS: This study replicates previous findings on the efficacy of tactile/kinesthetic treatment for letter-by-letter readers with poor letter naming. It further demonstrates that this treatment can alter cognitive processing such that words never specifically trained can be read in free vision without overtly using the trained strategy. The data suggest that an important element in achieving

Overt use of a tactile-kinesthetic strategy shifts to covert processing in rehabilitation of letter-by-letter reading

PubMed Central

Lott, Susan Nitzberg; Carney, Aimee Syms; Glezer, Laurie S.; Friedman, Rhonda B.

2010-01-01

Background Letter-by-letter readers identify each letter of the word they are reading serially in left to right order before recognizing the word. When their letter naming is also impaired, letter-by-letter reading is inaccurate and can render even single word reading very poor. Tactile and/or kinesthetic strategies have been reported to improve reading in these patients, but only under certain conditions or for a limited set of stimuli. Aims The primary aim of the current study was to determine whether a tactile/kinesthetic treatment could significantly improve reading specifically under normal reading conditions, i.e. reading untrained words presented in free vision and read without overt use of the strategy. Methods & Procedures Three chronic letter-by-letter readers participated in a tactile/kinesthetic treatment aimed at first improving letter naming accuracy (phase 1) and then letter-by-letter reading speed (phase 2). In a multiple case series design, accuracy and speed of reading untrained words without overt use of the trained tactile/kinesthetic strategy was assessed before phase 1, after phase 1 and again after phase 2. Outcomes & Results All three patients significantly improved both their speed and accuracy reading untrained words without overt use of the trained tactile/kinesthetic strategy. All three patients required the additional practice in phase 2 to achieve significant improvement. Treatment did not target sentence level reading, yet two of the three patients became so adept that they could read entire sentences. Conclusions This study replicates previous findings on the efficacy of tactile/kinesthetic treatment for letter-by-letter readers with poor letter naming. It further demonstrates that this treatment can alter cognitive processing such that words never specifically trained can be read in free vision without overtly using the trained strategy. The data suggest that an important element in achieving this level of generalization is

Neural timing signal for precise tactile timing judgments

PubMed Central

Watanabe, Junji; Nishida, Shin'ya

2016-01-01

The brain can precisely encode the temporal relationship between tactile inputs. While behavioural studies have demonstrated precise interfinger temporal judgments, the underlying neural mechanism remains unknown. Computationally, two kinds of neural responses can act as the information source. One is the phase-locked response to the phase of relatively slow inputs, and the other is the response to the amplitude change of relatively fast inputs. To isolate the contributions of these components, we measured performance of a synchrony judgment task for sine wave and amplitude-modulation (AM) wave stimuli. The sine wave stimulus was a low-frequency sinusoid, with the phase shifted in the asynchronous stimulus. The AM wave stimulus was a low-frequency sinusoidal AM of a 250-Hz carrier, with only the envelope shifted in the asynchronous stimulus. In the experiment, three stimulus pairs, two synchronous ones and one asynchronous one, were sequentially presented to neighboring fingers, and participants were asked to report which one was the asynchronous pair. We found that the asynchrony of AM waves could be detected as precisely as single impulse pair, with the threshold asynchrony being ∼20 ms. On the other hand, the asynchrony of sine waves could not be detected at all in the range from 5 to 30 Hz. Our results suggest that the timing signal for tactile judgments is provided not by the stimulus phase information but by the envelope of the response of the high-frequency-sensitive Pacini channel (PC), although they do not exclude a possible contribution of the envelope of non-PCs. PMID:26843600

Fully printed flexible fingerprint-like three-axis tactile and slip force and temperature sensors for artificial skin.

PubMed

Harada, Shingo; Kanao, Kenichiro; Yamamoto, Yuki; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2014-12-23

A three-axis tactile force sensor that determines the touch and slip/friction force may advance artificial skin and robotic applications by fully imitating human skin. The ability to detect slip/friction and tactile forces simultaneously allows unknown objects to be held in robotic applications. However, the functionalities of flexible devices have been limited to a tactile force in one direction due to difficulties fabricating devices on flexible substrates. Here we demonstrate a fully printed fingerprint-like three-axis tactile force and temperature sensor for artificial skin applications. To achieve economic macroscale devices, these sensors are fabricated and integrated using only printing methods. Strain engineering enables the strain distribution to be detected upon applying a slip/friction force. By reading the strain difference at four integrated force sensors for a pixel, both the tactile and slip/friction forces can be analyzed simultaneously. As a proof of concept, the high sensitivity and selectivity for both force and temperature are demonstrated using a 3×3 array artificial skin that senses tactile, slip/friction, and temperature. Multifunctional sensing components for a flexible device are important advances for both practical applications and basic research in flexible electronics.

A tactile stimulus applied to the leg improves postural stability in young, old and neuropathic subjects.

PubMed

Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C

2006-10-02

The purpose of this study was to determine whether the application of passive tactile cues to the lower limb could improve postural stability in healthy young controls, older people and people with diabetic peripheral neuropathy. Antero-posterior sway was measured with eyes open and closed in 10 healthy young subjects (mean age 27 years, 5 male, 5 female), 10 older subjects without diabetic peripheral neuropathy (mean age 88 years, 2 male, 8 female) and 10 subjects with diabetic peripheral neuropathy (mean age 65 years, 6 male, 4 female) while a small piece of Velcro attached to a flexible mount was applied to three different sites on the leg (ankle, calf, and knee). Across all conditions, the mean sway of the neuropathic subjects was 93% greater than for the young subjects and 11% more than the older subjects. On average, subjects swayed 10% more with the eyes closed than with the eyes open. Each stimulus reduced sway, but the effect increased approximately in proportion to the height of the stimulus above the ankles (ankle 7.6%, calf 13.5%, knee 20.1% reduction compared to the no stimulus condition). This experiment demonstrates that a passive stimulus applied to the skin of the leg, which provides sensory information about body movement, significantly reduces body sway during standing. This applies to older subjects and subjects with peripheral neuropathy as well as healthy young subjects. These results have implications for novel approaches for improving stability in people with peripheral sensory loss.

Development of multichannel soft tactile sensors having fingerprint structure.

PubMed

Tsutsui, H; Murashima, Y; Honma, N; Kobayashi, K

2014-01-01

It is possible to accurately recognize the shape of an object or to grip it by setting soft tactile sensors on a robot's hands. We studied a multichannel soft tactile sensor as an artificial hand and evaluated the pressure's response performance from several directions and the slipping and sliding responses. The tactile sensor consisted of multiple pneumatic sensors and a soft cap with a fingerprint structure that was made of silicone gum and was separated from multiple spaces. Evaluation tests showed that the multiple soft tactile sensors estimate both an object's contact force and its contact location. Our tactile sensor also measured the object's roughness by the slide on surface texture.

The Design of Tactile Thematic Symbols

ERIC Educational Resources Information Center

Lawrence, Megan M.; Lobben, Amy K.

2011-01-01

The study reported here investigated the design and legibility of tactile thematic maps, focusing on symbolization and the comprehension of spatial patterns on the maps. The results indicate that discriminable and effective tactile thematic maps can be produced using classed data with a microcapsule paper production method. The participants…

Misunderstanding and Repair in Tactile Auslan

ERIC Educational Resources Information Center

Willoughby, Louisa; Manns, Howard; Iwasaki, Shimako; Bartlett, Meredith

2014-01-01

This article discusses ways in which misunderstandings arise in Tactile Australian Sign Language (Tactile Auslan) and how they are resolved. Of particular interest are the similarities to and differences from the same processes in visually signed and spoken conversation. This article draws on detailed conversation analysis (CA) and demonstrates…

Crossmodal Congruency Benefits of Tactile and Visual Signalling

DTIC Science & Technology

2013-11-12

modal information format seemed to produce faster and more accurate performance. The question of learning complex tactile communication signals...SECURITY CLASSIFICATION OF: We conducted an experiment in which tactile messages were created based on five common military arm and hand signals. We...compared response times and accuracy rates of novice individuals responding to visual and tactile representations of these messages, which were

Observing the Use of Tactile Schedules

ERIC Educational Resources Information Center

Aasen, Gro; Naerland, Terje

2014-01-01

This article explores the use of tactile schedules in a heterogeneous sample of children with congenital blindness and varying degrees of additional disabilities. Basic conditions for the use of tactile schedules are proposed and discussed. Child behaviour indicative of some particular functions that can be attained with the use of tactile…

Subject-level differences in reported locations of cutaneous tactile and nociceptive stimuli

PubMed Central

Steenbergen, Peter; Buitenweg, Jan R.; Trojan, Jörg; Klaassen, Bart; Veltink, Peter H.

2012-01-01

Recent theoretical advances on the topic of body representations have raised the question whether spatial perception of touch and nociception involve the same representations. Various authors have established that subjective localizations of touch and nociception are displaced in a systematic manner. The relation between veridical stimulus locations and localizations can be described in the form of a perceptual map; these maps differ between subjects. Recently, evidence was found for a common set of body representations to underlie spatial perception of touch and slow and fast pain, which receive information from modality specific primary representations. There are neurophysiological clues that the various cutaneous senses may not share the same primary representation. If this is the case, then differences in primary representations between touch and nociception may cause subject-dependent differences in perceptual maps of these modalities. We studied localization of tactile and nociceptive sensations on the forearm using electrocutaneous stimulation. The perceptual maps of these modalities differed at the group level. When assessed for individual subjects, the differences localization varied in nature between subjects. The agreement of perceptual maps of the two modalities was moderate. These findings are consistent with a common internal body representation underlying spatial perception of touch and nociception. The subject level differences suggest that in addition to these representations other aspects, possibly differences in primary representation and/or the influence of stimulus parameters, lead to differences in perceptual maps in individuals. PMID:23226126

Role of combined tactile and kinesthetic feedback in minimally invasive surgery.

PubMed

Lim, Soo-Chul; Lee, Hyung-Kew; Park, Joonah

2014-10-18

Haptic feedback is of critical importance in surgical tasks. However, conventional surgical robots do not provide haptic feedback to surgeons during surgery. Thus, in this study, a combined tactile and kinesthetic feedback system was developed to provide haptic feedback to surgeons during robotic surgery. To assess haptic feasibility, the effects of two types of haptic feedback were examined empirically - kinesthetic and tactile feedback - to measure object-pulling force with a telesurgery robotics system at two desired pulling forces (1 N and 2 N). Participants answered a set of questionnaires after experiments. The experimental results reveal reductions in force error (39.1% and 40.9%) when using haptic feedback during 1 N and 2 N pulling tasks. Moreover, survey analyses show the effectiveness of the haptic feedback during teleoperation. The combined tactile and kinesthetic feedback of the master device in robotic surgery improves the surgeon's ability to control the interaction force applied to the tissue. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Enhanced tactile encoding and memory recognition in congenital blindness.

PubMed

D'Angiulli, Amedeo; Waraich, Paul

2002-06-01

Several behavioural studies have shown that early-blind persons possess superior tactile skills. Since neurophysiological data show that early-blind persons recruit visual as well as somatosensory cortex to carry out tactile processing (cross-modal plasticity), blind persons' sharper tactile skills may be related to cortical re-organisation resulting from loss of vision early in their life. To examine the nature of blind individuals' tactile superiority and its implications for cross-modal plasticity, we compared the tactile performance of congenitally totally blind, low-vision and sighted children on raised-line picture identification test and re-test, assessing effects of task familiarity, exploratory strategy and memory recognition. What distinguished the blind from the other children was higher memory recognition and higher tactile encoding associated with efficient exploration. These results suggest that enhanced perceptual encoding and recognition memory may be two cognitive correlates of cross-modal plasticity in congenital blindness.

Exploring Tactile Perceptual Dimensions Using Materials Associated with Sensory Vocabulary.

PubMed

Sakamoto, Maki; Watanabe, Junji

2017-01-01

Considering tactile sensation when designing products is important because the decision to purchase often depends on how products feel. Numerous psychophysical studies have attempted to identify important factors that describe tactile perceptions. However, the numbers and types of major tactile dimensions reported in previous studies have varied because of differences in materials used across experiments. To obtain a more complete picture of perceptual space with regard to touch, our study focuses on using vocabulary that expresses tactile sensations as a guiding principle for collecting material samples because these types of words are expected to cover all the basic categories within tactile perceptual space. We collected 120 materials based on a variety of Japanese sound-symbolic words for tactile sensations, and used the materials to examine tactile perceptual dimensions and their associations with affective evaluations. Analysis revealed six major dimensions: "Affective evaluation and Friction," "Compliance," "Surface," "Volume," "Temperature," and "Naturalness." These dimensions include four factors that previous studies have regarded as fundamental, as well as two new factors: "Volume" and "Naturalness." Additionally, we showed that "Affective evaluation" is more closely related to the "Friction" component (slipperiness and dryness) than to other tactile perceptual features. Our study demonstrates that using vocabulary could be an effective method for selecting material samples to explore tactile perceptual space.

Synthetic tactile perception induced by transcranial alternating-current stimulation can substitute for natural sensory stimulus in behaving rabbits.

PubMed

Márquez-Ruiz, Javier; Ammann, Claudia; Leal-Campanario, Rocío; Ruffini, Giulio; Gruart, Agnès; Delgado-García, José M

2016-01-21

The use of brain-derived signals for controlling external devices has long attracted the attention from neuroscientists and engineers during last decades. Although much effort has been dedicated to establishing effective brain-to-computer communication, computer-to-brain communication feedback for "closing the loop" is now becoming a major research theme. While intracortical microstimulation of the sensory cortex has already been successfully used for this purpose, its future application in humans partly relies on the use of non-invasive brain stimulation technologies. In the present study, we explore the potential use of transcranial alternating-current stimulation (tACS) for synthetic tactile perception in alert behaving animals. More specifically, we determined the effects of tACS on sensory local field potentials (LFPs) and motor output and tested its capability for inducing tactile perception using classical eyeblink conditioning in the behaving animal. We demonstrated that tACS of the primary somatosensory cortex vibrissa area could indeed substitute natural stimuli during training in the associative learning paradigm.

Path integration in tactile perception of shapes.

PubMed

Moscatelli, Alessandro; Naceri, Abdeldjallil; Ernst, Marc O

2014-11-01

Whenever we move the hand across a surface, tactile signals provide information about the relative velocity between the skin and the surface. If the system were able to integrate the tactile velocity information over time, cutaneous touch may provide an estimate of the relative displacement between the hand and the surface. Here, we asked whether humans are able to form a reliable representation of the motion path from tactile cues only, integrating motion information over time. In order to address this issue, we conducted three experiments using tactile motion and asked participants (1) to estimate the length of a simulated triangle, (2) to reproduce the shape of a simulated triangular path, and (3) to estimate the angle between two-line segments. Participants were able to accurately indicate the length of the path, whereas the perceived direction was affected by a direction bias (inward bias). The response pattern was thus qualitatively similar to the ones reported in classical path integration studies involving locomotion. However, we explain the directional biases as the result of a tactile motion aftereffect. Copyright © 2014 Elsevier B.V. All rights reserved.

Planar and finger-shaped optical tactile sensors for robotic applications

NASA Technical Reports Server (NTRS)

Begej, Stefan

1988-01-01

Progress is described regarding the development of optical tactile sensors specifically designed for application to dexterous robotics. These sensors operate on optical principles involving the frustration of total internal reflection at a waveguide/elastomer interface and produce a grey-scale tactile image that represents the normal (vertical) forces of contact. The first tactile sensor discussed is a compact, 32 x 32 planar sensor array intended for mounting on a parallel-jaw gripper. Optical fibers were employed to convey the tactile image to a CCD camera and microprocessor-based image analysis system. The second sensor had the shape and size of a human fingertip and was designed for a dexterous robotic hand. It contained 256 sensing sites (taxels) distributed in a dual-density pattern that included a tactile fovea near the tip measuring 13 x 13 mm and containing 169 taxels. The design and construction details of these tactile sensors are presented, in addition to photographs of tactile imprints.

A tactile sensing element based on a hetero-core optical fiber for force measurement and texture detection

NASA Astrophysics Data System (ADS)

Yamazaki, Hiroshi; Koyama, Yuya; Watanabe, Kazuhiro

2014-05-01

Tactile sensing technology can measure a given property of an object through physical contact between a sensing element and the object. Various tactile sensing techniques have been developed for several applications such as intelligent robots, tactile interface, medical support and nursing care support. A desirable tactile sensing element for supporting human daily life can be embedded in the soft material with high sensitivity and accuracy in order to prevent from damaging to human or object physically. This report describes a new tactile sensing element. Hetero-core optical fibers have high sensitivity of macro-bending at local sensor portion and temperature independency, including advantages of optical fiber itself; thin size, light weight, flexible transmission line, and immunity to electro-magnetic interference. The proposed tactile sensing element could detect textures of touched objects through the optical loss caused by the force applied to the sensing element. The characteristics of the sensing element have been evaluated, in which the sensing element has the monotonic and non-linear sensitivity against the normal force ranged from 0 to 5 N with lower accuracy than 0.25 dB. Additionally, texture detection have been successfully demonstrated in which small surface figures of 0.1 mm in height were detected with spatial resolution of 0.4 mm.

Stretchable energy-harvesting tactile electronic skin capable of differentiating multiple mechanical stimuli modes.

PubMed

Park, Steve; Kim, Hyunjin; Vosgueritchian, Michael; Cheon, Sangmo; Kim, Hyeok; Koo, Ja Hoon; Kim, Taeho Roy; Lee, Sanghyo; Schwartz, Gregory; Chang, Hyuk; Bao, Zhenan

2014-11-19

The first stretchable energy-harvesting electronic-skin device capable of differentiating and generating energy from various mechanical stimuli, such as normal pressure, lateral strain, bending, and vibration, is presented. A pressure sensitivity of 0.7 kPa(-1) is achieved in the pressure region <1 kPa with power generation of tens of μW cm(-2) from a gentle finger touch. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Real-time edge tracking using a tactile sensor

NASA Technical Reports Server (NTRS)

Berger, Alan D.; Volpe, Richard; Khosla, Pradeep K.

1989-01-01

Object recognition through the use of input from multiple sensors is an important aspect of an autonomous manipulation system. In tactile object recognition, it is necessary to determine the location and orientation of object edges and surfaces. A controller is proposed that utilizes a tactile sensor in the feedback loop of a manipulator to track along edges. In the control system, the data from the tactile sensor is first processed to find edges. The parameters of these edges are then used to generate a control signal to a hybrid controller. Theory is presented for tactile edge detection and an edge tracking controller. In addition, experimental verification of the edge tracking controller is presented.

A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing

PubMed Central

Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W.F.; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B.-H.; Bao, Zhenan

2015-01-01

Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots. PMID:26300307

A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing.

PubMed

Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W F; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B-H; Bao, Zhenan

2015-08-24

Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots.

Integrated trimodal SSEP experimental setup for visual, auditory and tactile stimulation

NASA Astrophysics Data System (ADS)

Kuś, Rafał; Spustek, Tomasz; Zieleniewska, Magdalena; Duszyk, Anna; Rogowski, Piotr; Suffczyński, Piotr

2017-12-01

Objective. Steady-state evoked potentials (SSEPs), the brain responses to repetitive stimulation, are commonly used in both clinical practice and scientific research. Particular brain mechanisms underlying SSEPs in different modalities (i.e. visual, auditory and tactile) are very complex and still not completely understood. Each response has distinct resonant frequencies and exhibits a particular brain topography. Moreover, the topography can be frequency-dependent, as in case of auditory potentials. However, to study each modality separately and also to investigate multisensory interactions through multimodal experiments, a proper experimental setup appears to be of critical importance. The aim of this study was to design and evaluate a novel SSEP experimental setup providing a repetitive stimulation in three different modalities (visual, tactile and auditory) with a precise control of stimuli parameters. Results from a pilot study with a stimulation in a particular modality and in two modalities simultaneously prove the feasibility of the device to study SSEP phenomenon. Approach. We developed a setup of three separate stimulators that allows for a precise generation of repetitive stimuli. Besides sequential stimulation in a particular modality, parallel stimulation in up to three different modalities can be delivered. Stimulus in each modality is characterized by a stimulation frequency and a waveform (sine or square wave). We also present a novel methodology for the analysis of SSEPs. Main results. Apart from constructing the experimental setup, we conducted a pilot study with both sequential and simultaneous stimulation paradigms. EEG signals recorded during this study were analyzed with advanced methodology based on spatial filtering and adaptive approximation, followed by statistical evaluation. Significance. We developed a novel experimental setup for performing SSEP experiments. In this sense our study continues the ongoing research in this field. On the

The tactile motion aftereffect suggests an intensive code for speed in neurons sensitive to both speed and direction of motion

PubMed Central

Birznieks, I.; Vickery, R. M.; Holcombe, A. O.; Seizova-Cajic, T.

2016-01-01

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. PMID:26823511

Evaluation of somatosensory cortical differences between flutter and vibration tactile stimuli.

PubMed

Han, Sang Woo; Chung, Yoon Gi; Kim, Hyung-Sik; Chung, Soon-Cheol; Park, Jang-Yeon; Kim, Sung-Phil

2013-01-01

In parallel with advances in haptic-based mobile computing systems, understanding of the neural processing of vibrotactile information becomes of great importance. In the human nervous system, two types of vibrotactile information, flutter and vibration, are delivered from mechanoreceptors to the somatosensory cortex through segregated neural afferents. To investigate how the somatosensory cortex differentiates flutter and vibration, we analyzed the cortical responses to vibrotactile stimuli with a wide range of frequencies. Specifically, we examined whether cortical activity changed most around 50 Hz, which is known as a boundary between flutter and vibration. We explored various measures to evaluate separability of cortical activity across frequency and found that the hypothesis margin method resulted in the greatest separability between flutter and vibration. This result suggests that flutter and vibration information may be processed by different neural processes in the somatosensory cortex.

Cortical Local Field Potential Power Is Associated with Behavioral Detection of Near-threshold Stimuli in the Rat Whisker System: Dissociation between Orbitofrontal and Somatosensory Cortices.

PubMed

Rickard, Rachel E; Young, Andrew M J; Gerdjikov, Todor V

2018-01-01

There is growing evidence that ongoing brain oscillations may represent a key regulator of attentional processes and as such may contribute to behavioral performance in psychophysical tasks. OFC appears to be involved in the top-down modulation of sensory processing; however, the specific contribution of ongoing OFC oscillations to perception has not been characterized. Here we used the rat whiskers as a model system to further characterize the relationship between cortical state and tactile detection. Head-fixed rats were trained to report the presence of a vibrotactile stimulus (frequency = 60 Hz, duration = 2 sec, deflection amplitude = 0.01-0.5 mm) applied to a single vibrissa. We calculated power spectra of local field potentials preceding the onset of near-threshold stimuli from microelectrodes chronically implanted in OFC and somatosensory cortex. We found a dissociation between slow oscillation power in the two regions in relation to detection probability: Higher OFC but not somatosensory delta power was associated with increased detection probability. Furthermore, coherence between OFC and barrel cortex was reduced preceding successful detection. Consistent with the role of OFC in attention, our results identify a cortical network whose activity is differentially modulated before successful tactile detection.

Emergence of an abstract categorical code enabling the discrimination of temporally structured tactile stimuli

PubMed Central

Rossi-Pool, Román; Salinas, Emilio; Zainos, Antonio; Alvarez, Manuel; Vergara, José; Parga, Néstor; Romo, Ranulfo

2016-01-01

The problem of neural coding in perceptual decision making revolves around two fundamental questions: (i) How are the neural representations of sensory stimuli related to perception, and (ii) what attributes of these neural responses are relevant for downstream networks, and how do they influence decision making? We studied these two questions by recording neurons in primary somatosensory (S1) and dorsal premotor (DPC) cortex while trained monkeys reported whether the temporal pattern structure of two sequential vibrotactile stimuli (of equal mean frequency) was the same or different. We found that S1 neurons coded the temporal patterns in a literal way and only during the stimulation periods and did not reflect the monkeys’ decisions. In contrast, DPC neurons coded the stimulus patterns as broader categories and signaled them during the working memory, comparison, and decision periods. These results show that the initial sensory representation is transformed into an intermediate, more abstract categorical code that combines past and present information to ultimately generate a perceptually informed choice. PMID:27872293

Tactile stimulation during neonatal transition and its effect on vital parameters in neonates during neonatal transition.

PubMed

Baik-Schneditz, Nariae; Urlesberger, Berndt; Schwaberger, Bernhard; Mileder, Lukas; Schmölzer, Georg; Avian, Alexander; Pichler, Gerhard

2018-06-01

This study analysed tactile stimulation during neonatal transition and resuscitation in preterm and term neonates born by Caesarean delivery. It examined the frequency, location and body region, duration and possible effects of stimulation on heart rate and arterial oxygen saturation (SpO 2 ). Two independent investigators analysed video recordings of tactile stimulation on term and preterm neonates during neonatal transition from January 2012 to December 2014. They were recorded during a prospective observational study and randomised controlled trial at a tertiary centre, the Medical University of Graz, Austria. SpO 2 and heart rate were continuously recorded. Data on the frequency, body region and duration of stimulation were collected. To investigate the possible effects of stimulation, SpO 2 and heart rate were compared before and after stimulation. Term infants received tactile stimulation more than once, and it tended to start later, last longer and be applied in more locations than in preterm infants. Only preterm infants showed a significant increase in SpO 2 after stimulation and heart rates did not show any significant changes in either group. Tactile stimulation was applied in different ways to preterm and term infants during neonatal transition and SpO 2 showed a significant increase in preterm infants. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

The recalibration of tactile perception during tool use is body-part specific

PubMed Central

Cawley-Bennett, Andrew; Longo, Matthew R.; Saygin, Ayse P.

2018-01-01

Two decades of research have demonstrated that using a tool modulates spatial representations of the body. Whether this embodiment is specific to representations of the tool-using limb or extends to representations of other body parts has received little attention. Several studies of other perceptual phenomena have found that modulations to the primary somatosensory representation of the hand transfers to the face, due in part to their close proximity in primary somatosensory cortex. In the present study, we investigated whether tool-induced recalibration of tactile perception on the hand transfers to the cheek. Participants verbally estimated the distance between two tactile points applied to either their hand or face, before and after using a hand-shaped tool. Tool use recalibrated tactile distance perception on the hand—in line with previous findings—but left perception on the cheek unchanged. This finding provides support for the idea that embodiment is body-part specific. Furthermore, it suggests that tool-induced perceptual recalibration occurs at a level of somatosensory processing, where representations of the hand and face have become functionally disentangled. PMID:28702834

Vibratory tactile display for textures

NASA Technical Reports Server (NTRS)

Ikei, Yasushi; Ikeno, Akihisa; Fukuda, Shuichi

1994-01-01

We have developed a tactile display that produces vibratory stimulus to a fingertip in contact with a vibrating tactor matrix. The display depicts tactile surface textures while the user is exploring a virtual object surface. A piezoelectric actuator drives the individual tactor in accordance with both the finger movement and the surface texture being traced. Spatiotemporal display control schemes were examined for presenting the fundamental surface texture elements. The temporal duration of vibratory stimulus was experimentally optimized to simulate the adaptation process of cutaneous sensation. The selected duration time for presenting a single line edge agreed with the time threshold of tactile sensation. Then spatial stimulus disposition schemes were discussed for representation of other edge shapes. As an alternative means not relying on amplitude control, a method of augmented duration at the edge was investigated. Spatial resolution of the display was measured for the lines presented both in perpendicular and parallel to a finger axis. Discrimination of texture density was also measured on random dot textures.

Endoscopic vs. tactile evaluation of subgingival calculus.

PubMed

Osborn, Joy B; Lenton, Patricia A; Lunos, Scott A; Blue, Christine M

2014-08-01

Endoscopic technology has been developed to facilitate imagery for use during diagnostic and therapeutic phases of periodontal care. The purpose of this study was to compare the level of subgingival calculus detection using a periodontal endoscope with that of conventional tactile explorer in periodontitis subjects. A convenience sample of 26 subjects with moderate periodontitis in at least 2 quadrants was recruited from the University of Minnesota School of Dentistry to undergo quadrant scaling and root planing. One quadrant from each subject was randomized for tactile calculus detection alone and the other quadrant for tactile detection plus the Perioscope ™ (Perioscopy Inc., Oakland, Cali). A calculus index on a 0 to 3 score was performed at baseline and at 2 post-scaling and root planing visits. Sites where calculus was detected at visit 1 were retreated. T-tests were used to determine within-subject differences between Perioscope™ and tactile measures, and changes in measures between visits. Significantly more calculus was detected using the Perioscope™ vs. tactile explorer for all 3 subject visits (p<0.005). Mean changes (reduction) in calculus detection from baseline to visit 1 were statistically significant for both the Perioscope™ and tactile quadrants (p<0.0001). However, further reductions in calculus detection from visit 1 to visit 2 was only significant for the Perioscope™ quadrant (p<0.025), indicating that this methodology was able to more precisely detect calculus at this visit. It was concluded that the addition of a visual component to calculus detection via the Perioscope™ was most helpful in the re-evaluation phase of periodontal therapy. Copyright © 2014 The American Dental Hygienists’ Association.

Artificial tactile sensing in minimally invasive surgery - a new technical approach.

PubMed

Schostek, Sebastian; Ho, Chi-Nghia; Kalanovic, Daniel; Schurr, Marc O

2006-01-01

The loss of tactile sensation is a commonly known drawback of minimally invasive surgery (MIS). Since the advent of MIS, research activities in providing tactile information to the surgeon are still ongoing, in order to improve patient safety and to extend the indications for MIS. We have designed a tactile sensor system comprising a tactile laparoscopic grasper for surgical palpation. For this purpose, we developed a novel tactile sensor technology which allows the manufacturing of an integrated sensor array within an acceptable price range. The array was integrated into the jaws of a 10mm laparoscopic grasper. The tactile data are transferred wirelessly via Bluetooth and are presented visually to the surgeon. The goal was to be able to obtain information about the shape and consistency of tissue structures by gently compressing the tissue between the jaws of the tactile instrument and thus to be able to recognize and assess anatomical or pathological structures, even if they are hidden in the tissue. With a prototype of the tactile sensor system we have conducted bench-tests as well as in-vitro and in-vivo experiments. The system proved feasibility in an experimental environment, it was easy to use, and the novel tactile sensor array was applicable for both palpation and grasping manoeuvres with forces of up to 60N. The tactile data turned out to be a useful supplement to the minimal amount of haptic feedback that is provided by current endoscopic instruments and the endoscopic image under certain conditions.

Microfabricated Tactile Sensors for Biomedical Applications: A Review

PubMed Central

Saccomandi, Paola; Schena, Emiliano; Oddo, Calogero Maria; Zollo, Loredana; Silvestri, Sergio; Guglielmelli, Eugenio

2014-01-01

During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described. PMID:25587432

Microfabricated tactile sensors for biomedical applications: a review.

PubMed

Saccomandi, Paola; Schena, Emiliano; Oddo, Calogero Maria; Zollo, Loredana; Silvestri, Sergio; Guglielmelli, Eugenio

2014-12-01

During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described.

Review of Recent Inkjet-Printed Capacitive Tactile Sensors

PubMed Central

Salim, Ahmed

2017-01-01

Inkjet printing is an advanced printing technology that has been used to develop conducting layers, interconnects and other features on a variety of substrates. It is an additive manufacturing process that offers cost-effective, lightweight designs and simplifies the fabrication process with little effort. There is hardly sufficient research on tactile sensors and inkjet printing. Advancements in materials science and inkjet printing greatly facilitate the realization of sophisticated tactile sensors. Starting from the concept of capacitive sensing, a brief comparison of printing techniques, the essential requirements of inkjet-printing and the attractive features of state-of-the art inkjet-printed tactile sensors developed on diverse substrates (paper, polymer, glass and textile) are presented in this comprehensive review. Recent trends in inkjet-printed wearable/flexible and foldable tactile sensors are evaluated, paving the way for future research. PMID:29125584

Slip detection with accelerometer and tactile sensors in a robotic hand model

NASA Astrophysics Data System (ADS)

Al-Shanoon, Abdulrahman Abdulkareem S.; Anom Ahmad, Siti; Hassan, Mohd. Khair b.

2015-11-01

Grasp planning is an interesting issue in studies that dedicated efforts to investigate tactile sensors. This study investigated the physical force interaction between a tactile pressure sensor and a particular object. It also characterized object slipping during gripping operations and presented secure regripping of an object. Acceleration force was analyzed using an accelerometer sensor to establish a completely autonomous robotic hand model. An automatic feedback control system was applied to regrip the particular object when it commences to slip. Empirical findings were presented in consideration of the detection and subsequent control of the slippage situation. These findings revealed the correlation between the distance of the object slipping and the required force to regrip the object safely. This approach is similar to Hooke's law formula.

Tactile interaction with taste localization: influence of gustatory quality and intensity.

PubMed

Lim, Juyun; Green, Barry G

2008-02-01

Taste is always accompanied by tactile stimulation, but little is known about how touch interacts with taste. One exception is evidence that taste can be "referred" to nearby tactile stimulation. It was recently found (Lim J, and Green BG. 2007. The psychophysical relationship between bitter taste and burning sensation: evidence of qualitative similarity. Chem Senses. 32:31-39) that spatial discrimination of taste was poorer for bitterness than for other tastes when the perceived intensities were matched. We hypothesized that this difference may have been caused by greater referral of bitterness by touch. The present study tested this hypothesis by comparing localization of quinine sulfate and sucrose under conditions that minimized and maximized the opportunity for referral. In both conditions, stimulation was produced by 5 cotton swabs spaced 1 cm apart and arranged in an arc to enable simultaneous contact with the front edge of the tongue. Only one swab contained the taste stimulus, whereas the rest were saturated with deionized water. In both conditions, the swabs were stroked up-and-down against the tongue 5 times. Subjects were asked to identify which swab contained the taste stimulus 1) 5 s after the fifth stroke (touch-removed condition) and 2) immediately at the end of the fifth stroke, with the swabs still in contact with the tongue (touch-maintained condition). Ratings of taste intensity were obtained to assess the possible effect of perceived intensity on spatial localization. Taste localization was surprisingly accurate, especially for sucrose, with errors of localization in the range of 1 cm or less. For both stimuli, localization tended to be poorer when the tactile stimulus was present while subjects made their judgments, but the difference between conditions was significant only for the lower concentration of quinine. The results are discussed in terms of both the surprisingly good spatial acuity of taste and the possibility of having a close

Detection of hydrodynamic stimuli by the postcranial body of Florida manatees (Trichechus manatus latirostris).

PubMed

Gaspard, Joseph C; Bauer, Gordon B; Mann, David A; Boerner, Katharine; Denum, Laura; Frances, Candice; Reep, Roger L

2017-02-01

Manatees live in shallow, frequently turbid waters. The sensory means by which they navigate in these conditions are unknown. Poor visual acuity, lack of echolocation, and modest chemosensation suggest that other modalities play an important role. Rich innervation of sensory hairs that cover the entire body and enlarged somatosensory areas of the brain suggest that tactile senses are good candidates. Previous tests of detection of underwater vibratory stimuli indicated that they use passive movement of the hairs to detect particle displacements in the vicinity of a micron or less for frequencies from 10 to 150 Hz. In the current study, hydrodynamic stimuli were created by a sinusoidally oscillating sphere that generated a dipole field at frequencies from 5 to 150 Hz. Go/no-go tests of manatee postcranial mechanoreception of hydrodynamic stimuli indicated excellent sensitivity but about an order of magnitude less than the facial region. When the vibrissae were trimmed, detection thresholds were elevated, suggesting that the vibrissae were an important means by which detection occurred. Manatees were also highly accurate in two-choice directional discrimination: greater than 90% correct at all frequencies tested. We hypothesize that manatees utilize vibrissae as a three-dimensional array to detect and localize low-frequency hydrodynamic stimuli.

The magnetic touch illusion: A perceptual correlate of visuo-tactile integration in peripersonal space.

PubMed

Guterstam, Arvid; Zeberg, Hugo; Özçiftci, Vedat Menderes; Ehrsson, H Henrik

2016-10-01

To accurately localize our limbs and guide movements toward external objects, the brain must represent the body and its surrounding (peripersonal) visual space. Specific multisensory neurons encode peripersonal space in the monkey brain, and neurobehavioral studies have suggested the existence of a similar representation in humans. However, because peripersonal space lacks a distinct perceptual correlate, its involvement in spatial and bodily perception remains unclear. Here, we show that applying brushstrokes in mid-air at some distance above a rubber hand-without touching it-in synchrony with brushstrokes applied to a participant's hidden real hand results in the illusory sensation of a "magnetic force" between the brush and the rubber hand, which strongly correlates with the perception of the rubber hand as one's own. In eight experiments, we characterized this "magnetic touch illusion" by using quantitative subjective reports, motion tracking, and behavioral data consisting of pointing errors toward the rubber hand in an intermanual pointing task. We found that the illusion depends on visuo-tactile synchrony and exhibits similarities with the visuo-tactile receptive field properties of peripersonal space neurons, featuring a non-linear decay at 40cm that is independent of gaze direction and follows changes in the rubber hand position. Moreover, the "magnetic force" does not penetrate physical barriers, thus further linking this phenomenon to body-specific visuo-tactile integration processes. These findings provide strong support for the notion that multisensory integration within peripersonal space underlies bodily self-attribution. Furthermore, we propose that the magnetic touch illusion constitutes a perceptual correlate of visuo-tactile integration in peripersonal space. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

Design Optimisation of a Magnetic Field Based Soft Tactile Sensor

PubMed Central

Raske, Nicholas; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Culmer, Peter; Hewson, Robert

2017-01-01

This paper investigates the design optimisation of a magnetic field based soft tactile sensor, comprised of a magnet and Hall effect module separated by an elastomer. The aim was to minimise sensitivity of the output force with respect to the input magnetic field; this was achieved by varying the geometry and material properties. Finite element simulations determined the magnetic field and structural behaviour under load. Genetic programming produced phenomenological expressions describing these responses. Optimisation studies constrained by a measurable force and stable loading conditions were conducted; these produced Pareto sets of designs from which the optimal sensor characteristics were selected. The optimisation demonstrated a compromise between sensitivity and the measurable force, a fabricated version of the optimised sensor validated the improvements made using this methodology. The approach presented can be applied in general for optimising soft tactile sensor designs over a range of applications and sensing modes. PMID:29099787

Evaluation of the MEMS based portable respiratory training system with a tactile sensor for respiratory-gated radiotherapy

NASA Astrophysics Data System (ADS)

Moon, Sun Young; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

2017-10-01

In respiratory-gated radiotherapy, it is important to maintain the regular respiratory cycles of patients. If patients undergo respiration training, their regular breathing pattern is affected. Therefore, we developed a respiratory training system based on a micro electromechanical system (MEMS) and evaluated the feasibility of the MEMS in radiotherapy. By comparing the measured signal before and after radiation exposure, we confirmed the effects of radiation. By evaluating the period of the electric signal emitted by a tactile sensor and its constancy, the performance of the tactile sensor was confirmed. Moreover, by comparing the delay between the motion of the MEMS and the electric signal from the tactile sensor, we confirmed the reaction time of the tactile sensor. The results showed that a baseline shift occurred for an accumulated dose of 400 Gy in the sensor, and both the amplitude and period changed. The period of the signal released by the tactile sensor was 5.39 and its standard deviation was 0.06. Considering the errors from the motion phantom, a standard deviation of 0.06 was desirable. The delay time was within 0.5 s and not distinguishable by a patient. We confirmed the performance of the MEMS and concluded that MEMS could be applied to patients for respiratory-gated radiotherapy.

MEMS tactile display: from fabrication to characterization

NASA Astrophysics Data System (ADS)

Miki, Norihisa; Kosemura, Yumi; Watanabe, Junpei; Ishikawa, Hiroaki

2014-03-01

We report fabrication and characterization of MEMS-based tactile display that can display users various tactile information, such as Braille codes and surface textures. The display consists of 9 micro-actuators that are equipped with hydraulic displacement amplification mechanism (HDAM) to achieve large enough displacement to stimulate the human tactile receptors. HDAM encapsulates incompressible liquids. We developed a liquid encapsulation process, which we termed as Bonding-in-Liquid Technique, where bonding with a UV-curable resin in glycerin is conducted in the liquid, which prevented interfusion of air bubbles and deformation of the membrane during the bonding. HDAM successfully amplified the displacement generated by piezoelectric actuators by a factor of 6. The display could virtually produce "rough" and "smooth" surfaces, by controlling the vibration frequency, displacement, and the actuation periods of an actuator until the adjacent actuator was driven. We introduced a sample comparison method to characterize the surfaces, which involves human tactile sensation. First, we prepared samples whose mechanical properties are known. We displayed a surface texture to the user by controlling the parameters and then, the user selects a sample that has the most similar surface texture. By doing so, we can correlate the parameters with the mechanical properties of the sample as well as find the sets of the parameters that can provide similar tactile information to many users. The preliminary results with respect to roughness and hardness is presented.

Does bimodal stimulus presentation increase ERP components usable in BCIs?

NASA Astrophysics Data System (ADS)

Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Blankertz, Benjamin; Werkhoven, Peter J.

2012-08-01

Event-related potential (ERP)-based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain activity due to multisensory integration which may be of use in BCIs. We investigated the effect of visual-tactile stimulus presentation on the chain of ERP components, BCI performance (classification accuracies and bitrates) and participants’ task performance (counting of targets). Ten participants were instructed to navigate a visual display by attending (spatially) to targets in sequences of either visual, tactile or visual-tactile stimuli. We observe that attending to visual-tactile (compared to either visual or tactile) stimuli results in an enhanced early ERP component (N1). This bimodal N1 may enhance BCI performance, as suggested by a nonsignificant positive trend in offline classification accuracies. A late ERP component (P300) is reduced when attending to visual-tactile compared to visual stimuli, which is consistent with the nonsignificant negative trend of participants’ task performance. We discuss these findings in the light of affected spatial attention at high-level compared to low-level stimulus processing. Furthermore, we evaluate bimodal BCIs from a practical perspective and for future applications.

A Single Session of Mirror-based Tactile and Motor Training Improves Tactile Dysfunction in Children with Unilateral Cerebral Palsy: A Replicated Randomized Controlled Case Series.

PubMed

Auld, Megan L; Johnston, Leanne M; Russo, Remo N; Moseley, G Lorimer

2017-10-01

This replicated randomized controlled crossover case series investigated the effect of mirror-based tactile and motor training on tactile registration and perception in children with unilateral cerebral palsy (UCP). Six children with UCP (6-18 years; median 10 years, five male, three-left hemiplegia, four-manual ability classification system (MACS) I, one MACS II and one MACS III) participated. They attended two 90-minute sessions - one of mirror-based training and one of standard practice, bimanual therapy - in alternated order. Tactile registration (Semmes Weinstein Monofilaments) and perception (double simultaneous or single-point localization) were assessed before and after each session. Change was estimated using reliable change index (RCI). Tactile perception improved in four participants (RCI > 1.75), with mirror-based training, but was unchanged with bimanual therapy (RCI < 1.0 for all participants). Neither intervention affected tactile registration. Mirror-based training demonstrates potential to improve tactile perception in children with UCP. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Using computer simulations to determine the limitations of dynamic clamp stimuli applied at the soma in mimicking distributed conductance sources.

PubMed

Lin, Risa J; Jaeger, Dieter

2011-05-01

In previous studies we used the technique of dynamic clamp to study how temporal modulation of inhibitory and excitatory inputs control the frequency and precise timing of spikes in neurons of the deep cerebellar nuclei (DCN). Although this technique is now widely used, it is limited to interpreting conductance inputs as being location independent; i.e., all inputs that are biologically distributed across the dendritic tree are applied to the soma. We used computer simulations of a morphologically realistic model of DCN neurons to compare the effects of purely somatic vs. distributed dendritic inputs in this cell type. We applied the same conductance stimuli used in our published experiments to the model. To simulate variability in neuronal responses to repeated stimuli, we added a somatic white current noise to reproduce subthreshold fluctuations in the membrane potential. We were able to replicate our dynamic clamp results with respect to spike rates and spike precision for different patterns of background synaptic activity. We found only minor differences in the spike pattern generation between focal or distributed input in this cell type even when strong inhibitory or excitatory bursts were applied. However, the location dependence of dynamic clamp stimuli is likely to be different for each cell type examined, and the simulation approach developed in the present study will allow a careful assessment of location dependence in all cell types.

Tactile Data Entry System

NASA Technical Reports Server (NTRS)

Adams, Richard J.

2015-01-01

The patent-pending Glove-Enabled Computer Operations (GECO) design leverages extravehicular activity (EVA) glove design features as platforms for instrumentation and tactile feedback, enabling the gloves to function as human-computer interface devices. Flexible sensors in each finger enable control inputs that can be mapped to any number of functions (e.g., a mouse click, a keyboard strike, or a button press). Tracking of hand motion is interpreted alternatively as movement of a mouse (change in cursor position on a graphical user interface) or a change in hand position on a virtual keyboard. Programmable vibro-tactile actuators aligned with each finger enrich the interface by creating the haptic sensations associated with control inputs, such as recoil of a button press.

Tactile texture and friction of soft sponge surfaces.

PubMed

Takahashi, Akira; Suzuki, Makoto; Imai, Yumi; Nonomura, Yoshimune

2015-06-01

We evaluated the tactile texture and frictional properties of five soft sponges with various cell sizes. The frictional forces were measured by a friction meter containing a contact probe with human-finger-like geometry and mechanical properties. When the subjects touched these sponges with their fingers, hard-textured sponges were deemed unpleasant. This tactile feeling changed with friction factors including friction coefficients, their temporal patterns, as well as mechanical and shape factors. These findings provide useful information on how to control the tactile textures of various sponges. Copyright © 2015 Elsevier B.V. All rights reserved.

A flexible dual mode tactile and proximity sensor using carbon microcoils

NASA Astrophysics Data System (ADS)

Han, Hyo Seung; Park, Junwoo; Nguyen, Tien Dat; Kim, Uikyum; Jeong, Soon Cheol; Kang, Doo In; Choi, Hyouk Ryeol

2016-04-01

This paper proposes a flexible dual mode tactile and proximity sensor using Carbon Microcoils (CMCs). The sensor consists of a Flexible Printed Circuit Board (FPCB) electrode layer and a dielectric layer of CMCs composite. In order to avoid damage from frequent contacts, the sensor has all electrodes on the same plane and a polymer covering is placed on the top of the sensor. CMCs can be modeled as complex LCR circuit and the sensitivity of the sensor highly depends on the CMC content. Proper CMC content is experimentally investigated and applied to make the CMCs composite for the dielectric layer. The CMC sensor measures the capacitance for tactile stimulus and inductance for proximity stimulus. A prototype with a size of 30 × 30 × 0.6 𝑚𝑚3, is manufactured and its feasibility is experimentally validated.

Effective learning and retention of braille letter tactile discrimination skills in children with developmental dyslexia.

PubMed

Hayek, Maisam; Dorfberger, Shoshi; Karni, Avi

2016-01-01

Children with developmental dyslexia (DD) may differ from typical readers in aspects other than reading. The notion of a general deficit in the ability to acquire and retain procedural ('how to') knowledge as long-term procedural memory has been proposed. Here, we compared the ability of elementary school children, with and without reading difficulties (DD, typical readers), to improve their tactile discrimination with practice and tested the children's ability to retain the gains. Forty 10-11-year-olds practiced the tactile discrimination of four braille letters, presented as pairs, while blindfolded. In a trial, participants were asked to report whether the target stimuli were identical or different from each other. The structured training session consisted of six blocks of 16 trials each. Performance was re-tested at 24 hours and two weeks post-training. Both groups improved in speed and in accuracy. In session 1, children with DD started as significantly less accurate and were slower than the typical readers but showed rapid learning and successfully closed the gap. Only two children with DD failed to benefit from training and were not included in subsequent data analyses. At 24 hours post-training both groups showed effective retention of the gains in speed and accuracy. Importantly, children with DD were able to retain the gains in speed and accuracy, over a two-week interval as effectively as typical readers. Thus, children with DD were as effective in the acquisition and retention of tactile discrimination of braille letters as typical readers of the same age. The results do not support the notion of a general procedural learning disability in DD. © 2015 John Wiley & Sons Ltd.

Detection of hydrodynamic stimuli by the Florida manatee (Trichechus manatus latirostris).

PubMed

Gaspard, Joseph C; Bauer, Gordon B; Reep, Roger L; Dziuk, Kimberly; Read, Latoshia; Mann, David A

2013-06-01

Florida manatees inhabit the coastal and inland waters of the peninsular state. They have little difficulty navigating the turbid waterways, which often contain obstacles that they must circumnavigate. Anatomical and behavioral research suggests that the vibrissae and associated follicle-sinus complexes that manatees possess over their entire body form a sensory array system for detecting hydrodynamic stimuli analogous to the lateral line system of fish. This is consistent with data highlighting that manatees are tactile specialists, evidenced by their specialized facial morphology and use of their vibrissae during feeding and active investigation/manipulation of objects. Two Florida manatees were tested in a go/no-go procedure using a staircase method to assess their ability to detect low-frequency water movement. Hydrodynamic vibrations were created by a sinusoidally oscillating sphere that generated a dipole field at frequencies from 5 to 150 Hz, which are below the apparent functional hearing limit of the manatee. The manatees detected particle displacement of less than 1 μm for frequencies of 15-150 Hz and of less than a nanometer at 150 Hz. Restricting the facial vibrissae with various size mesh openings indicated that the specialized sensory hairs played an important role in the manatee's exquisite tactile sensitivity.

Graphical tactile displays for visually-impaired people.

PubMed

Vidal-Verdú, Fernando; Hafez, Moustapha

2007-03-01

This paper presents an up-to-date survey of graphical tactile displays. These devices provide information through the sense of touch. At best, they should display both text and graphics (text may be considered a type of graphic). Graphs made with shapeable sheets result in bulky items awkward to store and transport; their production is expensive and time-consuming and they deteriorate quickly. Research is ongoing for a refreshable tactile display that acts as an output device for a computer or other information source and can present the information in text and graphics. The work in this field has branched into diverse areas, from physiological studies to technological aspects and challenges. Moreover, interest in these devices is now being shown by other fields such as virtual reality, minimally invasive surgery and teleoperation. It is attracting more and more people, research and money. Many proposals have been put forward, several of them succeeding in the task of presenting tactile information. However, most are research prototypes and very expensive to produce commercially. Thus the goal of an efficient low-cost tactile display for visually-impaired people has not yet been reached.

RETENTION OF HIGH TACTILE ACUITY THROUGHOUT THE LIFESPAN IN BLINDNESS

PubMed Central

Legge, Gordon E.; Madison, Cindee; Vaughn, Brenna N.; Cheong, Allen M.Y.; Miller, Joseph C.

2009-01-01

Previous studies of tactile acuity on the fingertip using passive touch have demonstrated an age-related decline in spatial resolution for both sighted and blind subjects. We have re-examined this age dependence with two newly designed tactile-acuity charts requiring active exploration of the test symbols. One chart used dot patterns similar to Braille and the other used embossed Landolt rings. Groups of blind Braille readers and sighted subjects, ranging in age from 12 to 85 years, were tested in two experiments. We replicated previous findings for sighted subjects by showing an age related decrease in tactile acuity by nearly 1% per year. Surprisingly, the blind subjects retained high acuity into old age showing no age-related decline. For the blind subjects, tactile acuity did not correlate with braille reading speed, the amount of daily reading, or the age at which braille was learned. We conclude that when measured with active touch, blind subjects retain high tactile acuity into old age, unlike their aging sighted peers. We propose that blind people's use of active touch in daily activities, not specifically Braille reading, results in preservation of tactile acuity across the lifespan. PMID:19064491

Blindness enhances tactile acuity and haptic 3-D shape discrimination.

PubMed

Norman, J Farley; Bartholomew, Ashley N

2011-10-01

This study compared the sensory and perceptual abilities of the blind and sighted. The 32 participants were required to perform two tasks: tactile grating orientation discrimination (to determine tactile acuity) and haptic three-dimensional (3-D) shape discrimination. The results indicated that the blind outperformed their sighted counterparts (individually matched for both age and sex) on both tactile tasks. The improvements in tactile acuity that accompanied blindness occurred for all blind groups (congenital, early, and late). However, the improvements in haptic 3-D shape discrimination only occurred for the early-onset and late-onset blindness groups; the performance of the congenitally blind was no better than that of the sighted controls. The results of the present study demonstrate that blindness does lead to an enhancement of tactile abilities, but they also suggest that early visual experience may play a role in facilitating haptic 3-D shape discrimination.

Temporal order and processing acuity of visual, auditory, and tactile perception in developmentally dyslexic young adults.

PubMed

Laasonen, M; Service, E; Virsu, V

2001-12-01

We studied the temporal acuity of 16 developmentally dyslexic young adults in three perceptual modalities. The control group consisted of 16 age- and IQ-matched normal readers. Two methods were used. In the temporal order judgment (TOJ) method, the stimuli were spatially separate fingertip indentations in the tactile system, tone bursts of different pitches in audition, and light flashes in vision. Participants indicated which one of two stimuli appeared first. To test temporal processing acuity (TPA), the same 8-msec nonspeech stimuli were presented as two parallel sequences of three stimulus pulses. Participants indicated, without order judgments, whether the pulses of the two sequences were simultaneous or nonsimultaneous. The dyslexic readers were somewhat inferior to the normal readers in all six temporal acuity tasks on average. Thus, our results agreed with the existence of a pansensory temporal processing deficit associated with dyslexia in a language with shallow orthography (Finnish) and in well-educated adults. The dyslexic and normal readers' temporal acuities overlapped so much, however, that acuity deficits alone would not allow dyslexia diagnoses. It was irrelevant whether or not the acuity task required order judgments. The groups did not differ in the nontemporal aspects of our experiments. Correlations between temporal acuity and reading-related tasks suggested that temporal acuity is associated with phonological awareness.

A Finger-Shaped Tactile Sensor for Fabric Surfaces Evaluation by 2-Dimensional Active Sliding Touch

PubMed Central

Hu, Haihua; Han, Yezhen; Song, Aiguo; Chen, Shanguang; Wang, Chunhui; Wang, Zheng

2014-01-01

Sliding tactile perception is a basic function for human beings to determine the mechanical properties of object surfaces and recognize materials. Imitating this process, this paper proposes a novel finger-shaped tactile sensor based on a thin piezoelectric polyvinylidene fluoride (PVDF) film for surface texture measurement. A parallelogram mechanism is designed to ensure that the sensor applies a constant contact force perpendicular to the object surface, and a 2-dimensional movable mechanical structure is utilized to generate the relative motion at a certain speed between the sensor and the object surface. By controlling the 2-dimensional motion of the finger-shaped sensor along the object surface, small height/depth variation of surface texture changes the output charge of PVDF film then surface texture can be measured. In this paper, the finger-shaped tactile sensor is used to evaluate and classify five different kinds of linen. Fast Fourier Transformation (FFT) is utilized to get original attribute data of surface in the frequency domain, and principal component analysis (PCA) is used to compress the attribute data and extract feature information. Finally, low dimensional features are classified by Support Vector Machine (SVM). The experimental results show that this finger-shaped tactile sensor is effective and high accurate for discriminating the five textures. PMID:24618775

A Novel Tactile Sensor with Electromagnetic Induction and Its Application on Stick-Slip Interaction Detection

PubMed Central

Liu, Yanjie; Han, Haijun; Liu, Tao; Yi, Jingang; Li, Qingguo; Inoue, Yoshio

2016-01-01

Real-time detection of contact states, such as stick-slip interaction between a robot and an object on its end effector, is crucial for the robot to grasp and manipulate the object steadily. This paper presents a novel tactile sensor based on electromagnetic induction and its application on stick-slip interaction. An equivalent cantilever-beam model of the tactile sensor was built and capable of constructing the relationship between the sensor output and the friction applied on the sensor. With the tactile sensor, a new method to detect stick-slip interaction on the contact surface between the object and the sensor is proposed based on the characteristics of friction change. Furthermore, a prototype was developed for a typical application, stable wafer transferring on a wafer transfer robot, by considering the spatial magnetic field distribution and the sensor size according to the requirements of wafer transfer. The experimental results validate the sensing mechanism of the tactile sensor and verify its feasibility of detecting stick-slip on the contact surface between the wafer and the sensor. The sensing mechanism also provides a new approach to detect the contact state on the soft-rigid surface in other robot-environment interaction systems. PMID:27023545

A finger-shaped tactile sensor for fabric surfaces evaluation by 2-dimensional active sliding touch.

PubMed

Hu, Haihua; Han, Yezhen; Song, Aiguo; Chen, Shanguang; Wang, Chunhui; Wang, Zheng

2014-03-11

Sliding tactile perception is a basic function for human beings to determine the mechanical properties of object surfaces and recognize materials. Imitating this process, this paper proposes a novel finger-shaped tactile sensor based on a thin piezoelectric polyvinylidene fluoride (PVDF) film for surface texture measurement. A parallelogram mechanism is designed to ensure that the sensor applies a constant contact force perpendicular to the object surface, and a 2-dimensional movable mechanical structure is utilized to generate the relative motion at a certain speed between the sensor and the object surface. By controlling the 2-dimensional motion of the finger-shaped sensor along the object surface, small height/depth variation of surface texture changes the output charge of PVDF film then surface texture can be measured. In this paper, the finger-shaped tactile sensor is used to evaluate and classify five different kinds of linen. Fast Fourier Transformation (FFT) is utilized to get original attribute data of surface in the frequency domain, and principal component analysis (PCA) is used to compress the attribute data and extract feature information. Finally, low dimensional features are classified by Support Vector Machine (SVM). The experimental results show that this finger-shaped tactile sensor is effective and high accurate for discriminating the five textures.

Extrafoveally applied flashing light affects contrast thresholds of achromatic and S-cone isolating, but not L-M cone modulated stimuli.

PubMed

Őze, A; Puszta, A; Buzás, P; Kóbor, P; Braunitzer, G; Nagy, A

2018-06-21

Flashing light stimulation is often used to investigate the visual system. However, the magnitude of the effect of this stimulus on the various subcortical pathways is not well investigated. The signals of conscious vision are conveyed by the magnocellular, parvocellular and koniocellular pathways. Parvocellular and koniocellular pathways (or more precisely, the L-M opponent and S-cone isolating channels) can be accessed by isoluminant red-green (L-M) and S-cone isolating stimuli, respectively. The main goal of the present study was to explore how costimulation with strong white extrafoveal light flashes alters the perception of stimuli specific to these pathways. Eleven healthy volunteers with negative neurological and ophthalmological history were enrolled for the study. Isoluminance of L-M and S-cone isolating sine-wave gratings was set individually, using the minimum motion procedure. The contrast thresholds for these stimuli as well as for achromatic gratings were determined by an adaptive staircase procedure where subjects had to indicate the orientation (horizontal, oblique or vertical) of the gratings. Thresholds were then determined again while a strong white peripheral light flash was presented 50 ms before each trial. Peripheral light flashes significantly (p < 0.05) increased the contrast thresholds of the achromatic and S-cone isolating stimuli. The threshold elevation was especially marked in case of the achromatic stimuli. However, the contrast threshold for the L-M stimuli was not significantly influenced by the light flashes. We conclude that extrafoveally applied light flashes influence predominantly the perception of achromatic stimuli. Copyright © 2018 Elsevier B.V. All rights reserved.

Numbness in clinical and experimental pain--a cross-sectional study exploring the mechanisms of reduced tactile function.

PubMed

Geber, Christian; Magerl, Walter; Fondel, Ricarda; Fechir, Marcel; Rolke, Roman; Vogt, Thomas; Treede, Rolf-Detlef; Birklein, Frank

2008-09-30

Pain patients often report distinct numbness of the painful skin although no structural peripheral or central nerve lesion is obvious. In this cross-sectional study we assessed the reduction of tactile function and studied underlying mechanisms in patients with chronic pain and in healthy participants exposed to phasic and tonic experimental nociceptive stimulation. Mechanical detection (MDT) and pain thresholds (MPT) were assessed in the painful area and the non-painful contralateral side in 10 patients with unilateral musculoskeletal pain. Additionally, 10 healthy participants were exposed to nociceptive stimulation applied to the volar forearms (capsaicin; electrical stimulation, twice each). Areas of tactile hypaesthesia and mechanical hyperalgesia were assessed. MDT and MPT were quantified adjacent to the stimulation site. Tactile hypaesthesia in pain patients and in experimental pain (MDT-z-scores: -0.66+/-0.30 and -0.42+/-0.15, respectively, both p<0.01) was paralleled by mechanical hyperalgesia (MPT-z-scores: +0.51+/-0.27, p<0.05; and +0.48+/-0.10, p<0.001). However, hypaesthesia and hyperalgesia were not correlated. Although 9 patients reported numbness, only 3 of them were able to delineate circumscript areas of tactile hypaesthesia. In experimental pain, the area of tactile hypaesthesia could be mapped in 31/40 experiments (78%). Irrespective of the mode of nociceptive stimulation (phasic vs. tonic) tactile hypaesthesia and hyperalgesia developed with a similar time course and disappeared within approximately 1 day. Hypaesthesia (numbness) often encountered in clinical pain can be reproduced by experimental nociceptive stimulation. The time course of effects suggests a mechanism involving central plasticity.

Synthetic and Bio-Artificial Tactile Sensing: A Review

PubMed Central

Lucarotti, Chiara; Oddo, Calogero Maria; Vitiello, Nicola; Carrozza, Maria Chiara

2013-01-01

This paper reviews the state of the art of artificial tactile sensing, with a particular focus on bio-hybrid and fully-biological approaches. To this aim, the study of physiology of the human sense of touch and of the coding mechanisms of tactile information is a significant starting point, which is briefly explored in this review. Then, the progress towards the development of an artificial sense of touch are investigated. Artificial tactile sensing is analysed with respect to the possible approaches to fabricate the outer interface layer: synthetic skin versus bio-artificial skin. With particular respect to the synthetic skin approach, a brief overview is provided on various technologies and transduction principles that can be integrated beneath the skin layer. Then, the main focus moves to approaches characterized by the use of bio-artificial skin as an outer layer of the artificial sensory system. Within this design solution for the skin, bio-hybrid and fully-biological tactile sensing systems are thoroughly presented: while significant results have been reported for the development of tissue engineered skins, the development of mechanotransduction units and their integration is a recent trend that is still lagging behind, therefore requiring research efforts and investments. In the last part of the paper, application domains and perspectives of the reviewed tactile sensing technologies are discussed. PMID:23348032

Comparison of measurement methods for capacitive tactile sensors and their implementation

NASA Astrophysics Data System (ADS)

Tarapata, Grzegorz; Sienkiewicz, Rafał

2015-09-01

This paper presents a review of ideas and implementations of measurement methods utilized for capacity measurements in tactile sensors. The paper describes technical method, charge amplification method, generation and as well integration method. Three selected methods were implemented in dedicated measurement system and utilised for capacitance measurements of ourselves made tactile sensors. The tactile sensors tested in this work were fully fabricated with the inkjet printing technology. The tests result were presented and summarised. The charge amplification method (CDC) was selected as the best method for the measurement of the tactile sensors.

Audio-tactile integration and the influence of musical training.

PubMed

Kuchenbuch, Anja; Paraskevopoulos, Evangelos; Herholz, Sibylle C; Pantev, Christo

2014-01-01

Perception of our environment is a multisensory experience; information from different sensory systems like the auditory, visual and tactile is constantly integrated. Complex tasks that require high temporal and spatial precision of multisensory integration put strong demands on the underlying networks but it is largely unknown how task experience shapes multisensory processing. Long-term musical training is an excellent model for brain plasticity because it shapes the human brain at functional and structural levels, affecting a network of brain areas. In the present study we used magnetoencephalography (MEG) to investigate how audio-tactile perception is integrated in the human brain and if musicians show enhancement of the corresponding activation compared to non-musicians. Using a paradigm that allowed the investigation of combined and separate auditory and tactile processing, we found a multisensory incongruency response, generated in frontal, cingulate and cerebellar regions, an auditory mismatch response generated mainly in the auditory cortex and a tactile mismatch response generated in frontal and cerebellar regions. The influence of musical training was seen in the audio-tactile as well as in the auditory condition, indicating enhanced higher-order processing in musicians, while the sources of the tactile MMN were not influenced by long-term musical training. Consistent with the predictive coding model, more basic, bottom-up sensory processing was relatively stable and less affected by expertise, whereas areas for top-down models of multisensory expectancies were modulated by training.

Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors.

PubMed

Wang, Hongbo; de Boer, Greg; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Hewson, Robert; Culmer, Peter

2016-08-24

Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design.

Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors

PubMed Central

Wang, Hongbo; de Boer, Greg; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Hewson, Robert; Culmer, Peter

2016-01-01

Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design. PMID:27563908

Contextual cueing of tactile search is coded in an anatomical reference frame.

PubMed

Assumpção, Leonardo; Shi, Zhuanghua; Zang, Xuelian; Müller, Hermann J; Geyer, Thomas

2018-04-01

This work investigates the reference frame(s) underlying tactile context memory, a form of statistical learning in a tactile (finger) search task. In this task, if a searched-for target object is repeatedly encountered within a stable spatial arrangement of task-irrelevant distractors, detecting the target becomes more efficient over time (relative to nonrepeated arrangements), as learned target-distractor spatial associations come to guide tactile search, thus cueing attention to the target location. Since tactile search displays can be represented in several reference frames, including multiple external and an anatomical frame, in Experiment 1 we asked whether repeated search displays are represented in tactile memory with reference to an environment-centered or anatomical reference frame. In Experiment 2, we went on examining a hand-centered versus anatomical reference frame of tactile context memory. Observers performed a tactile search task, divided into a learning and test session. At the transition between the two sessions, we introduced postural manipulations of the hands (crossed ↔ uncrossed in Expt. 1; palm-up ↔ palm-down in Expt. 2) to determine the reference frame of tactile contextual cueing. In both experiments, target-distractor associations acquired during learning transferred to the test session when the placement of the target and distractors was held constant in anatomical, but not external, coordinates. In the latter, RTs were even slower for repeated displays. We conclude that tactile contextual learning is coded in an anatomical reference frame. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Tactile Cueing for Target Acquisition and Identification

DTIC Science & Technology

2005-09-01

method of coding tactile information, and the method of presenting elevation information were studied. Results: Subjects were divided into video game experienced...VGP) subjects and non- video game (NVGP) experienced subjects. VGPs showed a significantly lower’ target acquisition time with the 12...that video game players performed better with the highest level of tactile resolution, while non- video game players performed better with simpler pattern and a lower resolution display.

Improvement and decline in tactile discrimination behavior after cortical plasticity induced by passive tactile coactivation.

PubMed

Hodzic, Amra; Veit, Ralf; Karim, Ahmed A; Erb, Michael; Godde, Ben

2004-01-14

Perceptual learning can be induced by passive tactile coactivation without attention or reinforcement. We used functional MRI (fMRI) and psychophysics to investigate in detail the specificity of this type of learning for different tactile discrimination tasks and the underlying cortical reorganization. We found that a few hours of Hebbian coactivation evoked a significant increase of primary (SI) and secondary (SII) somatosensory cortical areas representing the stimulated body parts. The amount of plastic changes was strongly correlated with improvement in spatial discrimination performance. However, in the same subjects, frequency discrimination was impaired after coactivation, indicating that even maladaptive processes can be induced by intense passive sensory stimulation.

Effects of Tactile and Audio Cues on Reducing Vestibular Illusions

DTIC Science & Technology

2006-09-01

enlightening . Further, assessment of motion sickness symptoms pre- and post-test would provide valuable information as to any changes in overall well-being...from 18 to 56 years, with a mean age of 38 years. Potential volunteers completed a self-report form identifying any physiological, neurological , and...significant reduction in CE (21 deg/s). When perturbations were applied the effect approached significance (p = 0.0612). The tactile belt and 3-D audio showed

Postural stabilization from fingertip contact II. Relationships between age, tactile sensibility and magnitude of contact forces.

PubMed

Tremblay, François; Mireault, Annie-Claude; Dessureault, Liam; Manning, Hélène; Sveistrup, Heidi

2005-07-01

In the present report, we extend our previous observations on the effect of age on postural stabilization from fingertip contact (Exp Brain Res 157 (2004) 275) to examine the possible influence of sensory thresholds measured at the fingertip on the magnitude of contact forces. Participants (young, n=25, 19-32 years; old, n=35, 60-86 years) underwent psychophysical testing of the right index finger to determine thresholds for spatial acuity, pressure sensitivity and kinesthetic acuity. Spatial acuity was determined from the ability to detect gaps of different widths, while Semmes-Weinstein monofilaments were used for pressure sensitivity. Kinesthetic acuity was determined by asking participants to discriminate plates of different thicknesses using a thumb-index precision grip. These tests were selected on the basis that each reflected different sensory coding mechanisms (resolution of spatial stimuli, detection of mechanical forces and integration of multi-sensory inputs for hand conformation) and thus provided specific information about the integrity and function of mechanoreceptive afferents innervating the hand. After log transformation, thresholds were first examined to determine the influence of age (young and old) and gender (male, female) on tactile acuity. Sensory thresholds were then entered into multiple linear regression models to examine their ability to predict fingertip contact forces (normal and tangential) applied to a smooth surface when subjects stood with eyes closed on either a firm or a compliant support surface. As expected, age exerted a significant effect (p<0.01) on all three thresholds, but its impact was greater on spatial acuity than on pressure sensitivity or kinesthetic acuity. Gender had a marginal impact on pressure sensitivity thresholds only. The regression analyses revealed that tactile thresholds determined at the index fingertip accounted for a substantial proportion of the variance (up to 30%) seen in the contact forces deployed

Re-examining overlap between tactile and visual motion responses within hMT+ and STS

PubMed Central

Jiang, Fang; Beauchamp, Michael S.; Fine, Ione

2015-01-01

Here we examine overlap between tactile and visual motion BOLD responses within the human MT+ complex. Although several studies have reported tactile responses overlapping with hMT+, many used group average analyses, leaving it unclear whether these responses were restricted to sub-regions of hMT+. Moreover, previous studies either employed a tactile task or passive stimulation, leaving it unclear whether or not tactile responses in hMT+ are simply the consequence of visual imagery. Here we carried out a replication of one of the classic papers finding tactile responses in hMT+ (Hagen et al. 2002). We mapped MT and MST in individual subjects using visual field localizers. We then examined responses to tactile motion on the arm, either presented passively or in the presence of a visual task performed at fixation designed to minimize visualization of the concurrent tactile stimulation. To our surprise, without a visual task, we found only weak tactile motion responses in MT (6% of voxels showing tactile responses) and MST (2% of voxels). With an unrelated visual task designed to withdraw attention from the tactile modality, responses in MST reduced to almost nothing (<1% regions). Consistent with previous results, we did observe tactile responses in STS regions superior and anterior to hMT+. Despite the lack of individual overlap, group averaged responses produced strong spurious overlap between tactile and visual motion responses within hMT+ that resembled those observed in previous studies. The weak nature of tactile responses in hMT+ (and their abolition by withdrawal of attention) suggests that hMT+ may not serve as a supramodal motion processing module. PMID:26123373

A preliminary investigation of lumbar tactile acuity in yoga practitioners.

PubMed

Flaherty, Mary; Connolly, Martin

2014-01-01

Tactile acuity in the back relates to voluntary lumbo-pelvic control and is lower in chronic low back pain (CLBP) patients. Two-point discrimination (TPD) thresholds are higher, indicating decreased tactile acuity in patients with CLBP. Yoga has been shown to help relieve CLBP. This study investigated the hypothesis that regular practitioners of yoga have increased tactile acuity (i.e., lower TPD thresholds) when compared to matched controls who regularly perform gym-based (resistance training or aerobic-type) exercise. Tactile acuity in the low back was assessed using TPD in 16 long-term practitioners of yoga (5 Ashtanga, 5 Bikram, and 6 Iyengar practitioners) and 16 age- and gender-matched healthy controls who exercise (with weights and aerobic exercise). The yoga practitioners' TPD was lower than that of the exercisers, indicating greater tactile acuity in the low back. While there was no difference between the TPD of the practitioners of different yoga styles, the TPD of the Ashtanga yoga participants were significantly lower than those of the exercisers. The yogis whose main reasons to practice yoga were for "meditation or increased mindfulness" and for "well-being" showed a nonsignificant trend of higher tactile acuity than those who did yoga for "physical exercise." There was no association between TPD threshold and cumulative amount of yoga practice in terms of hours per week and years of experience. However, increased hours of exercise per week correlated with higher TPD. The findings suggest that there may be a relationship between yoga practice and enhanced tactile acuity in the low back.

Inert gas narcosis has no influence on thermo-tactile sensation.

PubMed

Jakovljević, Miroljub; Vidmar, Gaj; Mekjavic, Igor B

2012-05-01

Contribution of skin thermal sensors under inert gas narcosis to the raising hypothermia is not known. Such information is vital for understanding the impact of narcosis on behavioural thermoregulation, diver safety and judgment of thermal (dis)comfort in the hyperbaric environment. So this study aimed at establishing the effects of normoxic concentration of 30% nitrous oxide (N(2)O) on thermo-tactile threshold sensation by studying 16 subjects [eight females and eight males; eight sensitive (S) and eight non-sensitive (NS) to N(2)O]. Their mean (SD) age was 22.1 (1.8) years, weight 72.8 (15.3) kg, height 1.75 (0.10) m and body mass index 23.8 (3.8) kg m(-2). Quantitative thermo-tactile sensory testing was performed on forearm, upper arm and thigh under two experimental conditions: breathing air (air trial) and breathing normoxic mixture of 30% N(2)O (N(2)O trial) in the mixed sequence. Difference in thermo-tactile sensitivity thresholds between two groups of subjects in two experimental conditions was analysed by 3-way mixed-model analysis of covariance. There were no statistically significant differences in thermo-tactile thresholds either between the Air and N(2)O trials, or between S and NS groups, or between females and males, or with respect to body mass index. Some clinically insignificant lowering of thermo-tactile thresholds occurred only for warm thermo-tactile thresholds on upper arm and thigh. The results indicated that normoxic mixture of 30% N(2)O had no influence on thermo-tactile sensation in normothermia.

Development of tactile sensory circuits in the CNS.

PubMed

Iwasato, Takuji; Erzurumlu, Reha S

2018-06-13

Molecular identification of neuronal types and genetic and imaging approaches to characterize their properties reveal morphological, physiological and dynamic aspects of sensory circuit development. Here we focus on the mouse tactile sensory circuitry, with particular emphasis on the main trigeminal pathway that connects the whiskers, the major tactile organ in rodents, to the neocortex. At each level of this pathway, neurogenesis, axonal elongation, pathfinding, target recognition and circuit reorganization including dendritic refinement of cortical layer 4 neurons occur contemporaneously and a multitude of molecular signals are used in differing combinations. We highlight recent advances in development of tactile circuitry and note gaps in our understanding. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prototype tactile feedback system for examination by skin touch.

PubMed

Lee, O; Lee, K; Oh, C; Kim, K; Kim, M

2014-08-01

Diagnosis of conditions such as psoriasis and atopic dermatitis, in the case of induration, involves palpating the infected area via hands and then selecting a ratings score. However, the score is determined based on the tester's experience and standards, making it subjective. To provide tactile feedback on the skin, we developed a prototype tactile feedback system to simulate skin wrinkles with PHANToM OMNI. To provide the user with tactile feedback on skin wrinkles, a visual and haptic Augmented Reality system was developed. First, a pair of stereo skin images obtained by a stereo camera generates a disparity map of skin wrinkles. Second, the generated disparity map is sent to an implemented tactile rendering algorithm that computes a reaction force according to the user's interaction with the skin image. We first obtained a stereo image of skin wrinkles from the in vivo stereo imaging system, which has a baseline of 50.8 μm, and obtained the disparity map with a graph cuts algorithm. The left image is displayed on the monitor to enable the user to recognize the location visually. The disparity map of the skin wrinkle image sends skin wrinkle information as a tactile response to the user through a haptic device. We successfully developed a tactile feedback system for virtual skin wrinkle simulation by means of a commercialized haptic device that provides the user with a single point of contact to feel the surface roughness of a virtual skin sample. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Check-All-That-Apply (CATA), Sorting, and Polarized Sensory Positioning (PSP) with Astringent Stimuli

PubMed Central

Fleming, Erin E.; Ziegler, Gregory R.; Hayes, John E.

2015-01-01

Multiple rapid sensory profiling techniques have been developed as more efficient alternatives to traditional sensory descriptive analysis. Here, we compare the results of three rapid sensory profiling techniques – check-all-that-apply (CATA), sorting, and polarized sensory positioning (PSP) – using a diverse range of astringent stimuli. These rapid methods differ in their theoretical basis, implementation, and data analyses, and the relative advantages and limitations are largely unexplored. Additionally, we were interested in using these methods to compare varied astringent stimuli, as these compounds are difficult to characterize using traditional descriptive analysis due to high fatigue and potential carry-over. In the CATA experiment, subjects (n=41) were asked to rate the overall intensity of each stimulus as well as to endorse any relevant terms (from a list of 13) which characterized the sample. In the sorting experiment, subjects (n=30) assigned intensity-matched stimuli into groups 1-on-1 with the experimenter. In the PSP experiment, (n=41) subjects first sampled and took notes on three blind references (‘poles’) before rating each stimulus for its similarity to each of the 3 poles. Two-dimensional perceptual maps from correspondence analysis (CATA), multidimensional scaling (sorting), and multiple factor analysis (PSP) were remarkably similar, with normalized RV coefficients indicating significantly similar plots, regardless of method. Agglomerative hierarchical clustering of all data sets using Ward’s minimum variance as the linkage criteria showed the clusters of astringent stimuli were approximately based on the respective class of astringent agent. Based on the descriptive CATA data, it appears these differences may be due to the presence of side tastes such as bitterness and sourness, rather than astringent sub-qualities per se. Although all three methods are considered ‘rapid,’ our prior experience with sorting suggests it is best

Nitrogen narcosis and tactile shape memory in low visibility.

PubMed

van Wijk, Charles H; Meintjes, W A J

2014-01-01

Commercial diving often occurs in low visibility, where divers are reliant on their tactile senses. This study examined the effect of nitrogen narcosis on tactile memory for shapes as well as the influence of psychological and biographical factors on this relationship. This crossover study tested 139 commercial divers in a dry hyperbaric chamber at 101.325 and 607.95 kPa (1 and 6 atmospheres absolute/atm abs). Divers memorized shapes while blindfolded, using their tactile senses only. Delayed recall was measured at the surface after each dive. Psychological and biographical data were also collected. A significant effect of hyperbaric pressure on tactile memory was demonstrated, and a further effect of sequence of testing found. Thus, divers' delayed shape recall deteriorated by 8% after learning material at depth, compared to learning on the surface. There were also significant but small effects of psychological and biographical markers on tactile memory performance, with lower trait anxiety associated with better recall, and lower education associated with poorer recall. The findings emphasize the importance of utilizing other forms of recording of events or objects at depth, particularly in conditions of low visibility during deeper diving, to aid memory encoding and subsequent recall at the surface.

Meet our Neighbours - a tactile experience

NASA Astrophysics Data System (ADS)

Canas, L.; Lobo Correia, A.

2013-09-01

Planetary science is a key field in astronomy that draws lots of attention and that engages large amounts of enthusiasts. On its essence, it is a visual science and the current resources and activities for the inclusion of visually impaired children, although increasing, are still costly and somewhat scarce. Therefore there is a paramount need to develop more low cost resources in order to provide experiences that can reach all, even the more socially deprived communities. "Meet our neighbours!-a tactile experience", plans to promote and provide inclusion activities for visually impaired children and their non-visually impaired peers through the use of astronomy hands-on low cost activities. Is aimed for children from the ages of 6 to 12 years old and produce data set 13 tactile images of the main objects of the Solar System that can be used in schools, science centres and outreach associations. Accessing several common problems through tactile resources, with this project we present ways to successfully provide low cost solutions (avoiding the expensive tactile printing costs), promote inclusion and interactive hands-on activities for visually impaired children and their non-visually impaired peers and create dynamic interactions based on oral knowledge transmission between them. Here we describe the process of implementing such initiative near target communities: establishing a bridge between scientists, children and teachers. The struggles and challenges perceived during the project and the enrichment experience of engaging astronomy with these specific groups, broadening horizons in an overall experience accessible to all.

Evolutionary Specialization of Tactile Perception in Vertebrates.

PubMed

Schneider, Eve R; Gracheva, Elena O; Bagriantsev, Slav N

2016-05-01

Evolution has endowed vertebrates with the remarkable tactile ability to explore the world through the perception of physical force. Yet the sense of touch remains one of the least well understood senses at the cellular and molecular level. Vertebrates specializing in tactile perception can highlight general principles of mechanotransduction. Here, we review cellular and molecular adaptations that underlie the sense of touch in typical and acutely mechanosensitive vertebrates. ©2016 Int. Union Physiol. Sci./Am. Physiol. Soc.

Braille in the Sighted: Teaching Tactile Reading to Sighted Adults.

PubMed

Bola, Łukasz; Siuda-Krzywicka, Katarzyna; Paplińska, Małgorzata; Sumera, Ewa; Hańczur, Paweł; Szwed, Marcin

2016-01-01

Blind people are known to have superior perceptual abilities in their remaining senses. Several studies suggest that these enhancements are dependent on the specific experience of blind individuals, who use those remaining senses more than sighted subjects. In line with this view, sighted subjects, when trained, are able to significantly progress in relatively simple tactile tasks. However, the case of complex tactile tasks is less obvious, as some studies suggest that visual deprivation itself could confer large advantages in learning them. It remains unclear to what extent those complex skills, such as braille reading, can be learnt by sighted subjects. Here we enrolled twenty-nine sighted adults, mostly braille teachers and educators, in a 9-month braille reading course. At the beginning of the course, all subjects were naive in tactile braille reading. After the course, almost all were able to read whole braille words at a mean speed of 6 words-per-minute. Subjects with low tactile acuity did not differ significantly in braille reading speed from the rest of the group, indicating that low tactile acuity is not a limiting factor for learning braille, at least at this early stage of learning. Our study shows that most sighted adults can learn whole-word braille reading, given the right method and a considerable amount of motivation. The adult sensorimotor system can thus adapt, to some level, to very complex tactile tasks without visual deprivation. The pace of learning in our group was comparable to congenitally and early blind children learning braille in primary school, which suggests that the blind's mastery of complex tactile tasks can, to a large extent, be explained by experience-dependent mechanisms.

Braille in the Sighted: Teaching Tactile Reading to Sighted Adults

PubMed Central

Bola, Łukasz; Siuda-Krzywicka, Katarzyna; Paplińska, Małgorzata; Sumera, Ewa; Hańczur, Paweł; Szwed, Marcin

2016-01-01

Blind people are known to have superior perceptual abilities in their remaining senses. Several studies suggest that these enhancements are dependent on the specific experience of blind individuals, who use those remaining senses more than sighted subjects. In line with this view, sighted subjects, when trained, are able to significantly progress in relatively simple tactile tasks. However, the case of complex tactile tasks is less obvious, as some studies suggest that visual deprivation itself could confer large advantages in learning them. It remains unclear to what extent those complex skills, such as braille reading, can be learnt by sighted subjects. Here we enrolled twenty-nine sighted adults, mostly braille teachers and educators, in a 9-month braille reading course. At the beginning of the course, all subjects were naive in tactile braille reading. After the course, almost all were able to read whole braille words at a mean speed of 6 words-per-minute. Subjects with low tactile acuity did not differ significantly in braille reading speed from the rest of the group, indicating that low tactile acuity is not a limiting factor for learning braille, at least at this early stage of learning. Our study shows that most sighted adults can learn whole-word braille reading, given the right method and a considerable amount of motivation. The adult sensorimotor system can thus adapt, to some level, to very complex tactile tasks without visual deprivation. The pace of learning in our group was comparable to congenitally and early blind children learning braille in primary school, which suggests that the blind’s mastery of complex tactile tasks can, to a large extent, be explained by experience-dependent mechanisms. PMID:27187496

Neural Bases of Peri-Hand Space Plasticity through Tool-Use: Insights from a Combined Computational-Experimental Approach

ERIC Educational Resources Information Center

Magosso, Elisa; Ursino, Mauro; di Pellegrino, Giuseppe; Ladavas, Elisabetta; Serino, Andrea

2010-01-01

Visual peripersonal space (i.e., the space immediately surrounding the body) is represented by multimodal neurons integrating tactile stimuli applied on a body part with visual stimuli delivered near the same body part, e.g., the hand. Tool use may modify the boundaries of the peri-hand area, where vision and touch are integrated. The neural…

High-pressure endurable flexible tactile actuator based on microstructured dielectric elastomer

NASA Astrophysics Data System (ADS)

Pyo, Dongbum; Ryu, Semin; Kyung, Ki-Uk; Yun, Sungryul; Kwon, Dong-Soo

2018-02-01

We demonstrate a robust flexible tactile actuator that is capable of working under high external pressures. The tactile actuator is based on a pyramidal microstructured dielectric elastomer layer inducing variation in both mechanical and dielectric properties. The vibrational performance of the actuator can be modulated by changing the geometric parameter of the microstructures. We evaluated the performance of the actuator under high-pressure loads up to 25 kPa, which is over the typical range of pressure applied when humans touch or manipulate objects. Due to the benefit of nonlinearity of the pyramidal structure, the actuator could maintain high mechanical output under various external pressures in the frequency range of 100-200 Hz, which is the most sensitive to vibration acceleration for human finger pads. The responses are not only fast, reversible, and highly durable under consecutive cyclic operations, but also large enough to impart perceivable vibrations for haptic feedback on practical wearable device applications.

Laser-induced thermoelastic effects can evoke tactile sensations

NASA Astrophysics Data System (ADS)

Jun, Jae-Hoon; Park, Jong-Rak; Kim, Sung-Phil; Min Bae, Young; Park, Jang-Yeon; Kim, Hyung-Sik; Choi, Seungmoon; Jung, Sung Jun; Hwa Park, Seung; Yeom, Dong-Il; Jung, Gu-In; Kim, Ji-Sun; Chung, Soon-Cheol

2015-06-01

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance. We demonstrate such tactile stimulation can be enabled by laser-induced thermoelastic effects by means of physical and perceptual studies, as well as simulations. In the physical study, the mechanical effect of laser on a human skin sample is detected using low-power radiation in accordance with safety guidelines. Limited increases (< ~2.5 °C) in temperature at the surface of the skin, examined by both thermal camera and the Monte Carlo simulation, indicate that laser does not evoke heat-induced nociceptive sensation. In the human EEG study, brain responses to both mechanical and laser stimulation are consistent, along with subjective reports of the non-nociceptive sensation of laser stimuli.

Laser-induced thermoelastic effects can evoke tactile sensations.

PubMed

Jun, Jae-Hoon; Park, Jong-Rak; Kim, Sung-Phil; Min Bae, Young; Park, Jang-Yeon; Kim, Hyung-Sik; Choi, Seungmoon; Jung, Sung Jun; Hwa Park, Seung; Yeom, Dong-Il; Jung, Gu-In; Kim, Ji-Sun; Chung, Soon-Cheol

2015-06-05

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance. We demonstrate such tactile stimulation can be enabled by laser-induced thermoelastic effects by means of physical and perceptual studies, as well as simulations. In the physical study, the mechanical effect of laser on a human skin sample is detected using low-power radiation in accordance with safety guidelines. Limited increases (< ~2.5 °C) in temperature at the surface of the skin, examined by both thermal camera and the Monte Carlo simulation, indicate that laser does not evoke heat-induced nociceptive sensation. In the human EEG study, brain responses to both mechanical and laser stimulation are consistent, along with subjective reports of the non-nociceptive sensation of laser stimuli.

Tactile display device using an electrorheological fluid

NASA Technical Reports Server (NTRS)

Garner, H. Douglas (Inventor)

1994-01-01

A tactile display device utilizes an electrorheological fluid to activate a plurality of tactile dots. A voltage is selectively produced uniformly across an electrorheological fluid flowing between a common ground electrode and a plurality of conductive dot electrodes, thereby producing an increase in the fluid's viscosity to the extent that fluid flow between the two electrodes is restricted. The flow restriction produces a build-up of electrorheological fluid in a corresponding dot actuator chamber. The resulting pressure increase in the chamber displaces an elastic diaphragm fixed to a display surface to form a lump which can be perceived by the reader as one dot in a Braille character cell. A flow regulation system provides a continually pressurized flow system and provides for free flow of the electrorheological fluid through the plurality of dot actuator chambers when they are not activated. The device is adaptable to printed circuit techniques and can simultaneously display tactile dots representative of a full page of Braille characters stored on a medium such as a tape cassette or to display tactile dots representative of non-Braille data appearing on a computer monitor or contained on another data storage medium. In an alternate embodiment, the elastic diaphragm drives a plurality of spring-loaded pins provided with positive stops to maintain consistent displacements of the pins in both their actuated and nonactuated positions.

Tactile Acuity Charts: A Reliable Measure of Spatial Acuity

PubMed Central

Bruns, Patrick; Camargo, Carlos J.; Campanella, Humberto; Esteve, Jaume; Dinse, Hubert R.; Röder, Brigitte

2014-01-01

For assessing tactile spatial resolution it has recently been recommended to use tactile acuity charts which follow the design principles of the Snellen letter charts for visual acuity and involve active touch. However, it is currently unknown whether acuity thresholds obtained with this newly developed psychophysical procedure are in accordance with established measures of tactile acuity that involve passive contact with fixed duration and control of contact force. Here we directly compared tactile acuity thresholds obtained with the acuity charts to traditional two-point and grating orientation thresholds in a group of young healthy adults. For this purpose, two types of charts, using either Braille-like dot patterns or embossed Landolt rings with different orientations, were adapted from previous studies. Measurements with the two types of charts were equivalent, but generally more reliable with the dot pattern chart. A comparison with the two-point and grating orientation task data showed that the test-retest reliability of the acuity chart measurements after one week was superior to that of the passive methods. Individual thresholds obtained with the acuity charts agreed reasonably with the grating orientation threshold, but less so with the two-point threshold that yielded relatively distinct acuity estimates compared to the other methods. This potentially considerable amount of mismatch between different measures of tactile acuity suggests that tactile spatial resolution is a complex entity that should ideally be measured with different methods in parallel. The simple test procedure and high reliability of the acuity charts makes them a promising complement and alternative to the traditional two-point and grating orientation thresholds. PMID:24504346

Tactile arousal threshold of sleeping king penguins in a breeding colony.

PubMed

Dewasmes, G; Telliez, F

2000-09-01

The tactile arousal threshold of sleeping birds has not been investigated to date. In this study, the characteristics of this threshold were assessed by stimulating either the upper back or a foot of two groups (one cutaneous site per group) of 60 sleeping king penguins (Aptenodytes patagonica) in the breeding colony of Baie du Marin (Crozet Archipelago). Increasing weights were put onto one of the feet or the upper back of individuals that had been sleeping for more than 5 min until they showed behavioural signs of arousal (head raising). The weight applied to the upper back that was needed to awaken a sleeper (837 +/- 73 g) was 20 times greater than that applied to a foot (38 +/- 6 g). In terms of pressure, the difference remained five times higher for the back (209 +/- 18 g/cm(2)) than the foot (40 g +/- 7 g/cm(2)). Because the king penguin incubates its single egg and rears its young chick on its feet, the low threshold measured at this level could be viewed as an adaptation against progeny predation. Sleepers are frequently bumped by conspecifics walking through the colony. The increased arousal threshold associated with tactile stimulation of the back may help to preserve sleep continuity under these conditions.

How to identify water from thickener aqueous solutions by touch.

PubMed

Nonomura, Yoshimune; Miura, Taku; Miyashita, Takaaki; Asao, Yuka; Shirado, Hirokazu; Makino, Yasutoshi; Maeno, Takashi

2012-06-07

Water detection is one of the most crucial psychological processes for many animals. However, nobody knows the perception mechanism of water through our tactile sense. In the present study, we found that a characteristic frictional stimulus with large acceleration is one of the cues to differentiate water from water contaminated with thickener. When subjects applied small amounts of water to a glass plate, strong stick-slip phenomena with a friction force of 0.46 ± 0.30 N and a vertical force of 0.57 ± 0.36 N were observed at the skin surface, as shown in previous studies. Surprisingly, periodic shears with acceleration seven times greater than gravitational acceleration occurred during the application process. Finite-element analyses predicted that these strong stimuli could activate tactile receptors: Meissner's corpuscle and Pacinians. When such stimuli were applied to the fingertips by an ultrasonic vibrator, a water-like tactile texture was perceived by some subjects, even though no liquid was present between the fingertip and the vibrator surface. These findings could potentially be applied in the following areas: materials science, information technology, medical treatment and entertainment.

How to identify water from thickener aqueous solutions by touch

PubMed Central

Nonomura, Yoshimune; Miura, Taku; Miyashita, Takaaki; Asao, Yuka; Shirado, Hirokazu; Makino, Yasutoshi; Maeno, Takashi

2012-01-01

Water detection is one of the most crucial psychological processes for many animals. However, nobody knows the perception mechanism of water through our tactile sense. In the present study, we found that a characteristic frictional stimulus with large acceleration is one of the cues to differentiate water from water contaminated with thickener. When subjects applied small amounts of water to a glass plate, strong stick-slip phenomena with a friction force of 0.46 ± 0.30 N and a vertical force of 0.57 ± 0.36 N were observed at the skin surface, as shown in previous studies. Surprisingly, periodic shears with acceleration seven times greater than gravitational acceleration occurred during the application process. Finite-element analyses predicted that these strong stimuli could activate tactile receptors: Meissner's corpuscle and Pacinians. When such stimuli were applied to the fingertips by an ultrasonic vibrator, a water-like tactile texture was perceived by some subjects, even though no liquid was present between the fingertip and the vibrator surface. These findings could potentially be applied in the following areas: materials science, information technology, medical treatment and entertainment. PMID:22072449

Force/torque and tactile sensors for sensor-based manipulator control

NASA Technical Reports Server (NTRS)

Vanbrussel, H.; Belieen, H.; Bao, Chao-Ying

1989-01-01

The autonomy of manipulators, in space and in industrial environments, can be dramatically enhanced by the use of force/torque and tactile sensors. The development and future use of a six-component force/torque sensor for the Hermes Robot Arm (HERA) Basic End-Effector (BEE) is discussed. Then a multifunctional gripper system based on tactile sensors is described. The basic transducing element of the sensor is a sheet of pressure-sensitive polymer. Tactile image processing algorithms for slip detection, object position estimation, and object recognition are described.

Resonant vibrating sensors for tactile tissue differentiation

NASA Astrophysics Data System (ADS)

Hemsel, T.; Stroop, R.; Oliva Uribe, D.; Wallaschek, J.

2007-12-01

Surgical resection of brain tumours is a difficult task. To enhance surgery results, a tactile sensor is wanted that gives better resolution and sensitivity than the human tactile sense. The characteristics of resonant vibrating piezoelectric elements change with varying load. This allows for calculation of mechanical load parameters by measuring electrical quantities. Different setups of piezoelectric sensors have been used to investigate soft materials. Finally, a piezoelectric bimorph sensor gave good results for distinguishing tissue mimicking gel-phantoms with different gelatine concentrations.

Scalable fabric tactile sensor arrays for soft bodies

NASA Astrophysics Data System (ADS)

Day, Nathan; Penaloza, Jimmy; Santos, Veronica J.; Killpack, Marc D.

2018-06-01

Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist.

Nano opto-mechanical systems (NOMS) as a proposal for tactile displays

NASA Astrophysics Data System (ADS)

Campo, E. M.; Roig, J.; Roeder, B.; Wenn, D.; Mamojka, B.; Omastova, M.; Terentjev, E. M.; Esteve, J.

2011-10-01

For over a decade, special emphasis has been placed in the convergence of different fields of science and technology, in an effort to serve human needs by way of enhancing human capabilities. The convergence of the Nano-Bio-Info-Cogni (NBIC) quartet will provide unique solutions to specific needs. This is the case of, Nano-opto mechanical Systems (NOMS), presented as a solution to tactile perception, both for the visually-impaired and for the general public. NOMS, based on photoactive polymer actuators and devices, is a much sought-after technology. In this scheme, light sources promote mechanical actuation producing a variety of nano-opto mechanical systems such as nano-grippers. In this paper, we will provide a series of specifications that the NOMS team is targeting towards the development of a tactile display using optically-activated smart materials. Indeed, tactile displays remain mainly mechanical, compromising reload speeds and resolution which inhibit 3D tactile representation of web interfaces. We will also discuss how advantageous NOMS tactile displays could be for the general public. Tactile processing based on stimulation delivered through the NOMS tablet, will be tested using neuropsychology methods, in particular event-related brain potentials. Additionally, the NOMS tablet will be instrumental to the development of basic neuroscience research.

C-Tactile Mediated Erotic Touch Perception Relates to Sexual Desire and Performance in a Gender-Specific Way.

PubMed

Bendas, Johanna; Georgiadis, Janniko R; Ritschel, Gerhard; Olausson, Håkan; Weidner, Kerstin; Croy, Ilona

2017-05-01

Unmyelinated low-threshold mechanoreceptors-the so-called C-tactile (CT) afferents-play a crucial role in the perception and conduction of caressing and pleasant touch sensations and significantly contribute to the concept of erotic touch perception. To investigate the relations between sexual desire and sexual performance and the perception of touch mediated by CT afferents. Seventy healthy participants (28 men, 42 women; mean age ± SD = 24.84 ± 4.08 years, range = 18-36 years) underwent standardized and highly controlled stroking stimulation that varied in the amount of CT fiber stimulation by changing stroking velocity (CT optimal = 1, 3 and 10 cm/s; CT suboptimal = 0.1, 0.3, and 30 cm/s). Participants rated the perceived pleasantness, eroticism, and intensity of the applied tactile stimulation on a visual analog scale, completed the Sexual Desire Inventory, and answered questions about sexual performance. Ratings of perceived eroticism of touch were related to self-report levels of sexual desire and sexual performance. Pleasantness and eroticism ratings showed similar dependence on stroking velocity that aligned with the activity of CT afferents. Erotic touch perception was related to sexual desire and sexual performance in a gender-specific way. In women, differences in eroticism ratings between CT optimal and suboptimal velocities correlated positively with desire for sexual interaction. In contrast, in men, this difference correlated to a decreased frequency and longer duration of partnered sexual activities. The present results lay the foundation for future research assessing these relations in patients with specific impairments of sexual functioning (eg, hypoactive sexual desire disorder). The strength of the study is the combination of standardized neurophysiologic methods and behavioral data. A clear limitation of the study design is the exclusion of exact data on the female menstrual cycle and the recruitment of an inhomogeneous sample

Can tactile sensory processing differentiate between children with autistic disorder and asperger's disorder?

PubMed

Ghanizadeh, Ahmad

2011-05-01

There are debates whether autistic disorder (autism) and Asperger's disorder are two distinct disorders. Moreover, interventional sensory occupational therapy should consider the clinical characteristics of patients. Already, commonalities and differences between Asperger's disorder and autistic disorder are not well studied. The aim of this study is to compare tactile sensory function of children with autistic disorder and children with Asperger's disorder. Tactile sensory function was compared between 36 children with autism and 19 children with Asperger's disorder. The two disorders were diagnosed based on Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision. The parent-reported Tactile Dysfunction Checklist was used to assess the three aspects of hypersensitivity, hyposensitivity, and poor tactile perception and discrimination. Developmental coordination was also assessed. Developmental coordination problems total score was not associated with group. The mean (standard deviation) score of tactile hyper-responsivity was not different between the groups. Tactile hyporesponsivity and poor tactile perception and discrimination scores were statistically higher in autistic disorder than Asperger's disorder group. These results for the first time indicated that at least some aspects of tactile perception can differentiate these two disorders. Children with autistic disorder have more tactile sensory seeking behaviors than children with Asperger's disorder. Moreover, the ability of children with autistic disorder for tactile discrimination and sensory perception is less than those with Asperger's disorder. Interventional sensory therapy in children with autistic disorder should have some characteristics that can be different and specific for children with Asperger's disorder. Formal intelligence quotient testing was not performed on all of the children evaluated, which is a limitation to this study. In some cases, a clinical estimation of

Intradermal administration of magnesium sulphate and magnesium chloride produces hypesthesia to mechanical but hyperalgesia to heat stimuli in humans

PubMed Central

Ushida, Takahiro; Iwatsu, Osamu; Shimo, Kazuhiro; Tetsunaga, Tomoko; Ikeuchi, Masahiko; Ikemoto, Tatsunori; Arai, Young-Chang P; Suetomi, Katsutoshi; Nishihara, Makoto

2009-01-01

Background Although magnesium ions (Mg2+) are known to display many similar features to other 2+ charged cations, they seem to have quite an important and unique role in biological settings, such as NMDA blocking effect. However, the role of Mg2+ in the neural transmission system has not been studied as sufficiently as calcium ions (Ca2+). To clarify the sensory effects of Mg2+ in peripheral nervous systems, sensory changes after intradermal injection of Mg2+ were studied in humans. Methods Magnesium sulphate, magnesium chloride and saline were injected into the skin of the anterior region of forearms in healthy volunteers and injection-induced irritating pain ("irritating pain", for short), tactile sensation, tactile pressure thresholds, pinch-pain changes and intolerable heat pain thresholds of the lesion were monitored. Results Flare formation was observed immediately after magnesium sulphate or magnesium chloride injection. We found that intradermal injections of magnesium sulphate and magnesium chloride transiently caused irritating pain, hypesthesia to noxious and innocuous mechanical stimulations, whereas secondary hyperalgesia due to mechanical stimuli was not observed. In contrast to mechanical stimuli, intolerable heat pain-evoking temperature was significantly decreased at the injection site. In addition to these results, spontaneous pain was immediately attenuated by local cooling. Conclusion Membrane-stabilizing effect and peripheral NMDA-blocking effect possibly produced magnesium-induced mechanical hypesthesia, and extracellular cation-induced sensitization of TRPV1 channels was thought to be the primary mechanism of magnesium-induced heat hyperalgesia. PMID:19715604

A reconfigurable tactile display based on polymer MEMS technology

NASA Astrophysics Data System (ADS)

Wu, Xiaosong

A tactile display provides information such as shape, texture, temperature, and hardness to a user. Ultimately, a tactile display could be used to recreate a virtual object that may be stored in a computer. However, such advanced displays are not yet widely available, primarily due to the lack of low cost, large area, compact actuator arrays that can stimulate the large numbers of receptors of the user and that can also meet the high requirements for user safety and comfort. This research focuses on the development of polymer microfabrication technologies for the realization of two major components of a pneumatic tactile display: a microactuator array and a complementary microvalve (control) array. In this work, the concept, fabrication, and characterization of a kinematically-stabilized polymeric microbubble actuator ("endoskeletal microbubble actuator") is presented. A systematic design and modeling procedure was carried out to generate an optimized geometry of the corrugated diaphragm to satisfy membrane deflection, force, and stability requirements set forth by the tactile display goals. A mass-manufacturable actuator has been fabricated using the approaches of lithography and micromolding. A prototype of a single endoskeletal bubble actuator with a diameter of 2.6mm has been fabricated and characterized. In addition, in order to further reduce the size and cost of the tactile display, a microvalve array can be integrated into the tactile display system to control the pneumatic fluid that actuates the microbubble actuator. A piezoelectrically-driven and hydraulically-amplified polymer microvalve has been designed, fabricated, and tested. An incompressible elastomer was used as a solid hydraulic medium to convert the small axial displacement of a piezoelectric actuator into a large valve head stroke while maintaining a large blocking force. The function of the microvalve as an on-off switch for a pneumatic microbubble tactile actuator has been demonstrated

Revealing unobserved factors underlying cortical activity with a rectified latent variable model applied to neural population recordings.

PubMed

Whiteway, Matthew R; Butts, Daniel A

2017-03-01

The activity of sensory cortical neurons is not only driven by external stimuli but also shaped by other sources of input to the cortex. Unlike external stimuli, these other sources of input are challenging to experimentally control, or even observe, and as a result contribute to variability of neural responses to sensory stimuli. However, such sources of input are likely not "noise" and may play an integral role in sensory cortex function. Here we introduce the rectified latent variable model (RLVM) in order to identify these sources of input using simultaneously recorded cortical neuron populations. The RLVM is novel in that it employs nonnegative (rectified) latent variables and is much less restrictive in the mathematical constraints on solutions because of the use of an autoencoder neural network to initialize model parameters. We show that the RLVM outperforms principal component analysis, factor analysis, and independent component analysis, using simulated data across a range of conditions. We then apply this model to two-photon imaging of hundreds of simultaneously recorded neurons in mouse primary somatosensory cortex during a tactile discrimination task. Across many experiments, the RLVM identifies latent variables related to both the tactile stimulation as well as nonstimulus aspects of the behavioral task, with a majority of activity explained by the latter. These results suggest that properly identifying such latent variables is necessary for a full understanding of sensory cortical function and demonstrate novel methods for leveraging large population recordings to this end. NEW & NOTEWORTHY The rapid development of neural recording technologies presents new opportunities for understanding patterns of activity across neural populations. Here we show how a latent variable model with appropriate nonlinear form can be used to identify sources of input to a neural population and infer their time courses. Furthermore, we demonstrate how these sources are

E-Pad: a comfortable electrocutaneous-based tactile feedback display

NASA Astrophysics Data System (ADS)

Wang, Jiabin; Zhao, Lu; Liu, Yue; Wang, Yongtian; Cai, Yi

2018-01-01

The devices with touchscreen are becoming more popular recently; however, most of them suffer from the crucial drawbacks of lacking accurate tactile feedback. A novel electrocutaneous-based tactile device with the name of E-pad is proposed to provide a dynamic and static low-voltage feedback for touchscreen. We optimize the key parameters of the output voltage and design custom-made hardwares to guarantee a comfortable user experience. Users could move their fingers freely across the touchscreen of the proposed device to really feel virtual objects. Two preliminary experiments are conducted to evaluate the interactive performance of the proposed device and the experimental results show that the proposed device can provide a comfortable and distinct tactile feedback.

Use of tactile materials for Astronomy teaching for visually- and hearing- impaired public schools in Minas Gerais

NASA Astrophysics Data System (ADS)

Paganotti, A.; Reis, C.; Voelzke, M. R.

2017-12-01

This work deals with the use of tactile materials as a pedagogical tool for the teaching of Astronomy, and this material was used in a didactic activity with 44 students of the public elementary school in Minas Gerais. A visually impaired student and another hearing impaired participated, being these the focus of the research. With the tactile visual material elaborated, the objective was to develop themes such as phases of the Moon, eclipses and Solar System. Two questionnaires were applied and revealed an improvement in the concepts related to Astronomy and in the socialization of disabled students with the group after the didactic activity.

Tactile Sensitivity of Children: Effects of Frequency, Masking, and the Non-Pacinian I Psychophysical Channel

ERIC Educational Resources Information Center

Guclu, Burak; Oztek, Cigdem

2007-01-01

Tactile perception depends on the contributions of four psychophysical tactile channels mediated by four corresponding receptor systems. The sensitivity of the tactile channels is determined by detection thresholds that vary as a function of the stimulus frequency. It has been widely reported that tactile thresholds increase (i.e., sensitivity…

Multisensory effects on somatosensation: a trimodal visuo-vestibular-tactile interaction

PubMed Central

Kaliuzhna, Mariia; Ferrè, Elisa Raffaella; Herbelin, Bruno; Blanke, Olaf; Haggard, Patrick

2016-01-01

Vestibular information about self-motion is combined with other sensory signals. Previous research described both visuo-vestibular and vestibular-tactile bilateral interactions, but the simultaneous interaction between all three sensory modalities has not been explored. Here we exploit a previously reported visuo-vestibular integration to investigate multisensory effects on tactile sensitivity in humans. Tactile sensitivity was measured during passive whole body rotations alone or in conjunction with optic flow, creating either purely vestibular or visuo-vestibular sensations of self-motion. Our results demonstrate that tactile sensitivity is modulated by perceived self-motion, as provided by a combined visuo-vestibular percept, and not by the visual and vestibular cues independently. We propose a hierarchical multisensory interaction that underpins somatosensory modulation: visual and vestibular cues are first combined to produce a multisensory self-motion percept. Somatosensory processing is then enhanced according to the degree of perceived self-motion. PMID:27198907

A Tactile Stimulator for Studying Passive Shape Perception

PubMed Central

Lane, John W.; Fitzgerald, Paul J.; Yau, Jeffrey M.; Pembeci, Izzet; Hsiao, Steven S.

2009-01-01

We describe a computer-controlled tactile stimulator for use in human psychophysical and monkey neurophysiological studies of 3-D shape perception. The stimulator is constructed primarily of commercially available parts, as well as a few custom-built pieces for which we will supply diagrams upon request. There are two components to the stimulator: a tactile component and a hand positioner component. The tactile component consists of multiple stimulating units that move about in a Cartesian plane above the restrained hand. Each stimulating unit contains a servo-controlled linear motor with an attached small rotary stepper motor, allowing arbitrary stimulus shapes to contact the skin through vibration, static indentation, or scanning. The hand positioner component modifies the conformation of the restrained hand through a set of mechanical linkages under motorized control. The present design controls the amount of spread between digits two and three, the spread between digits four and three, and the degree to which digit three is flexed or extended, thereby simulating different conformations of the hand in contact with objects. This design is easily modified to suit the needs of the experimenter. Because the two components of the stimulator are independently controlled, the stimulator allows for parametric study of the mechanoreceptive and proprioceptive contributions to 3-D tactile shape perception. PMID:19800916

Tactile short-term memory in sensory-deprived individuals.

PubMed

Papagno, Costanza; Minniti, Giovanna; Mattavelli, Giulia C; Mantovan, Lara; Cecchetto, Carlo

2017-02-01

To verify whether loosing a sense or two has consequences on a spared sensory modality, namely touch, and whether these consequences depend on practice or are biologically determined, we investigated 13 deafblind participants, 16 deaf participants, 15 blind participants, and 13 matched normally sighted and hearing controls on a tactile short-term memory task, using checkerboard matrices of increasing length in which half of the squares were made up of a rough texture and half of a smooth one. Time of execution of a fixed matrix, number of correctly reproduced matrices, largest matrix correctly reproduced and tactile span were recorded. The three groups of sensory-deprived individuals did not differ in any measure, while blind and deaf participants outscored controls in all parameters except time of execution; the difference approached significance for deafblind people compared to controls only in one measure, namely correctly reproduced matrices. In blind and deafblind participants, performance negatively correlated with age of Braille acquisition, the older being the subject when acquiring Braille, the lower the performance, suggesting that practice plays a role. However, the fact that deaf participants, who did not share tactile experience, performed similarly to blind participants and significantly better than controls highlights that practice cannot be the only contribution to better tactile memory.

Tactile massage as a nursing intervention in child and adolescent psychiatry: nurses' experiences.

PubMed

Robertz, A-C; Rudolfsson, G

2016-10-01

WHAT IS KNOWN ABOUT THE SUBJECT?: There is little research on the implementation of tactile massage in child and adolescent psychiatry that describes children's and adolescents' experiences and outcomes. There is also limited knowledge of providing tactile massage in child and adolescent psychiatry. WHAT DOES THIS PAPER ADD TO EXISTING KNOWLEDGE?: This paper describes 10 nurses' experiences of tactile massage as a nursing intervention in child and adolescent psychiatry. The nurses considered tactile massage a non-verbal nursing intervention that could complement other available treatments. It reveals their reflections on the impact of tactile massage on their nursing and on themselves as a person, including the belief that they had developed deepened self-reflection and attentiveness. The nurses highlighted the importance of providing a trusting environment and collaborating with the children and adolescents. They both experienced and observed that tactile massage triggered various physical and mental processes in the children and adolescents, such as improvement in sleep disturbances, an ability to relax in body and mind and a deeper connectedness with their own bodies and feelings. The nurses described instructing next of kin in the use of tactile massage, which they believed could serve as a tool at home, mainly as a way for next of kin to help their children to relax, fall asleep more easily and to deepen connectedness. However, the nurses stressed the need to consider if it was appropriate or desired by the children and adolescents. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Tactile massage addresses the individual's emotional and physiological responses and could therefore bring holistic nursing to child and adolescent psychiatry. It could also help nurses in child and adolescent psychiatry to develop their attentiveness and sensitivity in acknowledging the needs of children and adolescents in psychiatric care. Introduction There is limited research on tactile

An insect-inspired bionic sensor for tactile localization and material classification with state-dependent modulation

PubMed Central

Patanè, Luca; Hellbach, Sven; Krause, André F.; Arena, Paolo; Dürr, Volker

2012-01-01

Insects carry a pair of antennae on their head: multimodal sensory organs that serve a wide range of sensory-guided behaviors. During locomotion, antennae are involved in near-range orientation, for example in detecting, localizing, probing, and negotiating obstacles. Here we present a bionic, active tactile sensing system inspired by insect antennae. It comprises an actuated elastic rod equipped with a terminal acceleration sensor. The measurement principle is based on the analysis of damped harmonic oscillations registered upon contact with an object. The dominant frequency of the oscillation is extracted to determine the distance of the contact point along the probe and basal angular encoders allow tactile localization in a polar coordinate system. Finally, the damping behavior of the registered signal is exploited to determine the most likely material. The tactile sensor is tested in four approaches with increasing neural plausibility: first, we show that peak extraction from the Fourier spectrum is sufficient for tactile localization with position errors below 1%. Also, the damping property of the extracted frequency is used for material classification. Second, we show that the Fourier spectrum can be analysed by an Artificial Neural Network (ANN) which can be trained to decode contact distance and to classify contact materials. Thirdly, we show how efficiency can be improved by band-pass filtering the Fourier spectrum by application of non-negative matrix factorization. This reduces the input dimension by 95% while reducing classification performance by 8% only. Finally, we replace the FFT by an array of spiking neurons with gradually differing resonance properties, such that their spike rate is a function of the input frequency. We show that this network can be applied to detect tactile contact events of a wheeled robot, and how detrimental effects of robot velocity on antennal dynamics can be suppressed by state-dependent modulation of the input signals

Analysis of different vibration patterns to guide blind people.

PubMed

Durá-Gil, Juan V; Bazuelo-Ruiz, Bruno; Moro-Pérez, David; Mollà-Domenech, Fernando

2017-01-01

The literature indicates the best vibration positions and frequencies on the human body where tactile information is transmitted. However, there is a lack of knowledge about how to combine tactile stimuli for navigation. The aim of this study is to compare different vibration patterns outputted to blind people and to determine the most intuitive vibration patterns to indicate direction for navigation purposes through a tactile belt. The vibration patterns that stimulate the front side of the waist are preferred for indicating direction. Vibration patterns applied on the back side of the waist could be suitable for sending messages such as stop.

Short-Term Visual Deprivation, Tactile Acuity, and Haptic Solid Shape Discrimination

PubMed Central

Crabtree, Charles E.; Norman, J. Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task – perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task – the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation. PMID:25397327

Short-term visual deprivation, tactile acuity, and haptic solid shape discrimination.

PubMed

Crabtree, Charles E; Norman, J Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task - perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task - the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation.

Human detection and discrimination of tactile repeatability, mechanical backlash, and temporal delay in a combined tactile-kinesthetic haptic display system.

PubMed

Doxon, Andrew J; Johnson, David E; Tan, Hong Z; Provancher, William R

2013-01-01

Many of the devices used in haptics research are over-engineered for the task and are designed with capabilities that go far beyond human perception levels. Designing devices that more closely match the limits of human perception will make them smaller, less expensive, and more useful. However, many device-centric perception thresholds have yet to be evaluated. To this end, three experiments were conducted, using one degree-of-freedom contact location feedback device in combination with a kinesthetic display, to provide a more explicit set of specifications for similar tactile-kinesthetic haptic devices. The first of these experiments evaluated the ability of humans to repeatedly localize tactile cues across the fingerpad. Subjects could localize cues to within 1.3 mm and showed bias toward the center of the fingerpad. The second experiment evaluated the minimum perceptible difference of backlash at the tactile element. Subjects were able to discriminate device backlash in excess of 0.46 mm on low-curvature models and 0.93 mm on high-curvature models. The last experiment evaluated the minimum perceptible difference of system delay between user action and device reaction. Subjects were able to discriminate delays in excess of 61 ms. The results from these studies can serve as the maximum (i.e., most demanding) device specifications for most tactile-kinesthetic haptic systems.

Peripheral tactile sensory perception of older adults improved using subsensory electrical noise stimulation.

PubMed

Breen, Paul P; Serrador, Jorge M; O'Tuathail, Claire; Quinlan, Leo R; McIntosh, Caroline; ÓLaighin, Gearóid

2016-08-01

Loss of tactile sensory function is common with aging and can lead to numbness and difficulty with balance and gait. In previous work we found that subsensory electrical noise stimulation (SENS) applied to the tibial nerve improved tactile perception in the soles of the feet of healthy adults. In this work we aimed to determine if SENS remained effective in an older adult population with significant levels of sensory loss. Older adult subjects (N=8, female = 4, aged 65-80) had SENS applied via surface electrodes placed proximally to the medial and lateral malleoli. Vibration perception thresholds (VPTs) were assessed in six conditions, two control conditions (no SENS) and four SENS conditions (zero mean ±15µA, 30µA, 45µA and 60µA SD). VPT was assessed at three sites on the plantar aspect of the foot. Vibration perception was significantly improved in the presence of ±30µA SENS and by 16.2±2.4% (mean ± s.e.m.) when optimised for each subject. The improvement in perception was similar across all VPT test sites. Copyright © 2016 IPEM. All rights reserved.

Common mechanisms of spatial attention in memory and perception: a tactile dual-task study.

PubMed

Katus, Tobias; Andersen, Søren K; Müller, Matthias M

2014-03-01

Orienting attention to locations in mnemonic representations engages processes that functionally and anatomically overlap the neural circuitry guiding prospective shifts of spatial attention. The attention-based rehearsal account predicts that the requirement to withdraw attention from a memorized location impairs memory accuracy. In a dual-task study, we simultaneously presented retro-cues and pre-cues to guide spatial attention in short-term memory (STM) and perception, respectively. The spatial direction of each cue was independent of the other. The locations indicated by the combined cues could be compatible (same hand) or incompatible (opposite hands). Incompatible directional cues decreased lateralized activity in brain potentials evoked by visual cues, indicating interference in the generation of prospective attention shifts. The detection of external stimuli at the prospectively cued location was impaired when the memorized location was part of the perceptually ignored hand. The disruption of attention-based rehearsal by means of incompatible pre-cues reduced memory accuracy and affected encoding of tactile test stimuli at the retrospectively cued hand. These findings highlight the functional significance of spatial attention for spatial STM. The bidirectional interactions between both tasks demonstrate that spatial attention is a shared neural resource of a capacity-limited system that regulates information processing in internal and external stimulus representations.

Exploring the Invisible Universe: A Tactile and Braille Exhibit of Astronomical Images

NASA Astrophysics Data System (ADS)

Arcand, K. K.; Watzke, M.; de Pree, C.

2010-06-01

A tactile/Braille exhibit for the visually impaired community in the USA was launched in July 2009. The exhibit is part of the global From Earth to the Universe (FETTU) project, a Cornerstone of the International Year of Astronomy 2009. The science content of the travelling tactile/Braille exhibit includes explanations of our Sun, Eta Carinae, the Crab Nebula, the Whirlpool Galaxy and the electromagnetic spectrum, and was adapted from the tactile/Braille book Touch the Invisible Sky. We present some of the early observations and findings on the tactile/Braille FETTU exhibit. The new exhibit opens a wider door to experiencing and understanding astronomy for the underserved visually impaired population.

Use of tactile feedback to control exploratory movements to characterize object compliance.

PubMed

Su, Zhe; Fishel, Jeremy A; Yamamoto, Tomonori; Loeb, Gerald E

2012-01-01

Humans have been shown to be good at using active touch to perceive subtle differences in compliance. They tend to use highly stereotypical exploratory strategies, such as applying normal force to a surface. We developed similar exploratory and perceptual algorithms for a mechatronic robotic system (Barrett arm/hand system) equipped with liquid-filled, biomimetic tactile sensors (BioTac(®) from SynTouch LLC). The distribution of force on the fingertip was measured by the electrical resistance of the conductive liquid trapped between the elastomeric skin and a cluster of four electrodes on the flat fingertip surface of the rigid core of the BioTac. These signals provided closed-loop control of exploratory movements, while the distribution of skin deformations, measured by more lateral electrodes and by the hydraulic pressure, were used to estimate material properties of objects. With this control algorithm, the robot plus tactile sensor was able to discriminate the relative compliance of various rubber samples.

Tactile display landing safety and precision improvements for the Space Shuttle

NASA Astrophysics Data System (ADS)

Olson, John M.

A tactile display belt using 24 electro-mechanical tactile transducers (tactors) was used to determine if a modified tactile display system, known as the Tactile Situation Awareness System (TSAS) improved the safety and precision of a complex spacecraft (i.e. the Space Shuttle Orbiter) in guided precision approaches and landings. The goal was to determine if tactile cues enhance safety and mission performance through reduced workload, increased situational awareness (SA), and an improved operational capability by increasing secondary cognitive workload capacity and human-machine interface efficiency and effectiveness. Using both qualitative and quantitative measures such as NASA's Justiz Numerical Measure and Synwork1 scores, an Overall Workload (OW) measure, the Cooper-Harper rating scale, and the China Lake Situational Awareness scale, plus Pre- and Post-Flight Surveys, the data show that tactile displays decrease OW, improve SA, counteract fatigue, and provide superior warning and monitoring capacity for dynamic, off-nominal, high concurrent workload scenarios involving complex, cognitive, and multi-sensory critical scenarios. Use of TSAS for maintaining guided precision approaches and landings was generally intuitive, reduced training times, and improved task learning effects. Ultimately, the use of a homogeneous, experienced, and statistically robust population of test pilots demonstrated that the use of tactile displays for Space Shuttle approaches and landings with degraded vehicle systems, weather, and environmental conditions produced substantial improvements in safety, consistency, reliability, and ease of operations under demanding conditions. Recommendations for further analysis and study are provided in order to leverage the results from this research and further explore the potential to reduce the risk of spaceflight and aerospace operations in general.

Establishing Auditory-Tactile-Visual Equivalence Classes in Children with Autism and Developmental Delays

ERIC Educational Resources Information Center

Mullen, Stuart; Dixon, Mark R.; Belisle, Jordan; Stanley, Caleb

2017-01-01

The current study sought to evaluate the efficacy of a stimulus equivalence training procedure in establishing auditory-tactile-visual stimulus classes with 2 children with autism and developmental delays. Participants were exposed to vocal-tactile (A-B) and tactile-picture (B-C) conditional discrimination training and were tested for the…

Tactile Perception in Adults with Autism: A Multidimensional Psychophysical Study

ERIC Educational Resources Information Center

Cascio, Carissa; McGlone, Francis; Folger, Stephen; Tannan, Vinay; Baranek, Grace; Pelphrey, Kevin A.; Essick, Gregory

2008-01-01

Although sensory problems, including unusual tactile sensitivity, are heavily associated with autism, there is a dearth of rigorous psychophysical research. We compared tactile sensation in adults with autism to controls on the palm and forearm, the latter innervated by low-threshold unmyelinated afferents subserving a social/affiliative…

Neuromimetic Event-Based Detection for Closed-Loop Tactile Feedback Control of Upper Limb Prostheses

PubMed Central

Osborn, Luke; Kaliki, Rahul; Soares, Alcimar; Thakor, Nitish

2016-01-01

Upper limb amputees lack the valuable tactile sensing that helps provide context about the surrounding environment. Here we utilize tactile information to provide active touch feedback to a prosthetic hand. First, we developed fingertip tactile sensors for producing biomimetic spiking responses for monitoring contact, release, and slip of an object grasped by a prosthetic hand. We convert the sensor output into pulses, mimicking the rapid and slowly adapting spiking responses of receptor afferents found in the human body. Second, we designed and implemented two neuromimetic event-based algorithms, Compliant Grasping and Slip Prevention, on a prosthesis to create a local closed-loop tactile feedback control system (i.e. tactile information is sent to the prosthesis). Grasping experiments were designed to assess the benefit of this biologically inspired neuromimetic tactile feedback to a prosthesis. Results from able-bodied and amputee subjects show the average number of objects that broke or slipped during grasping decreased by over 50% and the average time to complete a grasping task decreased by at least 10% for most trials when comparing neuromimetic tactile feedback with no feedback on a prosthesis. Our neuromimetic method of closed-loop tactile sensing is a novel approach to improving the function of upper limb prostheses. PMID:27777640

Exploring potential social influences on brain potentials during anticipation of tactile stimulation.

PubMed

Shen, Guannan; Saby, Joni N; Drew, Ashley R; Marshall, Peter J

2017-03-15

This study explored interpersonal influences on electrophysiological responses during the anticipation of tactile stimulation. It is well-known that broad, negative-going potentials are present in the event-related potential (ERP) between a forewarning cue and a tactile stimulus. It has also been shown that the alpha-range mu rhythm shows a lateralized desynchronization over central electrode sites during anticipation of tactile stimulation of the hand. The current study used a tactile discrimination task in which a visual cue signaled that an upcoming stimulus would either be delivered 1500ms later to the participant's hand, to a task partner's hand, or to neither person. For the condition in which participants anticipated the tactile stimulation to their own hand, a negative potential (contingent negative variation, CNV) was observed in the ERP at central sites in the 1000ms prior to the tactile stimulus. Significant mu rhythm desynchronization was also present in the same time window. The magnitudes of the ERPs and of the mu desynchronization were greater in the contralateral than in the ipsilateral hemisphere prior to right hand stimulation. Similar ERP and EEG changes were not present when the visual cue indicated that stimulation would be delivered to the task partner or to neither person. The absence of social influences during anticipation of tactile stimulation, and the relationship between the two brain signatures of anticipatory attention (CNV and mu rhythm) are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation and modification of a commercially available tactile sensor suited for robotic applications. Thesis

NASA Technical Reports Server (NTRS)

Creus, Carolina

1991-01-01

Active (dynamic) tactile sensing was explored using a commercially available tactile array sensor. This task requires the redesign of the sensor interface and a full understanding of the old sensor hardware implementation. There were different stages to this research; the first stage involved the reverse engineering of the old tactile sensor. The second stage had to do with the exploration of the characteristics and behavior of the tactile sensor pad. The next stage dealt with the redesign of the sensor interface using the knowledge gained from the previous two stages. Finally, in the last stage, software to control the tactile sensor was developed to aid in the data acquisition process.

Can Tactile Sensory Processing Differentiate Between Children with Autistic Disorder and Asperger's Disorder?

PubMed Central

2011-01-01

Objective There are debates whether autistic disorder (autism) and Asperger's disorder are two distinct disorders. Moreover, interventional sensory occupational therapy should consider the clinical characteristics of patients. Already, commonalities and differences between Asperger's disorder and autistic disorder are not well studied. The aim of this study is to compare tactile sensory function of children with autistic disorder and children with Asperger's disorder. Methods Tactile sensory function was compared between 36 children with autism and 19 children with Asperger's disorder. The two disorders were diagnosed based on Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision. The parent-reported Tactile Dysfunction Checklist was used to assess the three aspects of hypersensitivity, hyposensitivity, and poor tactile perception and discrimination. Developmental coordination was also assessed. Results Developmental coordination problems total score was not associated with group. The mean (standard deviation) score of tactile hyper-responsivity was not different between the groups. Tactile hyporesponsivity and poor tactile perception and discrimination scores were statistically higher in autistic disorder than Asperger's disorder group. Conclusion These results for the first time indicated that at least some aspects of tactile perception can differentiate these two disorders. Children with autistic disorder have more tactile sensory seeking behaviors than children with Asperger's disorder. Moreover, the ability of children with autistic disorder for tactile discrimination and sensory perception is less than those with Asperger's disorder. Interventional sensory therapy in children with autistic disorder should have some characteristics that can be different and specific for children with Asperger's disorder. Formal intelligence quotient testing was not performed on all of the children evaluated, which is a limitation to this study. In

Market study: Tactile paging system

NASA Technical Reports Server (NTRS)

1977-01-01

A market survey was conducted regarding the commercialization potential and key market factors relevant to a tactile paging system for deaf-blind people. The purpose of the tactile paging system is to communicate to the deaf-blind people in an institutional environment. The system consists of a main console and individual satellite wrist units. The console emits three signals by telemetry to the wrist com (receiving unit) which will measure approximately 2 x 4 x 3/4 inches and will be fastened to the wrist by a strap. The three vibration signals are fire alarm, time period indication, and a third signal which will alert the wearer of the wrist com to the fact that the pin on the top of the wrist is emitting a morse coded message. The Morse code message can be felt and recognized with the finger.

Tactile Functioning in Children Who Are Blind: A Clinical Perspective

ERIC Educational Resources Information Center

Withagen, Ans; Vervloed, Mathijs P. J.; Janssen, Neeltje M.; Knoors, Harry; Verhoeven, Ludo

2010-01-01

This study of 48 children with congenital blindness who attended mainstream schools focused on the tactile and haptic skills they needed in typical academic and everyday tasks. The results showed that, in general, the children mastered such tactile tasks, but some items posed special problems. (Contains 4 tables.)

A Prototype Tactile Sensor Array.

DTIC Science & Technology

1982-09-15

Active Touch Sensing. Technical Report, MIT Artificial Inteligence Laboratory, 1981. (9] Larcombe, M. Carbon Fibre Tactile Sensors. Technical Report...thesis, Carnegie-Mellon University, 1981. [13] Purbrick, John A. A Force Transducer Employing Conductive Silicone Rubber. Technical Report, MIT Artificial

The Effect of Programmable Tactile Displays on Spatial Learning Skills in Children and Adolescents of Different Visual Disability.

PubMed

Leo, Fabrizio; Cocchi, Elena; Brayda, Luca

2017-07-01

Vision loss has severe impacts on physical, social and emotional well-being. The education of blind children poses issues as many scholar disciplines (e.g., geometry, mathematics) are normally taught by heavily relying on vision. Touch-based assistive technologies are potential tools to provide graphical contents to blind users, improving learning possibilities and social inclusion. Raised-lines drawings are still the golden standard, but stimuli cannot be reconfigured or adapted and the blind person constantly requires assistance. Although much research concerns technological development, little work concerned the assessment of programmable tactile graphics, in educative and rehabilitative contexts. Here we designed, on programmable tactile displays, tests aimed at assessing spatial memory skills and shapes recognition abilities. Tests involved a group of blind and a group of low vision children and adolescents in a four-week longitudinal schedule. After establishing subject-specific difficulty levels, we observed a significant enhancement of performance across sessions and for both groups. Learning effects were comparable to raised paper control tests: however, our setup required minimal external assistance. Overall, our results demonstrate that programmable maps are an effective way to display graphical contents in educative/rehabilitative contexts. They can be at least as effective as traditional paper tests yet providing superior flexibility and versatility.

Functional magnetic resonance imaging can be used to explore tactile and nociceptive processing in the infant brain

PubMed Central

Williams, Gemma; Fabrizi, Lorenzo; Meek, Judith; Jackson, Deborah; Tracey, Irene; Robertson, Nicola; Slater, Rebeccah; Fitzgerald, Maria

2015-01-01

Aim Despite the importance of neonatal skin stimulation, little is known about activation of the newborn human infant brain by sensory stimulation of the skin. We carried out functional magnetic resonance imaging (fMRI) to assess the feasibility of measuring brain activation to a range of mechanical stimuli applied to the skin of neonatal infants. Methods We studied 19 term infants with a mean age of 13 days. Brain activation was measured in response to brushing, von Frey hair (vFh) punctate stimulation and, in one case, nontissue damaging pinprick stimulation of the plantar surface of the foot. Initial whole brain analysis was followed by region of interest analysis of specific brain areas. Results Distinct patterns of functional brain activation were evoked by brush and vFh punctate stimulation, which were reduced, but still present, under chloral hydrate sedation. Brain activation increased with increasing stimulus intensity. The feasibility of using pinprick stimulation in fMRI studies was established in one unsedated healthy full-term infant. Conclusion Distinct brain activity patterns can be measured in response to different modalities and intensities of skin sensory stimulation in term infants. This indicates the potential for fMRI studies in exploring tactile and nociceptive processing in the infant brain. PMID:25358870

Populations of striatal medium spiny neurons encode vibrotactile frequency in rats: modulation by slow wave oscillations

PubMed Central

Hawking, Thomas G.

2013-01-01

Dorsolateral striatum (DLS) is implicated in tactile perception and receives strong projections from somatosensory cortex. However, the sensory representations encoded by striatal projection neurons are not well understood. Here we characterized the contribution of DLS to the encoding of vibrotactile information in rats by assessing striatal responses to precise frequency stimuli delivered to a single vibrissa. We applied stimuli in a frequency range (45–90 Hz) that evokes discriminable percepts and carries most of the power of vibrissa vibration elicited by a range of complex fine textures. Both medium spiny neurons and evoked potentials showed tactile responses that were modulated by slow wave oscillations. Furthermore, medium spiny neuron population responses represented stimulus frequency on par with previously reported behavioral benchmarks. Our results suggest that striatum encodes frequency information of vibrotactile stimuli which is dynamically modulated by ongoing brain state. PMID:23114217

Flexible PZT Thin Film Tactile Sensor for Biomedical Monitoring

PubMed Central

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-01-01

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g. PMID:23698262

Flexible PZT thin film tactile sensor for biomedical monitoring.

PubMed

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-04-25

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g.

Tactile-Foot Stimulation Can Assist the Navigation of People with Visual Impairment

PubMed Central

Velázquez, Ramiro; Pissaloux, Edwige; Lay-Ekuakille, Aimé

2015-01-01

Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments. PMID:27019593

Tactile-Foot Stimulation Can Assist the Navigation of People with Visual Impairment.

PubMed

Velázquez, Ramiro; Pissaloux, Edwige; Lay-Ekuakille, Aimé

2015-01-01

Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments.

Effects of inter-stimulus interval and intensity on the perceived urgency of tactile patterns.

PubMed

White, Timothy L; Krausman, Andrea S

2015-05-01

This research examines the feasibility of coding urgency into tactile patterns. Four tactile patterns were presented at either, 12 or 23.5 dB above mean threshold, with an ISI of either 0 (no interval) or 500 msec. Measures included pattern identification and urgency rating on a scale of 1 (least urgent) to 10 (most urgent). Two studies were conducted, a laboratory study and a field study. In the laboratory study, participants received the tactile patterns while seated in front of a computer. For the field study, participants performed dismounted Soldier maneuvers while receiving the tactile patterns. Higher identification rates were found for the 23.5 dB intensity. Patterns presented at the 23.5 dB intensity and no ISI were rated most urgent. No differences in urgency ratings were found for 12 dB based on ISI. Findings support the notion of coding urgency into tactile patterns as a way of augmenting tactile communication. Published by Elsevier Ltd.

Nanowire FET Based Neural Element for Robotic Tactile Sensing Skin

PubMed Central

Taube Navaraj, William; García Núñez, Carlos; Shakthivel, Dhayalan; Vinciguerra, Vincenzo; Labeau, Fabrice; Gregory, Duncan H.; Dahiya, Ravinder

2017-01-01

This paper presents novel Neural Nanowire Field Effect Transistors (υ-NWFETs) based hardware-implementable neural network (HNN) approach for tactile data processing in electronic skin (e-skin). The viability of Si nanowires (NWs) as the active material for υ-NWFETs in HNN is explored through modeling and demonstrated by fabricating the first device. Using υ-NWFETs to realize HNNs is an interesting approach as by printing NWs on large area flexible substrates it will be possible to develop a bendable tactile skin with distributed neural elements (for local data processing, as in biological skin) in the backplane. The modeling and simulation of υ-NWFET based devices show that the overlapping areas between individual gates and the floating gate determines the initial synaptic weights of the neural network - thus validating the working of υ-NWFETs as the building block for HNN. The simulation has been further extended to υ-NWFET based circuits and neuronal computation system and this has been validated by interfacing it with a transparent tactile skin prototype (comprising of 6 × 6 ITO based capacitive tactile sensors array) integrated on the palm of a 3D printed robotic hand. In this regard, a tactile data coding system is presented to detect touch gesture and the direction of touch. Following these simulation studies, a four-gated υ-NWFET is fabricated with Pt/Ti metal stack for gates, source and drain, Ni floating gate, and Al2O3 high-k dielectric layer. The current-voltage characteristics of fabricated υ-NWFET devices confirm the dependence of turn-off voltages on the (synaptic) weight of each gate. The presented υ-NWFET approach is promising for a neuro-robotic tactile sensory system with distributed computing as well as numerous futuristic applications such as prosthetics, and electroceuticals. PMID:28979183

Salience of Tactile Cues: An Examination of Tactor Actuator and Tactile Cue Characteristics

DTIC Science & Technology

2015-08-01

this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense ...patterns of tactile cue arrays, and some differences due to measurement approach. Implications for future research are discussed. 15. SUBJECT TERMS...results for tactor type, taction, and interaction term for the prediction of forced-choice preference ................................................21

Surface texture can bias tactile form perception.

PubMed

Nakatani, Masashi; Howe, Robert D; Tachi, Susumu

2011-01-01

The sense of touch is believed to provide a reliable perception of the object's properties; however, our tactile perceptions could be illusory at times. A recently reported tactile illusion shows that a raised form can be perceived as indented when it is surrounded by textured areas. This phenomenon suggests that the form perception can be influenced by the surface textures in its adjacent areas. As perception of texture and that of form have been studied independently of each other, the present study examined whether textures, in addition to the geometric edges, contribute to the tactile form perception. We examined the perception of the flat and raised contact surface (3.0 mm width) with various heights (0.1, 0.2, 0.3 mm), which had either textured or non-textured adjacent areas, under the static, passive and active touch conditions. Our results showed that texture decreased the raised perception of the surface with a small height (0.1 mm) and decreased the flat perception of the physically flat surface under the passive and active touch conditions. We discuss a possible mechanism underlying the effect of the textures on the form perception based on previous neurophysiological findings.

Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

PubMed

Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

2015-10-01

The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP. Copyright © 2015 the American Physiological Society.

Braille and Tactile Graphics: Youths with Visual Impairments Share Their Experiences

ERIC Educational Resources Information Center

Rosenblum, L. Penny; Herzberg, Tina S.

2015-01-01

Introduction: Data were collected from youths with visual impairment about their experiences with tactile graphics and braille materials used in mathematics and science classes. Methods: Youths answered questions and explored four tactile graphics made using different production methods. They located specific information on each graphic and shared…

Use of early tactile stimulation in rehabilitation of digital nerve injuries.

PubMed

Cheng, A S

2000-01-01

Digital nerves are the most frequently injured peripheral nerve. To improve the recovery of functional sensibility of digital nerve injuries, a prospective randomized controlled study was conducted to see the effect of using early tactile stimulation in rehabilitation of digital nerve injuries. Two specific tactile stimulators were made and prescribed for patients with digital nerve-injury. Twenty-four participants with 32 digital nerve injuries received the prescribed tactile stimulators (experimental group), and another 25 participants with 33 digital nerve injuries received only routine conventional therapy (control group). A significant difference (p < .05) was seen in the experimental group, although there were some variations between the different classes of associated injuries, with least benefit observed in the combined nerve, tendon, and bone injury class. Use of early tactile stimulation as described in this study can be considered an effective way to improve both quality and quantity of recovery of functional sensibility in digital nerve injuries without combined nerve, tendon, and bone injuries.

Robust tactile sensory responses in finger area of primate motor cortex relevant to prosthetic control

NASA Astrophysics Data System (ADS)

Schroeder, Karen E.; Irwin, Zachary T.; Bullard, Autumn J.; Thompson, David E.; Bentley, J. Nicole; Stacey, William C.; Patil, Parag G.; Chestek, Cynthia A.

2017-08-01

Objective. Challenges in improving the performance of dexterous upper-limb brain-machine interfaces (BMIs) have prompted renewed interest in quantifying the amount and type of sensory information naturally encoded in the primary motor cortex (M1). Previous single unit studies in monkeys showed M1 is responsive to tactile stimulation, as well as passive and active movement of the limbs. However, recent work in this area has focused primarily on proprioception. Here we examined instead how tactile somatosensation of the hand and fingers is represented in M1. Approach. We recorded multi- and single units and thresholded neural activity from macaque M1 while gently brushing individual finger pads at 2 Hz. We also recorded broadband neural activity from electrocorticogram (ECoG) grids placed on human motor cortex, while applying the same tactile stimulus. Main results. Units displaying significant differences in firing rates between individual fingers (p  <  0.05) represented up to 76.7% of sorted multiunits across four monkeys. After normalizing by the number of channels with significant motor finger responses, the percentage of electrodes with significant tactile responses was 74.9%  ±  24.7%. No somatotopic organization of finger preference was obvious across cortex, but many units exhibited cosine-like tuning across multiple digits. Sufficient sensory information was present in M1 to correctly decode stimulus position from multiunit activity above chance levels in all monkeys, and also from ECoG gamma power in two human subjects. Significance. These results provide some explanation for difficulties experienced by motor decoders in clinical trials of cortically controlled prosthetic hands, as well as the general problem of disentangling motor and sensory signals in primate motor cortex during dextrous tasks. Additionally, examination of unit tuning during tactile and proprioceptive inputs indicates cells are often tuned differently in different

Neonatal tactile stimulation reverses the effect of neonatal isolation on open-field and anxiety-like behavior, and pain sensitivity in male and female adult Sprague-Dawley rats.

PubMed

Imanaka, A; Morinobu, S; Toki, S; Yamamoto, S; Matsuki, A; Kozuru, T; Yamawaki, S

2008-01-10

It is well known that early life events induce long-lasting psychophysiological and psychobiological influences in later life. In rodent studies, environmental enrichment after weaning prevents the adulthood behavioral and emotional disturbances in response to early adversities. We compared the behavioral effect of neonatal isolation (NI) with the effect of NI accompanied by tactile stimulation (NTS) to determine whether NTS could reverse or prevent the effects of NI on the adulthood behavioral and emotional responses to environmental stimuli. In addition, we also examined the sex difference of the NTS effect. Measurements of body weights, an open-field locomotor test, an elevated plus maze test, a hot-plate test, and a contextual fear-conditioning test were performed on postnatal day 60. As compared with rats subjected to NI, rats subjected to NTS showed significantly higher activity and exploration in the open-field locomotor test, lower anxiety-like behavior in the elevated plus maze test, and significantly prolonged latencies in the hot-plate test, and this effect was equal among males and females. In the contextual fear-conditioning test, whereas NTS significantly reduced the enhanced freezing time due to NI in females, no significant difference in the freezing time between NI and NTS was found in males. These findings indicate that adequate tactile stimulation in early life plays an important role in the prevention of disturbances in the behavioral and emotional responses to environmental stimuli in adulthood induced by early adverse experiences.

Tactile agnosia. Casuistic evidence and theoretical remarks on modality-specific meaning representations and sensorimotor integration.

PubMed

Platz, T

1996-10-01

Somaesthetic, motor and cognitive functions were studied in a man with impaired tactile object-recognition (TOR) in his left hand due to a right parietal convexity meningeoma which had been surgically removed. Primary motor and somatosensory functions were not impaired, and discriminative abilities for various tactile aspects and cognitive skills were preserved. Nevertheless, the patient could often not appreciate the object's nature or significance when it was placed in his left hand and was unable to name or to describe or demonstrate the use of these objects. Therefore, he can be regarded as an example of associative tactile agnosia. The view is taken and elaborated that defective modality-specific meaning representations account for associative tactile agnosia. These meaning representations are conceptualized as learned unimodal feature-entity relationships which are thought to be defective in tactile agnosia. In line with this hypothesis, tactile feature analysis and cross-modal matching of features were largely preserved in the investigated patient, while combining features to form entities was defective in the tactile domain. The alternative hypothesis of agnosia as deficit of cross-modal association of features was not supported. The presumed distributed functional network responsible for TOR is thought to involve perception of features, object recognition and related tactile motor behaviour interactively. A deficit leading primarily to impaired combining features to form entities can therefore be expected to result in additional minor impairment of related perceptual-motor processes. Unilaterality of the gnostic deficit can be explained by a lateralized organization of the functional network responsible for tactile recognition of objects.

Visual enhancing of tactile perception in the posterior parietal cortex.

PubMed

Ro, Tony; Wallace, Ruth; Hagedorn, Judith; Farnè, Alessandro; Pienkos, Elizabeth

2004-01-01

The visual modality typically dominates over our other senses. Here we show that after inducing an extreme conflict in the left hand between vision of touch (present) and the feeling of touch (absent), sensitivity to touch increases for several minutes after the conflict. Transcranial magnetic stimulation of the posterior parietal cortex after this conflict not only eliminated the enduring visual enhancement of touch, but also impaired normal tactile perception. This latter finding demonstrates a direct role of the parietal lobe in modulating tactile perception as a result of the conflict between these senses. These results provide evidence for visual-to-tactile perceptual modulation and demonstrate effects of illusory vision of touch on touch perception through a long-lasting modulatory process in the posterior parietal cortex.

Neurophysiological responses to unpleasant stimuli (acute electrical stimulations and emotional pictures) are increased in patients with schizophrenia

PubMed Central

Duval, Céline Z.; Goumon, Yannick; Kemmel, Véronique; Kornmeier, Jürgen; Dufour, André; Andlauer, Olivier; Vidailhet, Pierre; Poisbeau, Pierrick; Salvat, Eric; Muller, André; Mensah-Nyagan, Ayikoé G.; Schmidt-Mutter, Catherine; Giersch, Anne

2016-01-01

Patients with schizophrenia have often been described as insensitive to nociceptive signals, but objective evidence is sparse. We address this question by combining subjective behavioral and objective neurochemical and neurophysiological measures. The present study involved 21 stabilized and mildly symptomatic patients with schizophrenia and 21 control subjects. We applied electrical stimulations below the pain threshold and assessed sensations of pain and unpleasantness with rating scales, and Somatosensory Evoked Potentials (SEPs/EEG). We also measured attention, two neurochemical stress indices (ACTH/cortisol), and subjective VEPs/EEG responses to visual emotional stimuli. Our results revealed that, subjectively, patients’ evaluations do not differ from controls. However, the amplitude of EEG evoked potentials was greater in patients than controls as early as 50 ms after electrical stimulations and beyond one second after visual processing of emotional pictures. Such responses could not be linked to the stress induced by the stimulations, since stress hormone levels were stable. Nor was there a difference between patients and controls in respect of attention performance and tactile sensitivity. Taken together, all indices measured in patients in our study were either heightened or equivalent relative to healthy volunteers. PMID:26935652

Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

PubMed Central

Zhao, Xuezeng

2017-01-01

The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT) slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as kv and kw, and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities. PMID:29182538

Integration of tactile input across fingers in a patient with finger agnosia.

PubMed

Anema, Helen A; Overvliet, Krista E; Smeets, Jeroen B J; Brenner, Eli; Dijkerman, H Chris

2011-01-01

Finger agnosia has been described as an inability to explicitly individuate between the fingers, which is possibly due to fused neural representations of these fingers. Hence, are patients with finger agnosia unable to keep tactile information perceived over several fingers separate? Here, we tested a finger agnosic patient (GO) on two tasks that measured the ability to keep tactile information simultaneously perceived by individual fingers separate. In experiment 1 GO performed a haptic search task, in which a target (the absence of a protruded line) needed to be identified among distracters (protruded lines). The lines were presented simultaneously to the fingertips of both hands. Similarly to the controls, her reaction time decreased when her fingers were aligned as compared to when her fingers were stretched and in an unaligned position. This suggests that she can keep tactile input from different fingers separate. In experiment two, GO was required to judge the position of a target tactile stimulus to the index finger, relatively to a reference tactile stimulus to the middle finger, both in fingers uncrossed and crossed position. GO was able to indicate the relative position of the target stimulus as well as healthy controls, which indicates that she was able to keep tactile information perceived by two neighbouring fingers separate. Interestingly, GO performed better as compared to the healthy controls in the finger crossed condition. Together, these results suggest the GO is able to implicitly distinguish between tactile information perceived by multiple fingers. We therefore conclude that finger agnosia is not caused by minor disruptions of low-level somatosensory processing. These findings further underpin the idea of a selective impaired higher order body representation restricted to the fingers as underlying cause of finger agnosia. Copyright © 2010 Elsevier Ltd. All rights reserved.

Improved tactile resonance sensor for robotic assisted surgery

NASA Astrophysics Data System (ADS)

Oliva Uribe, David; Schoukens, Johan; Stroop, Ralf

2018-01-01

This paper presents an improved tactile sensor using a piezoelectric bimorph able to differentiate soft materials with similar mechanical characteristics. The final aim is to develop intelligent surgical tools for brain tumour resection using integrated sensors in order to improve tissue tumour delineation and tissue differentiation. The bimorph sensor is driven using a random phase multisine and the properties of contact between the sensor's tip and a certain load are evaluated by means of the evaluation of the nonparametric FRF. An analysis of the nonlinear contributions is presented to show that the use of a linear model is feasible for the measurement conditions. A series of gelatine phantoms were tested. The tactile sensor is able to identify minimal differences in the consistency of the measured samples considering viscoelastic behaviour. A variance analysis was performed to evaluate the reliability of the sensors and to identify possible error sources due to inconsistencies in the preparation method of the phantoms. The results of the variance analysis are discussed showing that ability of the proposed tactile sensor to perform high quality measurements.

Tactile sensitivity of gloved hands in the cold operation.

PubMed

Geng, Q; Kuklane, K; Holmér, I

1997-11-01

In this study, tactile sensitivity of gloved hand in the cold operation has been investigated. The relations among physical properties of protective gloves and hand tactile sensitivity and cold protection were also analysed both objectively and subjectively. Subjects with various gloves participated in the experimental study during cold exposure at different ambient temperatures of -12 degrees C and -25 degrees C. Tactual performance was measured using an identification task with various sizes of objects over the percentage of misjudgment. Forearm, hand and finger skin temperatures were also recorded throughout. The experimental data were analysed using analysis of variance (ANOVA) model and the Tukey's multiple range test. The results obtained indicated that the tactual performance was affected both by gloves and by hands/fingers cooling. Effect of object size on the tactile discrimination was significant and the misjudgment increased when similar sizes of objects were identified, especially at -25 degrees C.

Tactile perceptual learning: learning curves and transfer to the contralateral finger.

PubMed

Kaas, Amanda L; van de Ven, Vincent; Reithler, Joel; Goebel, Rainer

2013-02-01

Tactile perceptual learning has been shown to improve performance on tactile tasks, but there is no agreement about the extent of transfer to untrained skin locations. The lack of such transfer is often seen as a behavioral index of the contribution of early somatosensory brain regions. Moreover, the time course of improvements has never been described explicitly. Sixteen subjects were trained on the Ludvigh task (a tactile vernier task) on four subsequent days. On the fifth day, transfer of learning to the non-trained contralateral hand was tested. In five subjects, we explored to what extent training effects were retained approximately 1.5 years after the final training session, expecting to find long-term retention of learning effects after training. Results showed that tactile perceptual learning mainly occurred offline, between sessions. Training effects did not transfer initially, but became fully available to the untrained contralateral hand after a few additional training runs. After 1.5 years, training effects were not fully washed out and could be recuperated within a single training session. Interpreted in the light of theories of visual perceptual learning, these results suggest that tactile perceptual learning is not fundamentally different from visual perceptual learning, but might proceed at a slower pace due to procedural and task differences, thus explaining the apparent divergence in the amount of transfer and long-term retention.

Maternal and littermate deprivation disrupts maternal behavior and social-learning of food preference in adulthood: tactile stimulation, nest odor, and social rearing prevent these effects.

PubMed

Melo, Angel I; Lovic, Vedran; Gonzalez, Andrea; Madden, Melissa; Sinopoli, Katia; Fleming, Alison S

2006-04-01

Maternal and littermate (social) separation, through artificial rearing (AR), disrupts the development of subsequent maternal behavior and social learning in rats. The addition of maternal-licking-like stimulation during AR, partially reverses some of these effects. However, little is know about the role of social stimuli from littermates and nest odors during the preweaning period, in the development of the adult maternal behavior and social learning. The purpose of this study was to examine the effects of peer- and peer-and-odor rearing on the development of maternal behavior and social learning in rats. Female pups were reared with mothers (mother reared-MR) or without mothers (AR) from postnatal day (PND) 3. AR rats received three different treatments: (1) AR-CONTROL group received minimal tactile stimulation, (2) AR-ODOR females received exposure to maternal nest material inside the AR-isolation-cup environment, (3) AR-SOCIAL group was reared in the cup with maternal nest material and a conspecific of the same-age and same-sex and received additional tactile stimulation. MR females were reared by their mothers in the nest and with conspecifics. In adulthood, rats were tested for maternal behavior towards their own pups and in a social learning task. Results confirm our previous report that AR impairs performance of maternal behavior and the development of a social food preference. Furthermore, social cues from a littermate, in combination with tactile stimulation and the nest odor, reversed the negative effects of complete isolation (AR-CONTROL) on some of the above behaviors. Exposure to the odor alone also had effects on some of these olfactory-mediated behaviors. These studies indicate that social stimulation from littermates during the preweaning period, in combination with odor from the nest and tactile stimulation, contributes to the development of affiliative behaviors. Copyright (c) 2006 Wiley Periodicals, Inc.

The tactile movement aftereffect.

PubMed

Hollins, M; Favorov, O

1994-01-01

The existence of a tactile movement aftereffect was established in a series of experiments on the palmar surface of the hand and fingers of psychophysical observers. During adaptation, observers cupped their hand around a moving drum for up to 3 min; following this period of stimulation, they typically reported an aftereffect consisting of movement sensations located on and deep to the skin, and lasting for up to 1 min. Preliminary experiments comparing a number of stimulus materials mounted on the drum demonstrated that a surface approximating a low-spatial-frequency square wave, with a smooth microtexture, was especially effective at inducing the aftereffect; this adapting stimulus was therefore used throughout the two main experiments. In Experiment 1, the vividness of the aftereffect produced by 2 min of adaptation was determined under three test conditions: with the hand (1) remaining on the now stationary drum; (2) in contact with a soft, textured surface; or (3) suspended in air. Subjects' free magnitude estimates of the peak vividness of the aftereffect were not significantly different across conditions; each subject experienced the aftereffect at least once under each condition. Thus the tactile movement aftereffect does not seem to depend critically on the ponditions of stimulation that obtain while it is being experienced. In Experiment 2, the vividness and duration of the aftereffect were measured as a function of the duration of the adapting stimulus. Both measures increased steadily over the range of durations explored (30-180 sec). In its dependence on adapting duration, the aftereffect resembles the waterfall illusion in vision. An explanation for the tactile movement aftereffect is proposed, based on the model of cortical dynamics of Whitsel et al. (1989, 1991). With assumed modest variation of one parameter across individuals, this application of the model is able to account both for the data of the majority of subjects, who experienced the

Pure Amorphagnosia without Tactile Object Agnosia.

PubMed

Kubota, Shinichirou; Yamada, Mai; Satoh, Hideyo; Satoh, Akira; Tsujihata, Mitsuhiro

2017-01-01

A 54-year-old female showed amorphagnosia without ahylognosia and tactile agnosia 40 days after the onset of right cerebral infarction. Her basic somatosensory functions were normal. The appreciation of substance qualities (hylognosia) was preserved, but the patient's inability to recognize the size and shape (morphagnosia) was confined to 2- and 3-dimensional shapes (amorphagnosia) in the left hand. However, the patient's ability to recognize real daily objects was well preserved. Brain MRI after admission showed ischemic lesions confined to the right pre- and postcentral gyri and the medial frontal cortex on DWI and FLAIR images. An analysis of SPECT images revealed that the most decreased areas were localized to the pre- and postcentral gyri, superior and inferior parietal lobules, supramarginal gyrus, and angular gyrus. Considering the previous reported cases, the responsible lesion for the impaired perception of hylognosia and morphagnosia may not necessarily be confined to the right hemisphere. To date, 5 reports (6 cases) of tactile agnosia have been published; 4 cases presented with both ahylognosia and amorphagnosia, while 1 presented with only amorphagnosia, and another showed amorphagnosia and mild ahylognosia. Our case is the first to present with only amorphagnosia without tactile agnosia. The mechanism for the well-preserved recognition of real objects may depend on the preserved hylognosia. Of note, there have been no reports showing only ahylognosia without amorphagnosia. Further studies are necessary to clarify whether or not patients with preserved hylognosia or morphagnosia retain the ability to perceive real objects.

Evaluation of Persons of Varying Ages.

ERIC Educational Resources Information Center

Stolte, John F.

1996-01-01

Reviews two experiments that strongly support dual coding theory. Dual coding theory holds that communicating concretely (tactile, auditory, or visual stimuli) affects evaluative thinking stronger than communicating abstractly through words and numbers. The experiments applied this theory to the realm of age and evaluation. (MJP)

Left hand tactile agnosia after posterior callosal lesion.

PubMed

Balsamo, Maddalena; Trojano, Luigi; Giamundo, Arcangelo; Grossi, Dario

2008-09-01

We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.

Refreshable tactile displays based on bistable electroactive polymer

NASA Astrophysics Data System (ADS)

Niu, Xiaofan; Brochu, Paul; Salazar, Brandon; Pei, Qibing

2011-04-01

Refreshable tactile displays can significantly improve the education of blind children and the quality of life of people with severe vision impairment. A number of actuator technologies have been investigated. Bistable Electroactive Polymer (BSEP) appears to be well suited for this application. The BSEP exhibits a bistable electrically actuated strain as large as 335%. We present improved refreshable tactile display devices fabricated on thin plastic sheets. Stacked BSEP films were employed to meet the requirements in raised dot height and supporting force. The bistable nature of the actuation reduces the power consumption and simplifies the device operation.

Effect of tactile vibration on annoyance to synthesized propfan noise

NASA Technical Reports Server (NTRS)

Clevenson, S. A.

1981-01-01

Design information that maximizes passenger comfort for propfan aircraft is presented. Predicted noise and vibration environments and the resultant passenger acceptability were studied. The effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions was analyzed. Passenger reactions to a wide range of noise with and without tactile vibration was studied. The passenger ride quality simulator was employed using subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80-100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50-200 Hz), two harmonic rolloffs, and three tone/noise ratios. It is indicated that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.

Tactile-Sensing Based on Flexible PVDF Nanofibers via Electrospinning: A Review

PubMed Central

Wang, Xiaomei; Sun, Fazhe; Yin, Guangchao; Wang, Yuting; Liu, Bo

2018-01-01

The flexible tactile sensor has attracted widespread attention because of its great flexibility, high sensitivity, and large workable range. It can be integrated into clothing, electronic skin, or mounted on to human skin. Various nanostructured materials and nanocomposites with high flexibility and electrical performance have been widely utilized as functional materials in flexible tactile sensors. Polymer nanomaterials, representing the most promising materials, especially polyvinylidene fluoride (PVDF), PVDF co-polymer and their nanocomposites with ultra-sensitivity, high deformability, outstanding chemical resistance, high thermal stability and low permittivity, can meet the flexibility requirements for dynamic tactile sensing in wearable electronics. Electrospinning has been recognized as an excellent straightforward and versatile technique for preparing nanofiber materials. This review will present a brief overview of the recent advances in PVDF nanofibers by electrospinning for flexible tactile sensor applications. PVDF, PVDF co-polymers and their nanocomposites have been successfully formed as ultrafine nanofibers, even as randomly oriented PVDF nanofibers by electrospinning. These nanofibers used as the functional layers in flexible tactile sensors have been reviewed briefly in this paper. The β-phase content, which is the strongest polar moment contributing to piezoelectric properties among all the crystalline phases of PVDF, can be improved by adjusting the technical parameters in electrospun PVDF process. The piezoelectric properties and the sensibility for the pressure sensor are improved greatly when the PVDF fibers become more oriented. The tactile performance of PVDF composite nanofibers can be further promoted by doping with nanofillers and nanoclay. Electrospun P(VDF-TrFE) nanofiber mats used for the 3D pressure sensor achieved excellent sensitivity, even at 0.1 Pa. The most significant enhancement is that the aligned electrospun core-shell P

A new dynamic tactile display for reconfigurable braille: implementation and tests.

PubMed

Motto Ros, Paolo; Dante, Vittorio; Mesin, Luca; Petetti, Erminio; Del Giudice, Paolo; Pasero, Eros

2014-01-01

Different tactile interfaces have been proposed to represent either text (braille) or, in a few cases, tactile large-area screens as replacements for visual displays. None of the implementations so far can be customized to match users' preferences, perceptual differences and skills. Optimal choices in these respects are still debated; we approach a solution by designing a flexible device allowing the user to choose key parameters of tactile transduction. We present here a new dynamic tactile display, a 8 × 8 matrix of plastic pins based on well-established and reliable piezoelectric technology to offer high resolution (pin gap 0.7mm) as well as tunable strength of the pins displacement, and refresh rate up to 50s(-1). It can reproduce arbitrary patterns, allowing it to serve the dual purpose of providing, depending on contingent user needs, tactile rendering of non-character information, and reconfigurable braille rendering. Given the relevance of the latter functionality for the expected average user, we considered testing braille encoding by volunteers a benchmark of primary importance. Tests were performed to assess the acceptance and usability with minimal training, and to check whether the offered flexibility was indeed perceived by the subject as an added value compared to conventional braille devices. Different mappings between braille dots and actual tactile pins were implemented to match user needs. Performances of eight experienced braille readers were defined as the fraction of correct identifications of rendered content. Different information contents were tested (median performance on random strings, words, sentences identification was about 75%, 85%, 98%, respectively, with a significant increase, p < 0.01), obtaining statistically significant improvements in performance during the tests (p < 0.05). Experimental results, together with qualitative ratings provided by the subjects, show a good acceptance and the effectiveness of the proposed solution.

A new dynamic tactile display for reconfigurable braille: implementation and tests

PubMed Central

Motto Ros, Paolo; Dante, Vittorio; Mesin, Luca; Petetti, Erminio; Del Giudice, Paolo; Pasero, Eros

2014-01-01

Different tactile interfaces have been proposed to represent either text (braille) or, in a few cases, tactile large-area screens as replacements for visual displays. None of the implementations so far can be customized to match users' preferences, perceptual differences and skills. Optimal choices in these respects are still debated; we approach a solution by designing a flexible device allowing the user to choose key parameters of tactile transduction. We present here a new dynamic tactile display, a 8 × 8 matrix of plastic pins based on well-established and reliable piezoelectric technology to offer high resolution (pin gap 0.7mm) as well as tunable strength of the pins displacement, and refresh rate up to 50s−1. It can reproduce arbitrary patterns, allowing it to serve the dual purpose of providing, depending on contingent user needs, tactile rendering of non-character information, and reconfigurable braille rendering. Given the relevance of the latter functionality for the expected average user, we considered testing braille encoding by volunteers a benchmark of primary importance. Tests were performed to assess the acceptance and usability with minimal training, and to check whether the offered flexibility was indeed perceived by the subject as an added value compared to conventional braille devices. Different mappings between braille dots and actual tactile pins were implemented to match user needs. Performances of eight experienced braille readers were defined as the fraction of correct identifications of rendered content. Different information contents were tested (median performance on random strings, words, sentences identification was about 75%, 85%, 98%, respectively, with a significant increase, p < 0.01), obtaining statistically significant improvements in performance during the tests (p < 0.05). Experimental results, together with qualitative ratings provided by the subjects, show a good acceptance and the effectiveness of the proposed solution

GelSight: High-Resolution Robot Tactile Sensors for Estimating Geometry and Force

PubMed Central

Yuan, Wenzhen; Dong, Siyuan; Adelson, Edward H.

2017-01-01

Tactile sensing is an important perception mode for robots, but the existing tactile technologies have multiple limitations. What kind of tactile information robots need, and how to use the information, remain open questions. We believe a soft sensor surface and high-resolution sensing of geometry should be important components of a competent tactile sensor. In this paper, we discuss the development of a vision-based optical tactile sensor, GelSight. Unlike the traditional tactile sensors which measure contact force, GelSight basically measures geometry, with very high spatial resolution. The sensor has a contact surface of soft elastomer, and it directly measures its deformation, both vertical and lateral, which corresponds to the exact object shape and the tension on the contact surface. The contact force, and slip can be inferred from the sensor’s deformation as well. Particularly, we focus on the hardware and software that support GelSight’s application on robot hands. This paper reviews the development of GelSight, with the emphasis in the sensing principle and sensor design. We introduce the design of the sensor’s optical system, the algorithm for shape, force and slip measurement, and the hardware designs and fabrication of different sensor versions. We also show the experimental evaluation on the GelSight’s performance on geometry and force measurement. With the high-resolution measurement of shape and contact force, the sensor has successfully assisted multiple robotic tasks, including material perception or recognition and in-hand localization for robot manipulation. PMID:29186053

An invisible touch: Body-related multisensory conflicts modulate visual consciousness.

PubMed

Salomon, Roy; Galli, Giulia; Łukowska, Marta; Faivre, Nathan; Ruiz, Javier Bello; Blanke, Olaf

2016-07-29

The majority of scientific studies on consciousness have focused on vision, exploring the cognitive and neural mechanisms of conscious access to visual stimuli. In parallel, studies on bodily consciousness have revealed that bodily (i.e. tactile, proprioceptive, visceral, vestibular) signals are the basis for the sense of self. However, the role of bodily signals in the formation of visual consciousness is not well understood. Here we investigated how body-related visuo-tactile stimulation modulates conscious access to visual stimuli. We used a robotic platform to apply controlled tactile stimulation to the participants' back while they viewed a dot moving either in synchrony or asynchrony with the touch on their back. Critically, the dot was rendered invisible through continuous flash suppression. Manipulating the visual context by presenting the dot moving on either a body form, or a non-bodily object we show that: (i) conflict induced by synchronous visuo-tactile stimulation in a body context is associated with a delayed conscious access compared to asynchronous visuo-tactile stimulation, (ii) this effect occurs only in the context of a visual body form, and (iii) is not due to detection or response biases. The results indicate that body-related visuo-tactile conflicts impact visual consciousness by facilitating access of non-conflicting visual information to awareness, and that these are sensitive to the visual context in which they are presented, highlighting the interplay between bodily signals and visual experience. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acoustic Tactile Representation of Visual Information

NASA Astrophysics Data System (ADS)

Silva, Pubudu Madhawa

Our goal is to explore the use of hearing and touch to convey graphical and pictorial information to visually impaired people. Our focus is on dynamic, interactive display of visual information using existing, widely available devices, such as smart phones and tablets with touch sensitive screens. We propose a new approach for acoustic-tactile representation of visual signals that can be implemented on a touch screen and allows the user to actively explore a two-dimensional layout consisting of one or more objects with a finger or a stylus while listening to auditory feedback via stereo headphones. The proposed approach is acoustic-tactile because sound is used as the primary source of information for object localization and identification, while touch is used for pointing and kinesthetic feedback. A static overlay of raised-dot tactile patterns can also be added. A key distinguishing feature of the proposed approach is the use of spatial sound (directional and distance cues) to facilitate the active exploration of the layout. We consider a variety of configurations for acoustic-tactile rendering of object size, shape, identity, and location, as well as for the overall perception of simple layouts and scenes. While our primary goal is to explore the fundamental capabilities and limitations of representing visual information in acoustic-tactile form, we also consider a number of relatively simple configurations that can be tied to specific applications. In particular, we consider a simple scene layout consisting of objects in a linear arrangement, each with a distinct tapping sound, which we compare to a ''virtual cane.'' We will also present a configuration that can convey a ''Venn diagram.'' We present systematic subjective experiments to evaluate the effectiveness of the proposed display for shape perception, object identification and localization, and 2-D layout perception, as well as the applications. Our experiments were conducted with visually blocked

Achilles' ear? Inferior human short-term and recognition memory in the auditory modality.

PubMed

Bigelow, James; Poremba, Amy

2014-01-01

Studies of the memory capabilities of nonhuman primates have consistently revealed a relative weakness for auditory compared to visual or tactile stimuli: extensive training is required to learn auditory memory tasks, and subjects are only capable of retaining acoustic information for a brief period of time. Whether a parallel deficit exists in human auditory memory remains an outstanding question. In the current study, a short-term memory paradigm was used to test human subjects' retention of simple auditory, visual, and tactile stimuli that were carefully equated in terms of discriminability, stimulus exposure time, and temporal dynamics. Mean accuracy did not differ significantly among sensory modalities at very short retention intervals (1-4 s). However, at longer retention intervals (8-32 s), accuracy for auditory stimuli fell substantially below that observed for visual and tactile stimuli. In the interest of extending the ecological validity of these findings, a second experiment tested recognition memory for complex, naturalistic stimuli that would likely be encountered in everyday life. Subjects were able to identify all stimuli when retention was not required, however, recognition accuracy following a delay period was again inferior for auditory compared to visual and tactile stimuli. Thus, the outcomes of both experiments provide a human parallel to the pattern of results observed in nonhuman primates. The results are interpreted in light of neuropsychological data from nonhuman primates, which suggest a difference in the degree to which auditory, visual, and tactile memory are mediated by the perirhinal and entorhinal cortices.

Tactile pavement for guiding walking direction: An assessment of heading direction and gait stability.

PubMed

Pluijter, Nanda; de Wit, Lieke P W; Bruijn, Sjoerd M; Plaisier, Myrthe A

2015-10-01

For maintaining heading direction while walking we heavily rely on vision. Therefore, walking in the absence of vision or with visual attention directed elsewhere potentially leads to dangerous situations. Here we investigated whether tactile information from the feet can be used as a (partial) substitute for vision in maintaining a stable heading direction. If so, participants should be better able to keep a constant heading direction on tactile pavement that indicates directionality than on regular flat pavement. However, such a pavement may also be destabilizing. Thus we asked participants to walk straight ahead on regular pavement, and on tactile pavement (tiles with ridges along the walking direction) while varying the amount of vision. We assessed the effects of the type of pavement as well as the amount of vision on the variability of the heading direction as well as gait stability. Both of these measures were calculated from accelerations and angular velocities recorded from a smartphone attached to the participants trunk. Results showed that on tactile pavement participants had a less variations in their heading direction than on regular pavement. The drawback, however, was that the tactile pavement used in this study decreased gait stability. In sum, tactile pavement can be used as a partial substitute for vision in maintaining heading direction, but it can also decrease gait stability. Future work should focus on designing tactile pavement that does provided directional clues, but is less destabilizing. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of haptic based piezoresistive artificial fingertip: Toward efficient tactile sensing systems for humanoids.

PubMed

TermehYousefi, Amin; Azhari, Saman; Khajeh, Amin; Hamidon, Mohd Nizar; Tanaka, Hirofumi

2017-08-01

Haptic sensors are essential devices that facilitate human-like sensing systems such as implantable medical devices and humanoid robots. The availability of conducting thin films with haptic properties could lead to the development of tactile sensing systems that stretch reversibly, sense pressure (not just touch), and integrate with collapsible. In this study, a nanocomposite based hemispherical artificial fingertip fabricated to enhance the tactile sensing systems of humanoid robots. To validate the hypothesis, proposed method was used in the robot-like finger system to classify the ripe and unripe tomato by recording the metabolic growth of the tomato as a function of resistivity change during a controlled indention force. Prior to fabrication, a finite element modeling (FEM) was investigated for tomato to obtain the stress distribution and failure point of tomato by applying different external loads. Then, the extracted computational analysis information was utilized to design and fabricate nanocomposite based artificial fingertip to examine the maturity analysis of tomato. The obtained results demonstrate that the fabricated conformable and scalable artificial fingertip shows different electrical property for ripe and unripe tomato. The artificial fingertip is compatible with the development of brain-like systems for artificial skin by obtaining periodic response during an applied load. Copyright © 2017. Published by Elsevier B.V.

Artery cross-clamping during laparoscopic vascular surgeries; a computational tactile sensing approach.

PubMed

Pahlavan, Pedram; Najarian, Siamak; Afshari, Elnaz; Moini, Majid

2013-01-01

Artificial palpation is one of the most valuable achievements of artificial tactile sensing approach that can be used in various fields of medicine and more specifically in surgery. These techniques cause different surgical maneuvers to be done more precisely and noninvasively. In this study, considering the present problems and limitations of cross-clamping an artery during laparoscopic vascular surgeries, a new tactile sensory system will be introduced.Having imitated surgeon's palpation during open vascular surgeries and modeled it conceptually, the optimal amount of the total angular displacement of each robot joint in order to cross-clamping an artery without damaging to the artery surrounding tissues will be calculated. The elastic governing equation of contact occurred between the tactile sensor placed on the first link of the robot and the surrounding tissues around the artery were developed. A finite element model is coupled with genetic algorithm optimization method so that the normal stress and displacements in contact surface of the robot and artery's surrounding tissues would be minimized. Thus, reliability and accuracy of artificial tactile sensing method in artery cross-clamping will be demonstrated. Finally, the functional principles of the new tactile system capable of cross-clamping an artery during laparoscopic surgeries will be presented.

Electro-tactile stimulation of the posterior neck induces body anteropulsion during upright stance.

PubMed

De Nunzio, A M; Yavuz, U S; Martinez-Valdes, E; Farina, D; Falla, D

2018-05-01

Sensory information conveyed along afferent fibers from muscle and joint proprioceptors play an important role in the control of posture and gait in humans. In particular, proprioceptive information from the neck is fundamental in supplying the central nervous system with information about the orientation and movement of the head relative to the rest of the body. The previous studies have confirmed that proprioceptive afferences originating from the neck region, evoked via muscle vibration, lead to strong body-orienting effects during static conditions (e.g., leaning of the body forwards or backwards, depending on location of vibration). However, it is not yet certain in humans, whether the somatosensory receptors located in the deep skin (cutaneous mechanoreceptors) have a substantive contribution to postural control, as vibratory stimulation encompasses the receptive field of all the somatosensory receptors from the skin to the muscles. The aim of this study was to investigate the postural effect of cutaneous mechanoreceptor afferences using electro-tactile stimulation applied to the neck. Ten healthy volunteers (8M, 2F) were evaluated. The average position of their centre of foot pressure (CoP) was acquired before, during, and after a subtle electro-tactile stimulation over their posterior neck (mean ± SD = 5.1 ± 2.3 mA at 100 Hz-140% of the perception threshold) during upright stance with their eyes closed. The electro-tactile stimulation led to a body-orienting effect with the subjects consistently leaning forward. An average shift of the CoP of 12.1 ± 11.9 mm (mean ± SD) was reported, which significantly (p < 0.05) differed from its average position under a control condition (no stimulation). These results indicate that cutaneous mechanoreceptive inflow from the neck is integrated to control stance. The findings are relevant for the exploitation of electro-tactile stimulation for rehabilitation interventions where induced

Stimuli-Responsive DNA-Based Hydrogels: From Basic Principles to Applications.

PubMed

Kahn, Jason S; Hu, Yuwei; Willner, Itamar

2017-04-18

The base sequence of nucleic acids encodes structural and functional information into the DNA biopolymer. External stimuli such as metal ions, pH, light, or added nucleic acid fuel strands provide triggers to reversibly switch nucleic acid structures such as metal-ion-bridged duplexes, i-motifs, triplex nucleic acids, G-quadruplexes, or programmed double-stranded hybrids of oligonucleotides (DNA). The signal-triggered oligonucleotide structures have been broadly applied to develop switchable DNA nanostructures and DNA machines, and these stimuli-responsive assemblies provide functional scaffolds for the rapidly developing area of DNA nanotechnology. Stimuli-responsive hydrogels undergoing signal-triggered hydrogel-to-solution transitions or signal-controlled stiffness changes attract substantial interest as functional matrices for controlled drug delivery, materials exhibiting switchable mechanical properties, acting as valves or actuators, and "smart" materials for sensing and information processing. The integration of stimuli-responsive oligonucleotides with hydrogel-forming polymers provides versatile means to exploit the functional information encoded in the nucleic acid sequences to yield stimuli-responsive hydrogels exhibiting switchable physical, structural, and chemical properties. Stimuli-responsive DNA-based nucleic acid structures are integrated in acrylamide polymer chains and reversible, switchable hydrogel-to-solution transitions of the systems are demonstrated by applying external triggers, such as metal ions, pH-responsive strands, G-quadruplex, and appropriate counter triggers that bridge and dissociate the polymer chains. By combining stimuli-responsive nucleic acid bridges with thermosensitive poly(N-isopropylacrylamide) (pNIPAM) chains, systems undergoing reversible solution ↔ hydrogel ↔ solid transitions are demonstrated. Specifically, by bridging acrylamide polymer chains by two nucleic acid functionalities, where one type of bridging unit

Lateralized ultradian rhythms: evidence from tactile discrimination of either hand.

PubMed

Meier-Koll, A

1998-12-01

Endogenous ultradian rhythms with periods of one or a few hours affect not only on physiological and behavioural functions but also perception and cognition. In particular, lateralized ultradian rhythms which seem to operate separately in the right and left hemispheres of the brain can be monitored by testing the tactile discrimination of the contralateral hand. The present paper is based on two subsequent studies: First, ultradian rhythms in tactile discrimination of either hand were examined in German subjects under laboratory conditions. Considerably different ultradian periods of right and left-handed tactile error rate were found in men but not in women. In a second study, a group of Kenyan Masai shepherds were tested while the subjects were leading herds on daily feeding routes through a savanna habitat. They showed ultradian periods of about 2 hours in tactile discrimination of either hand. Since the right hemisphere is specialized for visuospatial, the left for verbal processing lateralized ultradian rhythms may serve for a long-scale timing of neural processes underlying spatial and semantic mapping of the environment. Sex difference in German subjects and lateral differences found in left-handed (right-hemispheric) ultradian rhythms of German and Masai subjects are discussed from this point of view.

Making your skin crawl: The role of tactile sensitivity in disease avoidance.

PubMed

Hunt, David Francis; Cannell, Grace; Davenhill, Nicholas A; Horsford, Stephanie A; Fleischman, Diana S; Park, Justin H

2017-07-01

Mounting evidence indicates that animals, including humans, have evolved a behavioral disease-avoidance system designed to facilitate the detection and avoidance of sources of pathogens, and that this system interacts with physiological defenses. The skin acts as an important anatomical barrier, yet little research has investigated the role of tactile sensitivity in disease avoidance. Increased tactile sensitivity in the presence of potential sources of pathogens may facilitate prophylactic behaviors such as self-grooming. Across multiple studies, we tested the hypothesis that the induction of disgust-the key emotion underlying disease avoidance-may lead to greater tactile sensitivity compared to control conditions. A nonsignificant trend was found in a pilot study, which was replicated (and found to be significant) in Studies 1 and 2. To our knowledge, these results are the first to demonstrate disgust-induced changes in tactile sensitivity, and they contribute to the growing literature on the integrated evolved defenses against infectious disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Differing ERP patterns caused by suction and puff stimuli.

PubMed

Choi, Mi-Hyun; Kim, Hyung-Sik; Baek, Ji-Hye; Lee, Jung-Chul; Park, Sung-Jun; Jeong, Ul-Ho; Gim, Seon-Young; You, Ji Hye; Kim, Sung-Pil; Lim, Dae-Woon; Kim, Hyun-Jun; Chung, Soon-Cheol

2015-05-06

The present study compared event-related potential (ERP) patterns for two stimuli types, puff and suction, by applying these stimuli to the fingers; ERP patterns for the two stimuli were compared at C3, an area related to somatosensory perception, and at FC5, an area related to motor function. Participants were 12 healthy males in their 20s (mean age=23.1±2.0 years). One session consisted of a Control Phase (3s), a Stimulation Phase (3s), and a Rest Phase (9s). During the Stimulation Phase, a 4-psi suction or puff stimulus was applied to the first joint of the right index finger. After completion of the session, a subjective magnitude test was presented. In all phases, electroencephalography signals were recorded. We extracted maximum positive amplitude and minimum negative amplitude as well as relevant latency values for C3 and FC5 signals. Suction and puff stimuli had similar subjective magnitude scores. For both C3 and FC5, the maximum and minimum amplitude latency was reached earlier for the suction stimulus than for the puff stimulus. In conclusion, when suction and puff stimuli of the same intensity were applied to the fingers, the suction stimulus caused a more sensitive response in the somatosensory area (C3) and motor area (FC5) than did the puff stimulus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Pure Amorphagnosia without Tactile Object Agnosia

PubMed Central

Kubota, Shinichirou; Yamada, Mai; Satoh, Hideyo; Satoh, Akira; Tsujihata, Mitsuhiro

2017-01-01

A 54-year-old female showed amorphagnosia without ahylognosia and tactile agnosia 40 days after the onset of right cerebral infarction. Her basic somatosensory functions were normal. The appreciation of substance qualities (hylognosia) was preserved, but the patient's inability to recognize the size and shape (morphagnosia) was confined to 2- and 3-dimensional shapes (amorphagnosia) in the left hand. However, the patient's ability to recognize real daily objects was well preserved. Brain MRI after admission showed ischemic lesions confined to the right pre- and postcentral gyri and the medial frontal cortex on DWI and FLAIR images. An analysis of SPECT images revealed that the most decreased areas were localized to the pre- and postcentral gyri, superior and inferior parietal lobules, supramarginal gyrus, and angular gyrus. Considering the previous reported cases, the responsible lesion for the impaired perception of hylognosia and morphagnosia may not necessarily be confined to the right hemisphere. To date, 5 reports (6 cases) of tactile agnosia have been published; 4 cases presented with both ahylognosia and amorphagnosia, while 1 presented with only amorphagnosia, and another showed amorphagnosia and mild ahylognosia. Our case is the first to present with only amorphagnosia without tactile agnosia. The mechanism for the well-preserved recognition of real objects may depend on the preserved hylognosia. Of note, there have been no reports showing only ahylognosia without amorphagnosia. Further studies are necessary to clarify whether or not patients with preserved hylognosia or morphagnosia retain the ability to perceive real objects. PMID:28559827

Topographic generalization of tactile perceptual learning.

PubMed

Harrar, Vanessa; Spence, Charles; Makin, Tamar R

2014-02-01

Perceptual learning can improve our sensory abilities. Understanding its underlying mechanisms, in particular, when perceptual learning generalizes, has become a focus of research and controversy. Specifically, there is little consensus regarding the extent to which tactile perceptual learning generalizes across fingers. We measured tactile orientation discrimination abilities on 4 fingers (index and middle fingers of both hands), using psychophysical measures, before and after 4 training sessions on 1 finger. Given the somatotopic organization of the hand representation in the somatosensory cortex, the topography of the cortical areas underlying tactile perceptual learning can be inferred from the pattern of generalization across fingers; only fingers sharing cortical representation with the trained finger ought to improve with it. Following training, performance improved not only for the trained finger but also for its adjacent and homologous fingers. Although these fingers were not exposed to training, they nevertheless demonstrated similar levels of learning as the trained finger. Conversely, the performance of the finger that was neither adjacent nor homologous to the trained finger was unaffected by training, despite the fact that our procedure was designed to enhance generalization, as described in recent visual perceptual learning research. This pattern of improved performance is compatible with previous reports of neuronal receptive fields (RFs) in the primary somatosensory cortex (SI) spanning adjacent and homologous digits. We conclude that perceptual learning rooted in low-level cortex can still generalize, and suggest potential applications for the neurorehabilitation of syndromes associated with maladaptive plasticity in SI. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Effects of morphine on respiratory load detection, load magnitude perception and tactile sensation in obstructive sleep apnea.

PubMed

Tomazini Martins, Rodrigo; Carberry, Jayne C; Gandevia, Simon C; Butler, Jane E; Eckert, Danny J

2018-04-26

Pharyngeal and respiratory sensation is impaired in obstructive sleep apnea (OSA). Opioids may further diminish respiratory sensation. Thus, protective pharyngeal neuromuscular and arousal responses to airway occlusion that rely on respiratory sensation could be impaired with opioids to worsen OSA severity. However, little is known about the effects of opioids on upper airway and respiratory sensation in people with OSA. This study was designed to determine the effects of 40mg of MS-Contin on tactile sensation, respiratory load detection and respiratory magnitude perception in people with OSA during wakefulness. A double-blind, randomized, cross-over design (1 week wash-out) was used. 21 men with untreated OSA (apnea/hypopnea index=26{plus minus}17events/h) recruited from a larger clinical study completed the protocol. Tactile sensation using von Frey filaments on the back of the hand, internal mucosa of the cheek, uvula and posterior pharyngeal wall were not different between placebo and morphine (e.g. posterior wall=0.16[0.16,0.4]vs. 0.4[0.14,1.8]g, p=0.261). Similarly, compared to placebo, morphine did not alter respiratory load detection thresholds (nadir mask pressure detected=-2.05[-3.37,-1.55] vs. -2.19[-3.36,-1.41]cmH 2 O, p=0.767), or respiratory load magnitude perception (mean Borg scores during a 5 resistive load [range: 5-126cmH 2 O/L/s] protocol=4.5{plus minus}1.6 vs. 4.2{plus minus}1.2, p=0.347) but did reduce minute ventilation during quiet breathing (11.4{plus minus}3.3 vs. 10.7{plus minus}2.6L/min, p<0.01). These findings indicate that 40mg of MS-Contin does not systematically impair tactile or respiratory sensation in men with mild to moderate, untreated, OSA. This suggests that altered respiratory sensation to acute mechanical stimuli is not likely to be a mechanism that contributes to worsening of OSA with a moderate dose of morphine.

Tactile Instrument for Aviation

DTIC Science & Technology

2000-07-30

response times using 8 tactor locations was repeated with a dual memory /tracking task or an air combat simulation to evaluate the effectiveness of the...Global Positioning/Inertial Navigation System technologies into a single system for evaluation in an UH-60 Helicopter. A 10-event test operation was... evaluation of the following technology areas need to be pursued: • Integration of tactile instruments with helmet mounted displays and 3D audio displays

Spatiotemporal integration for tactile localization during arm movements: a probabilistic approach.

PubMed

Maij, Femke; Wing, Alan M; Medendorp, W Pieter

2013-12-01

It has been shown that people make systematic errors in the localization of a brief tactile stimulus that is delivered to the index finger while they are making an arm movement. Here we modeled these spatial errors with a probabilistic approach, assuming that they follow from temporal uncertainty about the occurrence of the stimulus. In the model, this temporal uncertainty converts into a spatial likelihood about the external stimulus location, depending on arm velocity. We tested the prediction of the model that the localization errors depend on arm velocity. Participants (n = 8) were instructed to localize a tactile stimulus that was presented to their index finger while they were making either slow- or fast-targeted arm movements. Our results confirm the model's prediction that participants make larger localization errors when making faster arm movements. The model, which was used to fit the errors for both slow and fast arm movements simultaneously, accounted very well for all the characteristics of these data with temporal uncertainty in stimulus processing as the only free parameter. We conclude that spatial errors in dynamic tactile perception stem from the temporal precision with which tactile inputs are processed.

Do patients with chronic unilateral orofacial pain due to a temporomandibular disorder show increased attending to somatosensory input at the painful side of the jaw?

PubMed

Van Damme, Stefaan; Vanden Bulcke, Charlotte; Van Den Berghe, Linda; Poppe, Louise; Crombez, Geert

2018-01-01

Patients with chronic orofacial pain due to temporomandibular disorders (TMD) display alterations in somatosensory processing at the jaw, such as amplified perception of tactile stimuli, but the underlying mechanisms remain unclear. This study investigated one possible explanation, namely hypervigilance, and tested if TMD patients with unilateral pain showed increased attending to somatosensory input at the painful side of the jaw. TMD patients with chronic unilateral orofacial pain ( n  = 20) and matched healthy volunteers ( n  = 20) performed a temporal order judgment (TOJ) task indicated which one of two tactile stimuli, presented on each side of the jaw, they had perceived first. TOJ methodology allows examining spatial bias in somatosensory processing speed. Furthermore, after each block of trials, the participants rated the perceived intensity of tactile stimuli separately for both sides of the jaw. Finally, questionnaires assessing pain catastrophizing, fear-avoidance beliefs, and pain vigilance, were completed. TMD patients tended to perceive tactile stimuli at the painful jaw side as occurring earlier in time than stimuli at the non-painful side but this effect did not reach conventional levels of significance ( p  = .07). In the control group, tactile stimuli were perceived as occurring simultaneously. Secondary analyses indicated that the magnitude of spatial bias in the TMD group is positively associated with the extent of fear-avoidance beliefs. Overall, intensity ratings of tactile stimuli were significantly higher in the TMD group than in the control group, but there was no significant difference between the painful and non-painful jaw side in the TMD patients. The hypothesis that TMD patients with chronic unilateral orofacial pain preferentially attend to somatosensory information at the painful side of the jaw was not statistically supported, although lack of power could not be ruled out as a reason for this. The findings are discussed within

Tactile Sun: Bringing an Invisible Universe to the Visually Impaired

NASA Astrophysics Data System (ADS)

Isidro, G. M.; Pantoja, C. A.

2014-07-01

A tactile model of the Sun has been created as a strategy for communicating astronomy to the blind or visually impaired, and as a useful outreach tool for general audiences. The model design was a collaboration between an education specialist, an astronomy specialist and a sculptor. The tactile Sun has been used at astronomy outreach events in Puerto Rico to make activities more inclusive and to increase public awareness of the needs of those with disabilities.

Development of a biomimetic roughness sensor for tactile information with an elastomer

NASA Astrophysics Data System (ADS)

Choi, Jae-Young; Kim, Sung Joon; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

2016-04-01

Human uses various sensational information for identifying an object. When contacting an unidentified object with no vision, tactile sensation provides a variety of information to perceive. Tactile sensation plays an important role to recognize a shape of surfaces from touching. In robotic fields, tactile sensation is especially meaningful. Robots can perform more accurate job using comprehensive tactile information. And in case of using sensors made by soft material like silicone, sensors can be used in various situations. So we are developing a tactile sensor with soft materials. As the conventional robot operates in a controlled environment, it is a good model to make robots more available at any circumstance that sensory systems of living things. For example, there are lots of mechanoreceptors that each of them has different roles detecting simulation in side of human skin tissue. By mimicking the mechanoreceptor, a sensory system can be realized more closely to human being. It is known that human obtains roughness information through scanning the surface with fingertips. During that times, subcutaneous mechanoreceptors detect vibration. In the same way, while a robot is scanning a surface of object, a roughness sensor developed detects vibrations generated between contacting two surfaces. In this research, a roughness sensor made by an elastomer was developed and experiment for perception of objects was conducted. We describe means to compare the roughness of objects with a newly developed sensor.

A slow-adapting microfluidic-based tactile sensor

NASA Astrophysics Data System (ADS)

Tseng, W.-Y.; Fisher, J. S.; Prieto, J. L.; Rinaldi, K.; Alapati, G.; Lee, A. P.

2009-08-01

We present a microfluidic-based tactile sensor mimicking the human slow-adapting mechanoreceptor such as Merkel's disc. The sensor is composed of a polyimide (PI)/polydimethylsiloxane (PDMS) multilayer structure. The device uses a hemispherical reservoir filled with electrolyte solution in the PDMS layer, a microchannel in the PI layer and a pair of sensing electrodes below the microchannel as the force transducer. The tactile signal is detected as the impedance change resulting predominantly from the resistance variance due to the electrodes coverage by the 1M NaCl solution and is measured across the electrode pair. The sensor response is linear and the working range is shown to be in the range of 0-1.8 N. The characterization results also demonstrate the sensing of various levels of forces and its long-term signal stability.

Neuronal activity in somatosensory cortex related to tactile exploration

PubMed Central

Fortier-Poisson, Pascal

2015-01-01

The very light contact forces (∼0.60 N) applied by the fingertips during tactile exploration reveal a clearly optimized sensorimotor strategy. To investigate the cortical mechanisms involved with this behavior, we recorded 230 neurons in the somatosensory cortex (S1), as two monkeys scanned different surfaces with the fingertips in search of a tactile target without visual feedback. During the exploration, the monkeys, like humans, carefully controlled the finger forces. High-friction surfaces offering greater tangential shear force resistance to the skin were associated with decreased normal contact forces. The activity of one group of neurons was modulated with either the normal or tangential force, with little or no influence from the orthogonal force component. A second group responded to kinetic friction or the ratio of tangential to normal forces rather than responding to a specific parameter, such as force magnitude or direction. A third group of S1 neurons appeared to respond to particular vectors of normal and tangential force on the skin. Although 45 neurons correlated with scanning speed, 32 were also modulated by finger forces, suggesting that forces on the finger should be considered as the primary parameter encoding the skin compliance and that finger speed is a secondary parameter that co-varies with finger forces. Neurons (102) were also tested with different textures, and the activity of 62 of these increased or decreased in relation to the surface friction. PMID:26467519

Allodynia mediated by C-tactile afferents in human hairy skin.

PubMed

Nagi, Saad S; Rubin, Troy K; Chelvanayagam, David K; Macefield, Vaughan G; Mahns, David A

2011-08-15

We recently showed a contribution of low-threshold cutaneous mechanoreceptors to vibration-evoked changes in the perception of muscle pain. Neutral-touch stimulation (vibration) of the hairy skin during underlying muscle pain evoked an overall increase in pain intensity, i.e. allodynia. This effect appeared to be dependent upon cutaneous afferents, as allodynia was abolished by intradermal anaesthesia. However, it remains unclear whether allodynia results from activation of a single class of cutaneous afferents or the convergence of inputs from multiple classes. Intriguingly, no existing human study has examined the contribution of C-tactile (CT) afferents to allodynia. Detailed psychophysical observations were made in 29 healthy subjects (18 males and 11 females). Sustained muscle pain was induced by infusing hypertonic saline (HS: 5%) into tibialis anterior muscle (TA). Sinusoidal vibration (200 Hz–200 μm) was applied to the hairy skin overlying TA. Pain ratings were recorded using a visual analogue scale (VAS). In order to evaluate the role of myelinated and unmyelinated cutaneous afferents in the expression of vibration-evoked allodynia, compression block of the sciatic nerve, and low-dose intradermal anaesthesia (Xylocaine 0.25%) were used, respectively. In addition, the modulation of muscle pain by gentle brushing (1.0 and 3.0 cm s(−1))--known to excite CT fibres--was examined. Brushing stimuli were applied to the hairy skin with all fibres intact and following the blockade of myelinated afferents. During tonic muscle pain (VAS 4–6), vibration evoked a significant and reproducible increase in muscle pain (allodynia) that persisted following compression of myelinated afferents. During compression block, the sense of vibration was abolished, but the vibration-evoked allodynia persisted. In contrast, selective anaesthesia of unmyelinated cutaneous afferents abolished the allodynia, whereas the percept of vibration remained unaffected. Furthermore

Current source density correlates of cerebellar Golgi and Purkinje cell responses to tactile input

PubMed Central

Tahon, Koen; Wijnants, Mike; De Schutter, Erik

2011-01-01

The overall circuitry of the cerebellar cortex has been known for over a century, but the function of many synaptic connections remains poorly characterized in vivo. We used a one-dimensional multielectrode probe to estimate the current source density (CSD) of Crus IIa in response to perioral tactile stimuli in anesthetized rats and to correlate current sinks and sources to changes in the spike rate of corecorded Golgi and Purkinje cells. The punctate stimuli evoked two distinct early waves of excitation (at <10 and ∼20 ms) associated with current sinks in the granular layer. The second wave was putatively of corticopontine origin, and its associated sink was located higher in the granular layer than the first trigeminal sink. The distinctive patterns of granular-layer sinks correlated with the spike responses of corecorded Golgi cells. In general, Golgi cell spike responses could be linearly reconstructed from the CSD profile. A dip in simple-spike activity of coregistered Purkinje cells correlated with a current source deep in the molecular layer, probably generated by basket cell synapses, interspersed between sparse early sinks presumably generated by synapses from granule cells. The late (>30 ms) enhancement of simple-spike activity in Purkinje cells was characterized by the absence of simultaneous sinks in the granular layer and by the suppression of corecorded Golgi cell activity, pointing at inhibition of Golgi cells by Purkinje axon collaterals as a likely mechanism of late Purkinje cell excitation. PMID:21228303

Reduced modulation of thalamocortical connectivity during exposure to sensory stimuli in ASD.

PubMed

Green, Shulamite A; Hernandez, Leanna; Bookheimer, Susan Y; Dapretto, Mirella

2017-05-01

Recent evidence for abnormal thalamic connectivity in autism spectrum disorders (ASD) and sensory processing disorders suggests the thalamus may play a role in sensory over-responsivity (SOR), an extreme negative response to sensory stimuli, which is common in ASD. However, there is yet little understanding of changes in thalamic connectivity during exposure to aversive sensory inputs in individuals with ASD. In particular, the pulvinar nucleus of the thalamus is implicated in atypical sensory processing given its role in selective attention, regulation, and sensory integration. This study aimed to examine the role of pulvinar connectivity in ASD during mildly aversive sensory input. Functional magnetic resonance imaging was used to examine connectivity with the pulvinar during exposure to mildly aversive auditory and tactile stimuli in 38 youth (age 9-17; 19 ASD, 19 IQ-matched typically developing (TD)). Parents rated children's SOR severity on two standard scales. Compared to TD, ASD participants displayed aberrant modulation of connectivity between pulvinar and cortex (including sensory-motor and prefrontal regions) during sensory stimulation. In ASD participants, pulvinar-amygdala connectivity was correlated with severity of SOR symptoms. Deficits in modulation of thalamocortical connectivity in youth with ASD may reflect reduced thalamo-cortical inhibition in response to sensory stimulation, which could lead to difficulty filtering out and/or integrating sensory information. An increase in amygdala connectivity with the pulvinar might be partially responsible for deficits in selective attention as the amygdala signals the brain to attend to distracting sensory stimuli. Autism Res 2017, 10: 801-809. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Stiffness mapping prostate biopsy samples using a tactile sensor.

PubMed

Peng, Qiyu; Omata, Sadao; Peehl, Donna M; Constantinou, Chris E

2011-01-01

Previous studies have demonstrated that the stiffness of cancerous cells reflects their pathological stage and progression rates, with increased cancerous cell stiffness associated with increased aggressiveness. Therefore, the elasticity of the cancerous cells has the potential to be used as an indicator of the cancer's aggressiveness. However, the sensitivity and resolution of current palpation and imaging techniques are not sufficient to detect small cancerous tissues. In previous studies, we developed a tactile-based device to map with high resolution the stiffness of a tissue section. The purpose of this study is to evaluate this device using different tissues (BPH, Cancer and PZ) collected from human prostates. The preliminary results show that the tactile device is sensitive enough to tell the differences of the stiffness of different tissues. The results also disclosed the factors (humidity, temperature and tissue degradation) which could dramatically affect the results of stiffness mapping. The tactile technology described in this paper has the potential to help disclose the underlying mechanical mechanisms that lead to increased stiffness in prostate tumors.

Bioinspired active whisker sensor for robotic vibrissal tactile sensing

NASA Astrophysics Data System (ADS)

Ju, Feng; Ling, Shih-Fu

2014-12-01

A whisker transducer (WT) inspired by rat’s vibrissal tactile perception is proposed based on a transduction matrix model characterizing the electro-mechanical transduction process in both forward and backward directions. It is capable of acting as an actuator to sweep the whisker and simultaneously as a sensor to sense the force, motion, and mechanical impedance at whisker tip. Its validity is confirmed by numerical simulation using a finite element model. A prototype is then fabricated and its transduction matrix is determined by parameter identification. The calibrated WT can accurately sense mechanical impedance which is directly related to stiffness, mass and damping. Subsequent vibrissal tactile sensing of sandpaper texture reveals that the real part of mechanical impedance sensed by WT is correlated with sandpaper roughness. Texture discrimination is successfully achieved by inputting the real part to a k-means clustering algorithm. The mechanical impedance sensing ability as well as other features of the WT such as simultaneous-actuation-and-sensing makes it a good solution to robotic tactile sensing.

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies

PubMed Central

Pestell, Nicholas; Cramphorn, Luke; Winstone, Benjamin; Giannaccini, Maria Elena; Rossiter, Jonathan; Lepora, Nathan F.

2018-01-01

Abstract Tactile sensing is an essential component in human–robot interaction and object manipulation. Soft sensors allow for safe interaction and improved gripping performance. Here we present the TacTip family of sensors: a range of soft optical tactile sensors with various morphologies fabricated through dual-material 3D printing. All of these sensors are inspired by the same biomimetic design principle: transducing deformation of the sensing surface via movement of pins analogous to the function of intermediate ridges within the human fingertip. The performance of the TacTip, TacTip-GR2, TacTip-M2, and TacCylinder sensors is here evaluated and shown to attain submillimeter accuracy on a rolling cylinder task, representing greater than 10-fold super-resolved acuity. A version of the TacTip sensor has also been open-sourced, enabling other laboratories to adopt it as a platform for tactile sensing and manipulation research. These sensors are suitable for real-world applications in tactile perception, exploration, and manipulation, and will enable further research and innovation in the field of soft tactile sensing. PMID:29297773

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies.

PubMed

Ward-Cherrier, Benjamin; Pestell, Nicholas; Cramphorn, Luke; Winstone, Benjamin; Giannaccini, Maria Elena; Rossiter, Jonathan; Lepora, Nathan F

2018-04-01

Tactile sensing is an essential component in human-robot interaction and object manipulation. Soft sensors allow for safe interaction and improved gripping performance. Here we present the TacTip family of sensors: a range of soft optical tactile sensors with various morphologies fabricated through dual-material 3D printing. All of these sensors are inspired by the same biomimetic design principle: transducing deformation of the sensing surface via movement of pins analogous to the function of intermediate ridges within the human fingertip. The performance of the TacTip, TacTip-GR2, TacTip-M2, and TacCylinder sensors is here evaluated and shown to attain submillimeter accuracy on a rolling cylinder task, representing greater than 10-fold super-resolved acuity. A version of the TacTip sensor has also been open-sourced, enabling other laboratories to adopt it as a platform for tactile sensing and manipulation research. These sensors are suitable for real-world applications in tactile perception, exploration, and manipulation, and will enable further research and innovation in the field of soft tactile sensing.

Tactile Data Entry for Extravehicular Activity

NASA Technical Reports Server (NTRS)

Adams, Richard J.; Olowin, Aaron B.; Hannaford, Blake; Sands, O Scott

2012-01-01

In the task-saturated environment of extravehicular activity (EVA), an astronaut's ability to leverage suit-integrated information systems is limited by a lack of options for data entry. In particular, bulky gloves inhibit the ability to interact with standard computing interfaces such as a mouse or keyboard. This paper presents the results of a preliminary investigation into a system that permits the space suit gloves themselves to be used as data entry devices. Hand motion tracking is combined with simple finger gesture recognition to enable use of a virtual keyboard, while tactile feedback provides touch-based context to the graphical user interface (GUI) and positive confirmation of keystroke events. In human subject trials, conducted with twenty participants using a prototype system, participants entered text significantly faster with tactile feedback than without (p = 0.02). The results support incorporation of vibrotactile information in a future system that will enable full touch typing and general mouse interactions using instrumented EVA gloves.

Transcranial Direct Current Stimulation Over the Primary and Secondary Somatosensory Cortices Transiently Improves Tactile Spatial Discrimination in Stroke Patients

PubMed Central

Fujimoto, Shuhei; Kon, Noriko; Otaka, Yohei; Yamaguchi, Tomofumi; Nakayama, Takeo; Kondo, Kunitsugu; Ragert, Patrick; Tanaka, Satoshi

2016-01-01

In healthy subjects, dual hemisphere transcranial direct current stimulation (tDCS) over the primary (S1) and secondary somatosensory cortices (S2) has been found to transiently enhance tactile performance. However, the effect of dual hemisphere tDCS on tactile performance in stroke patients with sensory deficits remains unknown. The purpose of this study was to investigate whether dual hemisphere tDCS over S1 and S2 could enhance tactile discrimination in stroke patients. We employed a double-blind, crossover, sham-controlled experimental design. Eight chronic stroke patients with sensory deficits participated in this study. We used a grating orientation task (GOT) to measure the tactile discriminative threshold of the affected and non-affected index fingers before, during, and 10 min after four tDCS conditions. For both the S1 and S2 conditions, we placed an anodal electrode over the lesioned hemisphere and a cathodal electrode over the opposite hemisphere. We applied tDCS at an intensity of 2 mA for 15 min in both S1 and S2 conditions. We included two sham conditions in which the positions of the electrodes and the current intensity were identical to that in the S1 and S2 conditions except that current was delivered for the initial 15 s only. We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition. GOT thresholds were not significantly different between the S1 and S2 conditions at any time point. We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction. PMID:27064531

Maintenance of tactile short-term memory for locations is mediated by spatial attention.

PubMed

Katus, Tobias; Andersen, Søren K; Müller, Matthias M

2012-01-01

According to the attention-based rehearsal hypothesis, maintenance of spatial information is mediated by covert orienting towards memorized locations. In a somatosensory memory task, participants simultaneously received bilateral pairs of mechanical sample pulses. For each hand, sample stimuli were randomly assigned to one of three locations (fingers). A subsequent visual retro-cue determined whether the left or right hand sample was to be memorized. The retro-cue elicited lateralized activity reflecting the location of the relevant sample stimulus. Sensory processing during the retention period was probed by task-irrelevant pulses randomized to locations at the cued and uncued hand. The somatosensory N140 was enhanced for probes delivered to the cued hand, relative to uncued. Probes presented shortly after the retro-cue showed greatest attentional modulations. This suggests that transient contributions from retrospective selection overlapped with the sustained effect of attention-based rehearsal. In conclusion, focal attention shifts within tactile mnemonic content occurred after retro-cues and guided sensory processing during retention. Copyright © 2011 Elsevier B.V. All rights reserved.

Mechanisms underlying a thalamocortical transformation during active tactile sensation

PubMed Central

Gutnisky, Diego Adrian; Yu, Jianing; Hires, Samuel Andrew; To, Minh-Son; Svoboda, Karel

2017-01-01

During active somatosensation, neural signals expected from movement of the sensors are suppressed in the cortex, whereas information related to touch is enhanced. This tactile suppression underlies low-noise encoding of relevant tactile features and the brain’s ability to make fine tactile discriminations. Layer (L) 4 excitatory neurons in the barrel cortex, the major target of the somatosensory thalamus (VPM), respond to touch, but have low spike rates and low sensitivity to the movement of whiskers. Most neurons in VPM respond to touch and also show an increase in spike rate with whisker movement. Therefore, signals related to self-movement are suppressed in L4. Fast-spiking (FS) interneurons in L4 show similar dynamics to VPM neurons. Stimulation of halorhodopsin in FS interneurons causes a reduction in FS neuron activity and an increase in L4 excitatory neuron activity. This decrease of activity of L4 FS neurons contradicts the "paradoxical effect" predicted in networks stabilized by inhibition and in strongly-coupled networks. To explain these observations, we constructed a model of the L4 circuit, with connectivity constrained by in vitro measurements. The model explores the various synaptic conductance strengths for which L4 FS neurons actively suppress baseline and movement-related activity in layer 4 excitatory neurons. Feedforward inhibition, in concert with recurrent intracortical circuitry, produces tactile suppression. Synaptic delays in feedforward inhibition allow transmission of temporally brief volleys of activity associated with touch. Our model provides a mechanistic explanation of a behavior-related computation implemented by the thalamocortical circuit. PMID:28591219

An Extreme Learning Machine-Based Neuromorphic Tactile Sensing System for Texture Recognition.

PubMed

Rasouli, Mahdi; Chen, Yi; Basu, Arindam; Kukreja, Sunil L; Thakor, Nitish V

2018-04-01

Despite significant advances in computational algorithms and development of tactile sensors, artificial tactile sensing is strikingly less efficient and capable than the human tactile perception. Inspired by efficiency of biological systems, we aim to develop a neuromorphic system for tactile pattern recognition. We particularly target texture recognition as it is one of the most necessary and challenging tasks for artificial sensory systems. Our system consists of a piezoresistive fabric material as the sensor to emulate skin, an interface that produces spike patterns to mimic neural signals from mechanoreceptors, and an extreme learning machine (ELM) chip to analyze spiking activity. Benefiting from intrinsic advantages of biologically inspired event-driven systems and massively parallel and energy-efficient processing capabilities of the ELM chip, the proposed architecture offers a fast and energy-efficient alternative for processing tactile information. Moreover, it provides the opportunity for the development of low-cost tactile modules for large-area applications by integration of sensors and processing circuits. We demonstrate the recognition capability of our system in a texture discrimination task, where it achieves a classification accuracy of 92% for categorization of ten graded textures. Our results confirm that there exists a tradeoff between response time and classification accuracy (and information transfer rate). A faster decision can be achieved at early time steps or by using a shorter time window. This, however, results in deterioration of the classification accuracy and information transfer rate. We further observe that there exists a tradeoff between the classification accuracy and the input spike rate (and thus energy consumption). Our work substantiates the importance of development of efficient sparse codes for encoding sensory data to improve the energy efficiency. These results have a significance for a wide range of wearable, robotic

Tactile interactions activate mirror system regions in the human brain.

PubMed

McKyton, Ayelet

2011-12-07

Communicating with others is essential for the development of a society. Although types of communications, such as language and visual gestures, were thoroughly investigated in the past, little research has been done to investigate interactions through touch. To study this we used functional magnetic resonance imaging. Twelve participants were scanned with their eyes covered while stroking four kinds of items, representing different somatosensory stimuli: a human hand, a realistic rubber hand, an object, and a simple texture. Although the human and the rubber hands had the same overall shape, in three regions there was significantly more blood oxygen level dependent activation when touching the real hand: the anterior medial prefrontal cortex, the ventral premotor cortex, and the posterior superior temporal cortex. The last two regions are part of the mirror network and are known to be activated through visual interactions such as gestures. Interestingly, in this study, these areas were activated through a somatosensory interaction. A control experiment was performed to eliminate confounds of temperature, texture, and imagery, suggesting that the activation in these areas was correlated with the touch of a human hand. These results reveal the neuronal network working behind human tactile interactions, and highlight the participation of the mirror system in such functions.

Functionalization of Tactile Sensation for Robot Based on Haptograph and Modal Decomposition

NASA Astrophysics Data System (ADS)

Yokokura, Yuki; Katsura, Seiichiro; Ohishi, Kiyoshi

In the real world, robots should be able to recognize the environment in order to be of help to humans. A video camera and a laser range finder are devices that can help robots recognize the environment. However, these devices cannot obtain tactile information from environments. Future human-assisting-robots should have the ability to recognize haptic signals, and a disturbance observer can possibly be used to provide the robot with this ability. In this study, a disturbance observer is employed in a mobile robot to functionalize the tactile sensation. This paper proposes a method that involves the use of haptograph and modal decomposition for the haptic recognition of road environments. The haptograph presents a graphic view of the tactile information. It is possible to classify road conditions intuitively. The robot controller is designed by considering the decoupled modal coordinate system, which consists of translational and rotational modes. Modal decomposition is performed by using a quarry matrix. Once the robot is provided with the ability to recognize tactile sensations, its usefulness to humans will increase.

Task Analysis Schema Based on Cognitive Style and Supplantational Instructional Design with Application to an Air Force Training Course.

DTIC Science & Technology

1980-02-01

ADOAA82 342 OKLAHOMA UNIV NORMAN COLL OF EDUCATION F/B 5/9 TASK ANALYSIS SCHEMA BASED ON COGNITIVE STYLE AND SUPPLANFATION--ETC(U) FEB GO F B AUSBURN...separately- perceived fragments) 6. Tasks requiring use of a. Visual/haptic (pre- kinesthetic or tactile ference for kinesthetic stimuli stimuli; ability...to transform kinesthetic stimuli into visual images; ability to learn directly from tactile or kinesthet - ic impressions) b. Field independence/de

Symbol recognition produced by points of tactile stimulation: the illusion of linear continuity.

PubMed

Gonzales, G R

1996-11-01

To determine whether tactile receptive communication is possible through the use of a mechanical device that produces the phi phenomenon on the body surface. Twenty-six subjects (11 blind and 15 sighted participants) were tested with use of a tactile communication device (TCD) that produces an illusion of linear continuity forming numbers on the dorsal aspect of the wrist. Recognition of a number or number set was the goal. A TCD with protruding and vibrating solenoids produced sequentially delivered points of cutaneous stimulation along a pattern resembling numbers and created the illusion of dragging a vibrating stylet to form numbers, similar to what might be felt by testing for graphesthesia. Blind subjects recognized numbers with fewer trials than did sighted subjects, although all subjects were able to recognize all the numbers produced by the TCD. Subjects who had been blind since birth and had no prior tactile exposure to numbers were able to draw the numbers after experiencing them delivered by the TCD even though they did not recognize their meaning. The phi phenomenon is probably responsible for the illusion of continuous lines in the shape of numbers as produced by the TCD. This tactile illusion could potentially be used for more complex tactile communications such as letters and words.

The effect of vertical and horizontal symmetry on memory for tactile patterns in late blind individuals.

PubMed

Cattaneo, Zaira; Vecchi, Tomaso; Fantino, Micaela; Herbert, Andrew M; Merabet, Lotfi B

2013-02-01

Visual stimuli that exhibit vertical symmetry are easier to remember than stimuli symmetric along other axes, an advantage that extends to the haptic modality as well. Critically, the vertical symmetry memory advantage has not been found in early blind individuals, despite their overall superior memory, as compared with sighted individuals, and the presence of an overall advantage for identifying symmetric over asymmetric patterns. The absence of the vertical axis memory advantage in the early blind may depend on their total lack of visual experience or on the effect of prolonged visual deprivation. To disentangle this issue, in this study, we measured the ability of late blind individuals to remember tactile spatial patterns that were either vertically or horizontally symmetric or asymmetric. Late blind participants showed better memory performance for symmetric patterns. An additional advantage for the vertical axis of symmetry over the horizontal one was reported, but only for patterns presented in the frontal plane. In the horizontal plane, no difference was observed between vertical and horizontal symmetric patterns, due to the latter being recalled particularly well. These results are discussed in terms of the influence of the spatial reference frame adopted during exploration. Overall, our data suggest that prior visual experience is sufficient to drive the vertical symmetry memory advantage, at least when an external reference frame based on geocentric cues (i.e., gravity) is adopted.

Using time to investigate space: a review of tactile temporal order judgments as a window onto spatial processing in touch

PubMed Central

Heed, Tobias; Azañón, Elena

2014-01-01

To respond to a touch, it is often necessary to localize it in space, and not just on the skin. The computation of this external spatial location involves the integration of somatosensation with visual and proprioceptive information about current body posture. In the past years, the study of touch localization has received substantial attention and has become a central topic in the research field of multisensory integration. In this review, we will explore important findings from this research, zooming in on one specific experimental paradigm, the temporal order judgment (TOJ) task, which has proven particularly fruitful for the investigation of tactile spatial processing. In a typical TOJ task participants perform non-speeded judgments about the order of two tactile stimuli presented in rapid succession to different skin sites. This task could be solved without relying on external spatial coordinates. However, postural manipulations affect TOJ performance, indicating that external coordinates are in fact computed automatically. We show that this makes the TOJ task a reliable indicator of spatial remapping, and provide an overview over the versatile analysis options for TOJ. We introduce current theories of TOJ and touch localization, and then relate TOJ to behavioral and electrophysiological evidence from other paradigms, probing the benefit of TOJ for the study of spatial processing as well as related topics such as multisensory plasticity, body processing, and pain. PMID:24596561

Tactile suppression of displacement.

PubMed

Ziat, Mounia; Hayward, Vincent; Chapman, C Elaine; Ernst, Marc O; Lenay, Charles

2010-10-01

In vision, the discovery of the phenomenon of saccadic suppression of displacement has made important contributions to the understanding of the stable world problem. Here, we report a similar phenomenon in the tactile modality. When scanning a single Braille dot with two fingers of the same hand, participants were asked to decide whether the dot was stationary or whether it was displaced from one location to another. The stimulus was produced by refreshable Braille devices that have dots that can be swiftly raised and recessed. In some conditions, the dot was stationary. In others, a displacement was created by monitoring the participant's finger position and by switching the dot activation when it was not touched by either finger. The dot displacement was of either 2.5 mm or 5 mm. We found that in certain cases, displaced dots were felt to be stationary. If the displacement was orthogonal to the finger movements, tactile suppression occurred effectively when it was of 2.5 mm, but when the displacement was of 5 mm, the participants easily detected it. If the displacement was medial-lateral, the suppression effect occurred as well, but less often when the apparent movement of the dot opposed the movement of the finger. In such cases, the stimulus appeared sooner than when the brain could predict it from finger movement, supporting a predictive rather than a postdictive differential processing hypothesis.

[Advances in the research of function of Merkel cells in tactile formation of skin].

PubMed

You, X; Wei, Z R

2018-01-20

Skin is the largest sense organ of human, with many mechanoreceptor cells under epidermis or dermis of skin and Merkel cell is one of them. It has been confirmed that Merkel cells play an important role in the process of mechanical transmission of mammalian soft tactile stimulation. Researches showed that Merkel cells had close relation to tactile formation and functioned by Merkel cell-neurite complexes and ion channels Piezo2. This article reviews Merkel cells and the function, problem and prospect of Merkel cells in tactile formation.

Tactile Displays for Orientation, Navigation and Communication in Air, Sea and Land Environments (Les systemes d’affichage tactiles pour l’orientation, la navigation et la communication dans les environments aerien, maritime et terrestre)

DTIC Science & Technology

2008-08-01

objects and “ feel ” the forces applied on the object by the other individual or object. Feedback including active touch or proprioceptive signals (e.g...observer will notice that certain touches will feel “bright” or “cold.” In fact, the “experimenter/observer” has just activated his/her tactile cold...2008). More than a feeling : bringing touch into astronauts’ spatial orientation. Microgravity Science and Technology. (In press). [11] Vos, W.K

Integration of Hand and Finger Location in External Spatial Coordinates for Tactile Localization

ERIC Educational Resources Information Center

Heed, Tobias; Backhaus, Jenny; Roder, Brigitte

2012-01-01

Tactile stimulus location is automatically transformed from somatotopic into external spatial coordinates, rendering information about the location of touch in three-dimensional space. This process is referred to as tactile remapping. Whereas remapping seems to occur automatically for the hands and feet, the fingers may constitute an exception in…

Genetically identified spinal interneurons integrating tactile afferents for motor control

PubMed Central

Panek, Izabela; Farah, Carl

2015-01-01

Our movements are shaped by our perception of the world as communicated by our senses. Perception of sensory information has been largely attributed to cortical activity. However, a prior level of sensory processing occurs in the spinal cord. Indeed, sensory inputs directly project to many spinal circuits, some of which communicate with motor circuits within the spinal cord. Therefore, the processing of sensory information for the purpose of ensuring proper movements is distributed between spinal and supraspinal circuits. The mechanisms underlying the integration of sensory information for motor control at the level of the spinal cord have yet to be fully described. Recent research has led to the characterization of spinal neuron populations that share common molecular identities. Identification of molecular markers that define specific populations of spinal neurons is a prerequisite to the application of genetic techniques devised to both delineate the function of these spinal neurons and their connectivity. This strategy has been used in the study of spinal neurons that receive tactile inputs from sensory neurons innervating the skin. As a result, the circuits that include these spinal neurons have been revealed to play important roles in specific aspects of motor function. We describe these genetically identified spinal neurons that integrate tactile information and the contribution of these studies to our understanding of how tactile information shapes motor output. Furthermore, we describe future opportunities that these circuits present for shedding light on the neural mechanisms of tactile processing. PMID:26445867

Visual and tactile interfaces for bi-directional human robot communication

NASA Astrophysics Data System (ADS)

Barber, Daniel; Lackey, Stephanie; Reinerman-Jones, Lauren; Hudson, Irwin

2013-05-01

Seamless integration of unmanned and systems and Soldiers in the operational environment requires robust communication capabilities. Multi-Modal Communication (MMC) facilitates achieving this goal due to redundancy and levels of communication superior to single mode interaction using auditory, visual, and tactile modalities. Visual signaling using arm and hand gestures is a natural method of communication between people. Visual signals standardized within the U.S. Army Field Manual and in use by Soldiers provide a foundation for developing gestures for human to robot communication. Emerging technologies using Inertial Measurement Units (IMU) enable classification of arm and hand gestures for communication with a robot without the requirement of line-of-sight needed by computer vision techniques. These devices improve the robustness of interpreting gestures in noisy environments and are capable of classifying signals relevant to operational tasks. Closing the communication loop between Soldiers and robots necessitates them having the ability to return equivalent messages. Existing visual signals from robots to humans typically require highly anthropomorphic features not present on military vehicles. Tactile displays tap into an unused modality for robot to human communication. Typically used for hands-free navigation and cueing, existing tactile display technologies are used to deliver equivalent visual signals from the U.S. Army Field Manual. This paper describes ongoing research to collaboratively develop tactile communication methods with Soldiers, measure classification accuracy of visual signal interfaces, and provides an integration example including two robotic platforms.

Weber's Illusion and Body Shape: Anisotropy of Tactile Size Perception on the Hand

ERIC Educational Resources Information Center

Longo, Matthew R.; Haggard, Patrick

2011-01-01

The perceived distance between touches on a single skin surface is larger on regions of high tactile sensitivity than those with lower acuity, an effect known as "Weber's illusion". This illusion suggests that tactile size perception involves a representation of the perceived size of body parts preserving characteristics of the somatosensory…

Brain activations evoked by tactile stimulation varies with the intensity and not with number of receptive fields stimulated: An fMRI study

NASA Astrophysics Data System (ADS)

Ramirez Garzón, Y. T.; Pasaye, E. H.; Barrios, F. A.

2014-11-01

Using functional Magnetic Resonance Imaging (fMRI) it is possible to study the functional anatomy of primary cortices. Cortical representations in the primary somatosensory cortex have shown discrepancies between activations related to the same body region in some studies; these differences have been more pronounced for lower limb representations. The aim of this study was to observe the influence of the tactile stimulus intensity in somatosensory cortical responses using fMRI. Based in the sensitivity and pain threshold of each subject, we used Von Frey filaments for stimulate 12 control subject in three receptive fields on the right thigh. One filament near to sensitivity threshold (VFS), other close to pain threshold (VFP) and one intermediate filament between the two previous thresholds (VFI). The tactile stimulation with VFS produced no activation on SI, while that the contralateral SI was activated by stimulation with VFI in 5 subjects and with the stimulation of VFP in all subjects. Second level statistical analysis showed significant differences between SI activations related to the stimulation with VFP and VFI (VFP > VFI), in the comparison between the applied different intensities, a small cluster of activation was observed on SI for the unique possible contrast (VFP > VFI). The time course per trial for each subject was extracted and averaged to extract the activation in the contralateral SI and compared across the stimulus modalities, between the sites of field receptive stimulated and the intensities used. The time course of tactile stimulus responses revealed a consistent single peak of activity per cycle (30 s), approximately 12 s after the onset of the stimulus, with exception of the VFI stimulation,_which showed the peak at 10 s. Thus, our results indicate that the cortical representation of a tactile stimulus with fMRI is modulated for the intensity of the stimulus applied.

[Passive tactile stimulation and its clinical and neurophysiological repercussions (P300) in blind children with symptoms of attention deficit disorder].

PubMed

Serrano-Marugán, Isabel; Herrera, Begoña; Romero, Sara; Nogales, Ramón; Poch-Broto, Joaquín; Quintero, Javier; Ortiz, Tomás

2014-02-24

Tactile stimulation is key for the posterior brain re-organization activity and attention processes, however the impact of tactile stimulation on attention deficit disorder (ADD) in blind children remains unexplored. We carried out a study with children having or not ADD (four per group). The subjects have been exposed during six months to tactile stimulation protocol consisting in two daily sessions (morning and afternoon sessions) of 30 minutes each. We have measured the ability to detect an infrequent tactile stimulus, reaction time, latency of P300, sources of brain activity, and ADD clinical symptoms, before and after tactile training. Passive tactile stimulation significantly improves ADD clinical symptoms, particularly attention, behavior and self-control of involuntary movements and tics. In addition, tactile stimulation changes the pattern of brain activity in ADD blind children inducing activity in frontal and occipital areas, which could be associated to a compensation of the attention deficit. Passive tactile stimulation training may improve ADD clinical symptoms and can reorganize the pattern of brain activity in blind ADD children.

The Invisible Universe: A Tactile and Braille Exhibit of Astronomical Images

NASA Astrophysics Data System (ADS)

Arcand, Kimberly; Lestition, K.; Watzke, M.; Steel, S.

2010-01-01

As part of the "From Earth to the Universe" (FETTU) project, a NASA-funded tactile exhibit for the visually impaired community was launched in July 2009 at the Martin Luther King Library in D.C. The exhibit is part of the global FETTU exhibit, a project of the International Year of Astronomy 2009. The science content of the exhibit includes explanations of our Sun, Eta Carinae, Crab Nebula, Whirlpool Galaxy, and the electromagnetic spectrum, and was adapted from the NASA-funded Braille/tactile book Touch the Invisible Sky. Multiple geographic locations and venue types have been targeted for the displays. The FETTU-tactile exhibit opens a wider door to experiencing and understanding astronomy, bridging a gap in learning. This exhibit is based upon work supported by the National Aeronautics and Space Administration under proposal 08-EPO08-0068 issued through the Science Mission Directorate.

Active tactile sampling by an insect in a step-climbing paradigm

PubMed Central

Krause, André F.; Dürr, Volker

2012-01-01

Many insects actively explore their near-range environment with their antennae. Stick insects (Carausius morosus) rhythmically move their antennae during walking and respond to antennal touch by repetitive tactile sampling of the object. Despite its relevance for spatial orientation, neither the spatial sampling patterns nor the kinematics of antennation behavior in insects are understood. Here we investigate unrestrained bilateral sampling movements during climbing of steps. The main objectives are: (1) How does the antennal contact pattern relate to particular object features? (2) How are the antennal joints coordinated during bilateral tactile sampling? We conducted motion capture experiments on freely climbing insects, using steps of different height. Tactile sampling was analyzed at the level of antennal joint angles. Moreover, we analyzed contact patterns on the surfaces of both the obstacle and the antenna itself. Before the first contact, both antennae move in a broad, mostly elliptical exploratory pattern. After touching the obstacle, the pattern switches to a narrower and faster movement, caused by higher cycle frequencies and lower cycle amplitudes in all joints. Contact events were divided into wall- and edge-contacts. Wall contacts occurred mostly with the distal third of the flagellum, which is flexible, whereas edge contacts often occurred proximally, where the flagellum is stiff. The movement of both antennae was found to be coordinated, exhibiting bilateral coupling of functionally analogous joints [e.g., left head-scape (HS) joint with right scape-pedicel (SP) joint] throughout tactile sampling. In comparison, bilateral coupling between homologous joints (e.g., both HS joints) was significantly weaker. Moreover, inter-joint coupling was significantly weaker during the contact episode than before. In summary, stick insects show contact-induced changes in frequency, amplitude and inter-joint coordination during tactile sampling of climbed obstacles

Cross-modal tactile-taste interactions in food evaluations

PubMed Central

Slocombe, B. G.; Carmichael, D.A.; Simner, J.

2016-01-01

Detecting the taste components within a flavoured substance relies on exposing chemoreceptors within the mouth to the chemical components of ingested food. In our paper, we show that the evaluation of taste components can also be influenced by the tactile quality of the food. We first discuss how multisensory factors might influence taste, flavour and smell for both typical and atypical (synaesthetic) populations and we then present two empirical studies showing tactile-taste interactions in the general population. We asked a group of average adults to evaluate the taste components of flavoured food substances, whilst we presented simultaneous cross-sensory visuo-tactile cues within the eating environment. Specifically, we presented foodstuffs between subjects that were otherwise identical but had a rough versus smooth surface, or were served on a rough versus smooth serving-plate. We found no effect of the serving-plate, but we found the rough/smoothness of the foodstuff itself significantly influenced perception: food was rated as significantly more sour if it had a rough (vs. smooth) surface. In modifying taste perception via ostensibly unrelated dimensions, we demonstrate that the detection of tastes within flavours may be influenced by higher level cross-sensory cues. Finally, we suggest that the direction of our cross-sensory associations may speak to the types of hedonic mapping found both in normal multisensory integration, and in the unusual condition of synaesthesia. PMID:26169315

A new tactile gnosis instrument in sensibility testing.

PubMed

Rosén, B; Lundborg, G

1998-01-01

A new quantitative test instrument for the assessment of tactile gnosis--the ability to identify shapes and textures without vision--is introduced. Introductory investigations of validity and reliability are presented. Fifty-four patients (60 hands) with carpal tunnel syndrome, vibration-induced neuropathy, or nerve repair at distal forearm level, and a matched asymptomatic control group were initially examined. After establishing the cut-off limit for normal tactile gnosis, sensitivity and specificity were calculated to determine the discriminative power of the new instrument. A high sensitivity (1.0) of the new shape/texture identification test was found in the group of patients with nerve repair. Given a cut-off limit, the sensitivity was lower in the groups with vibration-induced neuropathy and carpal tunnel syndrome (0.65 and 0.40, respectively), and the specificity of the test was 0.90 to 0.95. In a second step, a group of 52 patients who had had nerve repair at the distal forearm level were examined. Test-retest reliability was good, with a weighted kappa value of 0.79 to 0.81. Good reliability was also shown in the internal consistency of test items, with a Cronbach alpha value of 0.78. These introductory results indicate that the new shape/texture identification test can be useful in the assessment of tactile gnosis.

Tactile spatial resolution in blind braille readers.

PubMed

Van Boven, R W; Hamilton, R H; Kauffman, T; Keenan, J P; Pascual-Leone, A

2000-06-27

To determine if blind people have heightened tactile spatial acuity. Recently, studies using magnetic source imaging and somatosensory evoked potentials have shown that the cortical representation of the reading fingers of blind Braille readers is expanded compared to that of fingers of sighted subjects. Furthermore, the visual cortex is activated during certain tactile tasks in blind subjects but not sighted subjects. The authors hypothesized that the expanded cortical representation of fingers used in Braille reading may reflect an enhanced fidelity in the neural transmission of spatial details of a stimulus. If so, the quantitative limit of spatial acuity would be superior in blind people. The authors employed a grating orientation discrimination task in which threshold performance is accounted for by the spatial resolution limits of the neural image evoked by a stimulus. The authors quantified the psychophysical limits of spatial acuity at the middle and index fingers of 15 blind Braille readers and 15 sighted control subjects. The mean grating orientation threshold was significantly (p = 0.03) lower in the blind group (1.04 mm) compared to the sighted group (1.46 mm). The self-reported dominant reading finger in blind subjects had a mean grating orientation threshold of 0.80 mm, which was significantly better than other fingers tested. Thresholds at non-Braille reading fingers in blind subjects averaged 1.12 mm, which were also superior to sighted subjects' performances. Superior tactile spatial acuity in blind Braille readers may represent an adaptive, behavioral correlate of cortical plasticity.

The Tactile Ethics of Soft Robotics: Designing Wisely for Human-Robot Interaction.

PubMed

Arnold, Thomas; Scheutz, Matthias

2017-06-01

Soft robots promise an exciting design trajectory in the field of robotics and human-robot interaction (HRI), promising more adaptive, resilient movement within environments as well as a safer, more sensitive interface for the objects or agents the robot encounters. In particular, tactile HRI is a critical dimension for designers to consider, especially given the onrush of assistive and companion robots into our society. In this article, we propose to surface an important set of ethical challenges for the field of soft robotics to meet. Tactile HRI strongly suggests that soft-bodied robots balance tactile engagement against emotional manipulation, model intimacy on the bonding with a tool not with a person, and deflect users from personally and socially destructive behavior the soft bodies and surfaces could normally entice.

Anticipation increases tactile stimulus processing in the ipsilateral primary somatosensory cortex.

PubMed

van Ede, Freek; de Lange, Floris P; Maris, Eric

2014-10-01

Stimulus anticipation improves perception. To account for this improvement, we investigated how stimulus processing is altered by anticipation. In contrast to a large body of previous work, we employed a demanding perceptual task and investigated sensory responses that occur beyond early evoked activity in contralateral primary sensory areas: Stimulus-induced modulations of neural oscillations. For this, we recorded magnetoencephalography in 19 humans while they performed a cued tactile identification task involving the identification of either a proximal or a distal stimulation on the fingertips. We varied the cue-target interval between 0 and 1000 ms such that tactile targets occurred at various degrees of anticipation. This allowed us to investigate the influence of anticipation on stimulus processing in a parametric fashion. We observed that anticipation increases the stimulus-induced response (suppression of beta-band oscillations) originating from the ipsilateral primary somatosensory cortex. This occurs in the period in which the tactile memory trace is analyzed and is correlated with the anticipation-induced improvement in tactile perception. We propose that this ipsilateral response indicates distributed processing across bilateral primary sensory cortices, of which the extent increases with anticipation. This constitutes a new and potentially important mechanism contributing to perception and its improvement following anticipation. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Compact Tactile Sensors for Robot Fingers

NASA Technical Reports Server (NTRS)

Martin, Toby B.; Lussy, David; Gaudiano, Frank; Hulse, Aaron; Diftler, Myron A.; Rodriguez, Dagoberto; Bielski, Paul; Butzer, Melisa

2004-01-01

Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure- or force-distribution feedback provided by these sensors is essential for the further development and implementation of robot-control capabilities for humanlike grasping and manipulation.

The Relationship between Gentle Tactile Stimulation on the Fetus and Its Temperament 3 Months after Birth

PubMed Central

Wang, Zhe-Wei; Hua, Jing; Xu, Yu-Hong

2015-01-01

Objective. The aim of this study was to evaluate the effect of gentle tactile stimulation on the fetus in its temperament 3 months after birth. Method. A total of 302 mother-3-month-infant dyads enrolled the retrospective cohort study. 76 mothers had regular gentle tactile stimulation on the fetus in their pregnancy; 62 mothers had irregular tactile stimulation on the fetus, and the rest of 164 mothers who had no tactile stimulation served as nonexposure group. Temperament was assessed using the EITS (a nine-dimensional scale of temperament). Results. Significant difference in temperament type was found among infants in 3 groups at 3 months of age. In the regular practice group, the babies with easy type temperament accounted for 73.7%, which was higher than that in irregular practice group (53.2%, P = 0.012) and that in the control group (42.1%, P < 0.001). Compared to infants in no practice group, the infants who had received regular gentle tactile stimulation before birth were lower in negative mood (P = 0.047) while higher in adaptability (P < 0.001), approach (P = 0.001), and persistence (P = 0.001), respectively. Conclusion. Regular gentle tactile stimulation on fetus may promote the formation of easy type infant temperament. PMID:26180374

High-Accuracy Readout Electronics for Piezoresistive Tactile Sensors

PubMed Central

Vidal-Verdú, Fernando

2017-01-01

The typical layout in a piezoresistive tactile sensor arranges individual sensors to form an array with M rows and N columns. While this layout reduces the wiring involved, it does not allow the values of the sensor resistors to be measured individually due to the appearance of crosstalk caused by the nonidealities of the array reading circuits. In this paper, two reading methods that minimize errors resulting from this phenomenon are assessed by designing an electronic system for array reading, and the results are compared to those obtained using the traditional method, obviating the nonidealities of the reading circuit. The different models were compared by testing the system with an array of discrete resistors. The system was later connected to a tactile sensor with 8 × 7 taxels. PMID:29104229

3D capacitive tactile sensor using DRIE micromachining

NASA Astrophysics Data System (ADS)

Chuang, Chiehtang; Chen, Rongshun

2005-07-01

This paper presents a three dimensional micro capacitive tactile sensor that can detect normal and shear forces which is fabricated using deep reactive ion etching (DRIE) bulk silicon micromachining. The tactile sensor consists of a force transmission plate, a symmetric suspension system, and comb electrodes. The sensing character is based on the changes of capacitance between coplanar sense electrodes. High sensitivity is achieved by using the high aspect ratio interdigital electrodes with narrow comb gaps and large overlap areas. The symmetric suspension mechanism of this sensor can easily solve the coupling problem of measurement and increase the stability of the structure. In this paper, the sensor structure is designed, the capacitance variation of the proposed device is theoretically analyzed, and the finite element analysis of mechanical behavior of the structures is performed.

Short-term memory for spatial configurations in the tactile modality: a comparison with vision.

PubMed

Picard, Delphine; Monnier, Catherine

2009-11-01

This study investigates the role of acquisition constraints on the short-term retention of spatial configurations in the tactile modality in comparison with vision. It tests whether the sequential processing of information inherent to the tactile modality could account for limitation in short-term memory span for tactual-spatial information. In addition, this study investigates developmental aspects of short-term memory for tactual- and visual-spatial configurations. A total of 144 child and adult participants were assessed for their memory span in three different conditions: tactual, visual, and visual with a limited field of view. The results showed lower tactual-spatial memory span than visual-spatial, regardless of age. However, differences in memory span observed between the tactile and visual modalities vanished when the visual processing of information occurred within a limited field. These results provide evidence for an impact of acquisition constraints on the retention of spatial information in the tactile modality in both childhood and adulthood.

Stereo camera based virtual cane system with identifiable distance tactile feedback for the blind.

PubMed

Kim, Donghun; Kim, Kwangtaek; Lee, Sangyoun

2014-06-13

In this paper, we propose a new haptic-assisted virtual cane system operated by a simple finger pointing gesture. The system is developed by two stages: development of visual information delivery assistant (VIDA) with a stereo camera and adding a tactile feedback interface with dual actuators for guidance and distance feedbacks. In the first stage, user's pointing finger is automatically detected using color and disparity data from stereo images and then a 3D pointing direction of the finger is estimated with its geometric and textural features. Finally, any object within the estimated pointing trajectory in 3D space is detected and the distance is then estimated in real time. For the second stage, identifiable tactile signals are designed through a series of identification experiments, and an identifiable tactile feedback interface is developed and integrated into the VIDA system. Our approach differs in that navigation guidance is provided by a simple finger pointing gesture and tactile distance feedbacks are perfectly identifiable to the blind.

Stereo Camera Based Virtual Cane System with Identifiable Distance Tactile Feedback for the Blind

PubMed Central

Kim, Donghun; Kim, Kwangtaek; Lee, Sangyoun

2014-01-01

In this paper, we propose a new haptic-assisted virtual cane system operated by a simple finger pointing gesture. The system is developed by two stages: development of visual information delivery assistant (VIDA) with a stereo camera and adding a tactile feedback interface with dual actuators for guidance and distance feedbacks. In the first stage, user's pointing finger is automatically detected using color and disparity data from stereo images and then a 3D pointing direction of the finger is estimated with its geometric and textural features. Finally, any object within the estimated pointing trajectory in 3D space is detected and the distance is then estimated in real time. For the second stage, identifiable tactile signals are designed through a series of identification experiments, and an identifiable tactile feedback interface is developed and integrated into the VIDA system. Our approach differs in that navigation guidance is provided by a simple finger pointing gesture and tactile distance feedbacks are perfectly identifiable to the blind. PMID:24932864

Visuotactile motion congruence enhances gamma-band activity in visual and somatosensory cortices.

PubMed

Krebber, Martin; Harwood, James; Spitzer, Bernhard; Keil, Julian; Senkowski, Daniel

2015-08-15

When touching and viewing a moving surface our visual and somatosensory systems receive congruent spatiotemporal input. Behavioral studies have shown that motion congruence facilitates interplay between visual and tactile stimuli, but the neural mechanisms underlying this interplay are not well understood. Neural oscillations play a role in motion processing and multisensory integration. They may also be crucial for visuotactile motion processing. In this electroencephalography study, we applied linear beamforming to examine the impact of visuotactile motion congruence on beta and gamma band activity (GBA) in visual and somatosensory cortices. Visual and tactile inputs comprised of gratings that moved either in the same or different directions. Participants performed a target detection task that was unrelated to motion congruence. While there were no effects in the beta band (13-21Hz), the power of GBA (50-80Hz) in visual and somatosensory cortices was larger for congruent compared with incongruent motion stimuli. This suggests enhanced bottom-up multisensory processing when visual and tactile gratings moved in the same direction. Supporting its behavioral relevance, GBA was correlated with shorter reaction times in the target detection task. We conclude that motion congruence plays an important role for the integrative processing of visuotactile stimuli in sensory cortices, as reflected by oscillatory responses in the gamma band. Copyright © 2015 Elsevier Inc. All rights reserved.

Tactile perception of skin and skin cream by friction induced vibrations.

PubMed

Ding, Shuyang; Bhushan, Bharat

2016-11-01

Skin cream smooths, softens, and moistens skin by altering surface roughness and tribological properties of skin. Sliding generates vibrations that activate mechanoreceptors located in skin. The brain interprets tactile information to identify skin feel. Understanding the tactile sensing mechanisms of skin with and without cream treatment is important to numerous applications including cosmetics, textiles, and robotics sensors. In this study, frequency spectra of friction force and friction induced vibration signals were carried out to investigate tactile perception by an artificial finger sliding on skin. The influence of normal load, velocity, and cream treatment time were studied. Coherence between friction force and vibration signals were found. The amplitude of vibration decreased after cream treatment, leading to smoother perception. Increasing normal load or velocity between contacting surfaces generated a smoother perception with cream treatment, but rougher perception without treatment. As cream treatment time increases, skin becomes smoother. The related mechanisms are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Sensing Senses: Tactile Feedback for the Prevention of Decubitus Ulcers

PubMed Central

Verbunt, Marcel

2009-01-01

Decubitus ulcers, also known as pressure sores, is a major problem in health care, in particular for patients with spinal cord injuries. These patients cannot feel the discomfort that would urge healthy people to change their posture. We describe a system that uses a sensor mat to detect problematic postures and provides tactile feedback to the user. The results of our preliminary study with healthy subjects show that the tactile feedback is a viable option to spoken feedback. We envision the system being used for rehabilitation games, but also for everyday Decubitus ulcers prevention. PMID:19949852

The effects of negative emotions on sensory perception: fear but not anger decreases tactile sensitivity

PubMed Central

Kelley, Nicholas J.; Schmeichel, Brandon J.

2014-01-01

Emotions and sensory perceptions are closely intertwined. Of the five senses, sight has been by far the most extensively studied sense in emotion research. Relatively less is known about how emotions influence the other four senses. Touch is essential for nonverbal communication in both humans and other animals. The current investigation tested competing hypotheses about the effect of fear on tactile perception. One hypothesis based on evolutionary considerations predicts that fear enhances sensory perception, including tactile sensitivity. A competing hypothesis based on research on peripheral psychophysiology predicts that fear should decrease tactile sensitivity. Two experiments that induced negative emotional states and measured two-point discrimination ability at the fingertip found that fear reduces tactile sensitivity relative to anger or a neutral control condition (Studies 1 and 2). These findings did not appear to be driven by participants’ naïve beliefs about the influence of emotions on touch (Study 3). The results represent the first evidence of the causal impact of emotional states on tactile sensitivity, are consistent with prior evidence for the peripheral physiological effects of fear, and offer novel empirical grounds for developing and advancing theories of emotional influences on sensory perception. PMID:25202299

The effects of negative emotions on sensory perception: fear but not anger decreases tactile sensitivity.

PubMed

Kelley, Nicholas J; Schmeichel, Brandon J

2014-01-01

Emotions and sensory perceptions are closely intertwined. Of the five senses, sight has been by far the most extensively studied sense in emotion research. Relatively less is known about how emotions influence the other four senses. Touch is essential for nonverbal communication in both humans and other animals. The current investigation tested competing hypotheses about the effect of fear on tactile perception. One hypothesis based on evolutionary considerations predicts that fear enhances sensory perception, including tactile sensitivity. A competing hypothesis based on research on peripheral psychophysiology predicts that fear should decrease tactile sensitivity. Two experiments that induced negative emotional states and measured two-point discrimination ability at the fingertip found that fear reduces tactile sensitivity relative to anger or a neutral control condition (Studies 1 and 2). These findings did not appear to be driven by participants' naïve beliefs about the influence of emotions on touch (Study 3). The results represent the first evidence of the causal impact of emotional states on tactile sensitivity, are consistent with prior evidence for the peripheral physiological effects of fear, and offer novel empirical grounds for developing and advancing theories of emotional influences on sensory perception.

Tactile Object Familiarity in the Blind Brain Reveals the Supramodal Perceptual-Mnemonic Nature of the Perirhinal Cortex

PubMed Central

Cacciamani, Laura; Likova, Lora T.

2016-01-01

This study is the first to investigate the neural underpinnings of tactile object familiarity in the blind during both perception and memory. In the sighted, the perirhinal cortex (PRC) has been implicated in the assessment of visual object familiarity—a crucial everyday task—as evidenced by reduced activation when an object becomes familiar. Here, to examine the PRC’s role in tactile object familiarity in the absence of vision, we trained blind participants on a unique memory-guided drawing technique and measured brain activity while they perceptually explored raised-line drawings, drew them from tactile memory, and scribbled (control). Functional magnetic resonance imaging (fMRI) before and after a week of training revealed a significant decrease in PRC activation from pre- to post-training (i.e., from unfamiliar to familiar) during perceptual exploration as well as memory-guided drawing, but not scribbling. This familiarity-based reduction is the first evidence that the PRC represents tactile object familiarity in the blind. Furthermore, the finding of this effect during both tactile perception and tactile memory provides the critical link in establishing the PRC as a structure whose representations are supramodal for both perception and memory. PMID:27148002

Predicting successful tactile mapping of virtual objects.

PubMed

Brayda, Luca; Campus, Claudio; Gori, Monica

2013-01-01

Improving spatial ability of blind and visually impaired people is the main target of orientation and mobility (O&M) programs. In this study, we use a minimalistic mouse-shaped haptic device to show a new approach aimed at evaluating devices providing tactile representations of virtual objects. We consider psychophysical, behavioral, and subjective parameters to clarify under which circumstances mental representations of spaces (cognitive maps) can be efficiently constructed with touch by blindfolded sighted subjects. We study two complementary processes that determine map construction: low-level perception (in a passive stimulation task) and high-level information integration (in an active exploration task). We show that jointly considering a behavioral measure of information acquisition and a subjective measure of cognitive load can give an accurate prediction and a practical interpretation of mapping performance. Our simple TActile MOuse (TAMO) uses haptics to assess spatial ability: this may help individuals who are blind or visually impaired to be better evaluated by O&M practitioners or to evaluate their own performance.

The outcome of tactile touch on stress parameters in intensive care: a randomized controlled trial.

PubMed

Henricson, Maria; Ersson, Anders; Määttä, Sylvia; Segesten, Kerstin; Berglund, Anna-Lena

2008-11-01

The study aimed to investigate the effects of a five-day tactile touch intervention in order to find new and unconventional measures to moderate the detrimental influence of patients' stressors during intensive care. The hypothesis was that tactile touch would decrease stress indicators such as anxiety, glucose metabolism, blood pressure, heart rate and requirements of sedative drugs and noradrenalin. A randomized controlled trial was undertaken with 44 patients, which were assigned either to tactile touch or standard treatment (a rest hour). Observations of the stress indicators were made before, during and after the intervention or standard treatment. The study showed that tactile touch led to significantly lower levels of anxiety. The circulatory parameters suggested increased circulatory stability indicated by a reduction in noradrenalin requirement. The results need to be further validated through studies with larger sample sizes.

Intermodal Attention Shifts in Multimodal Working Memory.

PubMed

Katus, Tobias; Grubert, Anna; Eimer, Martin

2017-04-01

Attention maintains task-relevant information in working memory (WM) in an active state. We investigated whether the attention-based maintenance of stimulus representations that were encoded through different modalities is flexibly controlled by top-down mechanisms that depend on behavioral goals. Distinct components of the ERP reflect the maintenance of tactile and visual information in WM. We concurrently measured tactile (tCDA) and visual contralateral delay activity (CDA) to track the attentional activation of tactile and visual information during multimodal WM. Participants simultaneously received tactile and visual sample stimuli on the left and right sides and memorized all stimuli on one task-relevant side. After 500 msec, an auditory retrocue indicated whether the sample set's tactile or visual content had to be compared with a subsequent test stimulus set. tCDA and CDA components that emerged simultaneously during the encoding phase were consistently reduced after retrocues that marked the corresponding (tactile or visual) modality as task-irrelevant. The absolute size of cue-dependent modulations was similar for the tCDA/CDA components and did not depend on the number of tactile/visual stimuli that were initially encoded into WM. Our results suggest that modality-specific maintenance processes in sensory brain regions are flexibly modulated by top-down influences that optimize multimodal WM representations for behavioral goals.

Active tactile exploration using a brain-machine-brain interface.

PubMed

O'Doherty, Joseph E; Lebedev, Mikhail A; Ifft, Peter J; Zhuang, Katie Z; Shokur, Solaiman; Bleuler, Hannes; Nicolelis, Miguel A L

2011-10-05

Brain-machine interfaces use neuronal activity recorded from the brain to establish direct communication with external actuators, such as prosthetic arms. It is hoped that brain-machine interfaces can be used to restore the normal sensorimotor functions of the limbs, but so far they have lacked tactile sensation. Here we report the operation of a brain-machine-brain interface (BMBI) that both controls the exploratory reaching movements of an actuator and allows signalling of artificial tactile feedback through intracortical microstimulation (ICMS) of the primary somatosensory cortex. Monkeys performed an active exploration task in which an actuator (a computer cursor or a virtual-reality arm) was moved using a BMBI that derived motor commands from neuronal ensemble activity recorded in the primary motor cortex. ICMS feedback occurred whenever the actuator touched virtual objects. Temporal patterns of ICMS encoded the artificial tactile properties of each object. Neuronal recordings and ICMS epochs were temporally multiplexed to avoid interference. Two monkeys operated this BMBI to search for and distinguish one of three visually identical objects, using the virtual-reality arm to identify the unique artificial texture associated with each. These results suggest that clinical motor neuroprostheses might benefit from the addition of ICMS feedback to generate artificial somatic perceptions associated with mechanical, robotic or even virtual prostheses.

Investigation of the piezoelectric thimble tactile device operating modes.

PubMed

Bansevicius, Ramutis; Dragasius, Egidijus; Grigas, Vytautas; Jurenas, Vytautas; Mazeika, Darius; Zvironas, Arunas

2014-01-01

A multifunctional device to transfer graphical or text information for blind or visually impaired is presented. The prototype using tactile perception has been designed where information displayed on the screen of electronic device (mobile phone, PC) is transferred by oscillating needle, touching the fingertip. Having the aim to define optimal parameters of the fingertip excitation by needle, the computational analysis of different excitation modes has been carried out. A 3D solid computational finite element model of the skin segment, comprising four main fingertip skin layers (stratum corneum, epidermis, dermis and hypodermis) was built by using ANSYS Workbench FEA software. Harmonic analysis of its stress-strain state under excitation with different frequency (up to 10000 Hz) and harmonic force (0.01 N), acting outer stratum corneum layer in normal direction at one, two or three points has been performed. The influence of the mode of dynamic loading of skin was evaluated (in terms of the tactile signal level) on the basis of the normal and shear elastic strain in dermis, where mechanoreceptors are placed. It is shown that the tactile perception of information, delivered by three vibrating pins, may be influenced by configuration of excitation points (their number and phase of loading) and the frequency of excitation.

A systematic approach to the Kansei factors of tactile sense regarding the surface roughness.

PubMed

Choi, Kyungmee; Jun, Changrim

2007-01-01

Designing products to satisfy customers' emotion requires the information gathered through the human senses, which are visual, auditory, olfactory, gustatory, or tactile senses. By controlling certain design factors, customers' emotion can be evaluated, designed, and satisfied. In this study, a systematic approach is proposed to study the tactile sense regarding the surface roughness. Numerous pairs of antonymous tactile adjectives are collected and clustered. The optimal number of adjective clusters is estimated based on the several criterion functions. The representative average preferences of the final clusters are obtained as the estimates of engineering parameters to control the surface roughness of the commercial polymer-based products.

Seeing the Body Distorts Tactile Size Perception

ERIC Educational Resources Information Center

Longo, Matthew R.; Sadibolova, Renata

2013-01-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of…

Multisensory Motion Perception in 3–4 Month-Old Infants

PubMed Central

Nava, Elena; Grassi, Massimo; Brenna, Viola; Croci, Emanuela; Turati, Chiara

2017-01-01

Human infants begin very early in life to take advantage of multisensory information by extracting the invariant amodal information that is conveyed redundantly by multiple senses. Here we addressed the question as to whether infants can bind multisensory moving stimuli, and whether this occurs even if the motion produced by the stimuli is only illusory. Three- to 4-month-old infants were presented with two bimodal pairings: visuo-tactile and audio-visual. Visuo-tactile pairings consisted of apparently vertically moving bars (the Barber Pole illusion) moving in either the same or opposite direction with a concurrent tactile stimulus consisting of strokes given on the infant’s back. Audio-visual pairings consisted of the Barber Pole illusion in its visual and auditory version, the latter giving the impression of a continuous rising or ascending pitch. We found that infants were able to discriminate congruently (same direction) vs. incongruently moving (opposite direction) pairs irrespective of modality (Experiment 1). Importantly, we also found that congruently moving visuo-tactile and audio-visual stimuli were preferred over incongruently moving bimodal stimuli (Experiment 2). Our findings suggest that very young infants are able to extract motion as amodal component and use it to match stimuli that only apparently move in the same direction. PMID:29187829

A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar⁺ Ion Beam Treatment.

PubMed

Azkar Ul Hasan, Syed; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

2016-01-12

High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar⁺ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar⁺ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar⁺ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination.

Incrementally learning objects by touch: online discriminative and generative models for tactile-based recognition.

PubMed

Soh, Harold; Demiris, Yiannis

2014-01-01

Human beings not only possess the remarkable ability to distinguish objects through tactile feedback but are further able to improve upon recognition competence through experience. In this work, we explore tactile-based object recognition with learners capable of incremental learning. Using the sparse online infinite Echo-State Gaussian process (OIESGP), we propose and compare two novel discriminative and generative tactile learners that produce probability distributions over objects during object grasping/palpation. To enable iterative improvement, our online methods incorporate training samples as they become available. We also describe incremental unsupervised learning mechanisms, based on novelty scores and extreme value theory, when teacher labels are not available. We present experimental results for both supervised and unsupervised learning tasks using the iCub humanoid, with tactile sensors on its five-fingered anthropomorphic hand, and 10 different object classes. Our classifiers perform comparably to state-of-the-art methods (C4.5 and SVM classifiers) and findings indicate that tactile signals are highly relevant for making accurate object classifications. We also show that accurate "early" classifications are possible using only 20-30 percent of the grasp sequence. For unsupervised learning, our methods generate high quality clusterings relative to the widely-used sequential k-means and self-organising map (SOM), and we present analyses into the differences between the approaches.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

PubMed Central

Alfadhel, Ahmed; Khan, Mohammed Asadullah; Cardoso, Susana; Leitao, Diana; Kosel, Jürgen

2016-01-01

A magnetoresistive tactile sensor is reported, which is capable of working in high temperatures up to 140 °C. Hair-like bioinspired structures, known as cilia, made out of permanent magnetic nanocomposite material on top of spin-valve giant magnetoresistive (GMR) sensors are used for tactile sensing at high temperatures. The magnetic nanocomposite, consisting of iron nanowires incorporated into the polymer polydimethylsiloxane (PDMS), is very flexible, biocompatible, has high remanence, and is also resilient to antagonistic sensing ambient. When the cilia come in contact with a surface, they deflect in compliance with the surface topology. This yields a change of the GMR sensor signal, enabling the detection of extremely fine features. The spin-valve is covered with a passivation layer, which enables adequate performance in spite of harsh environmental conditions, as demonstrated in this paper for high temperature. PMID:27164113

Effect of systemic morphine on the responses of convergent neurons to noxious heat stimuli applied over graded surface areas.

PubMed

Gall, O; Bouhassira, D; Chitour, D; Le Bars, D

1999-04-01

Stimulus intensity is a major determinant of the antinociceptive activity of opiates. This study focused on the influence of the spatial characteristics of nociceptive stimuli, on opiate-induced depressions of nociceptive transmission at the level of the spinal cord. Anesthetized rats were prepared to allow extracellular recordings to be made from convergent neurons in the lumbar dorsal horn. The effects of systemic morphine (1 and 10 mg/kg) were compared with those of saline for thermal stimuli of constant intensity, applied to the area of skin surrounding the excitatory receptive field (1.9 cm2) or to a much larger adjacent area (18 cm2). The responses (mean +/- SD) elicited by the 1.9-cm2 stimulus were not modified by 1 mg/kg intravenous morphine, although they were decreased by the 10-mg/kg dose (to 11+/-4% of control values compared with saline; P < 0.05). In contrast, when the 18-cm2 stimulus was applied, 1 mg/kg intravenous morphine produced a paradoxical facilitation of the neuronal responses (159+/-36% of control values; P < 0.05) and 10 mg/kg intravenous morphine resulted in a weaker depression of the responses (to 42+/-24% of control values; P < 0.05) than was observed with the smaller stimulus. Doses of systemic morphine in the analgesic range for rats had dual effects on nociceptive transmission at the level of the spinal cord, depending on the surface area that was stimulated. Such effects are difficult to explain in terms of accepted pharmacodynamic concepts and may reflect an opioid-induced depression of descending inhibitory influences triggered by spatial summation.

Studies on adaptation to complete dentures. Part II: Oral stereognosis and tactile sensibility.

PubMed

Müller, F; Link, I; Fuhr, K; Utz, K H

1995-10-01

High oral perception is thought to contribute to poor adaptation to new dentures. The aim of this study was to evaluate the oral stereognosis and tactile sensibility in edentate subjects and relate these to patient age and capability of adaptation to new prostheses. A total of 67 patients were provided with new complete dentures 2-3 weeks before the experiment. In 54 subjects, the oral stereognosis was evaluated by 12 different test-pieces, which were placed unseen on the tongue and had to be recognized. In 38 patients, the oral tactile sensibility was determined in the premolar area using copper foils. The capability of adaptation was evaluated by a questionnaire. Denture retention was assessed by clinical examination. The number of correctly identified test-pieces and the average identification time were related to the age, but no relation was found to patients' capability of adaptation. The tactile sensibility was found to be impaired with age and diminished capability of adaptation. Both adaptation and oral tactile sensibility were significantly lower in subjects with poor lower-denture retention. In conclusion, the results cannot support a relationship between high oral stereognosis and adaptation problems. However, good denture retention facilitates the adaptation process.

An Evaluation of Substrates for Tactile Maps and Diagrams: Scanning Speed and Users' Preferences

ERIC Educational Resources Information Center

Jehoel, Sandra; Ungar, Simon; McCallum, Don; Rowell, Jonathan

2005-01-01

This study evaluated the relative suitability of a range of base materials for producing tactile maps and diagrams via a new ink-jet process. The visually impaired and sighted participants tactilely scanned arrays of symbols that were printed on seven substrate materials, including paper, plastic, and aluminum. In general, the rougher substrates…

Neurosurgical tactile discrimination training with haptic-based virtual reality simulation.

PubMed

Patel, Achal; Koshy, Nick; Ortega-Barnett, Juan; Chan, Hoi C; Kuo, Yong-Fan; Luciano, Cristian; Rizzi, Silvio; Matulyauskas, Martin; Kania, Patrick; Banerjee, Pat; Gasco, Jaime

2014-12-01

To determine if a computer-based simulation with haptic technology can help surgical trainees improve tactile discrimination using surgical instruments. Twenty junior medical students participated in the study and were randomized into two groups. Subjects in Group A participated in virtual simulation training using the ImmersiveTouch simulator (ImmersiveTouch, Inc., Chicago, IL, USA) that required differentiating the firmness of virtual spheres using tactile and kinesthetic sensation via haptic technology. Subjects in Group B did not undergo any training. With their visual fields obscured, subjects in both groups were then evaluated on their ability to use the suction and bipolar instruments to find six elastothane objects with areas ranging from 1.5 to 3.5 cm2 embedded in a urethane foam brain cavity model while relying on tactile and kinesthetic sensation only. A total of 73.3% of the subjects in Group A (simulation training) were able to find the brain cavity objects in comparison to 53.3% of the subjects in Group B (no training) (P  =  0.0183). There was a statistically significant difference in the total number of Group A subjects able to find smaller brain cavity objects (size ≤ 2.5 cm2) compared to that in Group B (72.5 vs. 40%, P  =  0.0032). On the other hand, no significant difference in the number of subjects able to detect larger objects (size ≧ 3 cm2) was found between Groups A and B (75 vs. 80%, P  =  0.7747). Virtual computer-based simulators with integrated haptic technology may improve tactile discrimination required for microsurgical technique.

Using a high spatial resolution tactile sensor for intention detection.

PubMed

Castellini, Claudio; Koiva, Risto

2013-06-01

Intention detection is the interpretation of biological signals with the aim of automatically, reliably and naturally understanding what a human subject desires to do. Although intention detection is not restricted to disabled people, such methods can be crucial in improving a patient's life, e.g., aiding control of a robotic wheelchair or of a self-powered prosthesis. Traditionally, intention detection is done using, e.g., gaze tracking, surface electromyography and electroencephalography. In this paper we present exciting initial results of an experiment aimed at intention detection using a high-spatial-resolution, high-dynamic-range tactile sensor. The tactile image of the ventral side of the forearm of 9 able-bodied participants was recorded during a variable-force task stimulated at the fingertip. Both the forces at the fingertip and at the forearm were synchronously recorded. We show that a standard dimensionality reduction technique (Principal Component Analysis) plus a Support Vector Machine attain almost perfect detection accuracy of the direction and the intensity of the intended force. This paves the way for high spatial resolution tactile sensors to be used as a means for intention detection.

Transfer of tactile perceptual learning to untrained neighboring fingers reflects natural use relationships

PubMed Central

Harrar, Vanessa; Oliver, Jonathan; Johansen-Berg, Heidi; Spence, Charles

2015-01-01

Tactile learning transfers from trained to untrained fingers in a pattern that reflects overlap between the representations of fingers in the somatosensory system (e.g., neurons with multifinger receptive fields). While physical proximity on the body is known to determine the topography of somatosensory representations, tactile coactivation is also an established organizing principle of somatosensory topography. In this study we investigated whether tactile coactivation, induced by habitual inter-finger cooperative use (use pattern), shapes inter-finger overlap. To this end, we used psychophysics to compare the transfer of tactile learning from the middle finger to its adjacent fingers. This allowed us to compare transfer to two fingers that are both physically and cortically adjacent to the middle finger but have differing use patterns. Specifically, the middle finger is used more frequently with the ring than with the index finger. We predicted this should lead to greater representational overlap between the former than the latter pair. Furthermore, this difference in overlap should be reflected in differential learning transfer from the middle to index vs. ring fingers. Subsequently, we predicted temporary learning-related changes in the middle finger's representation (e.g., cortical magnification) would cause transient interference in perceptual thresholds of the ring, but not the index, finger. Supporting this, longitudinal analysis revealed a divergence where learning transfer was fast to the index finger but relatively delayed to the ring finger. Our results support the theory that tactile coactivation patterns between digits affect their topographic relationships. Our findings emphasize how action shapes perception and somatosensory organization. PMID:26631145

Slanted joint axes of the stick insect antenna: an adaptation to tactile acuity

NASA Astrophysics Data System (ADS)

Mujagic, Samir; Krause, André F.; Dürr, Volker

2007-04-01

Like many flightless, obligatory walking insects, the stick insect Carausius morosus makes intensive use of active antennal movements for tactile near range exploration and orientation. The antennal joints of C. morosus have a peculiar oblique and non-orthogonal joint axis arrangement. Moreover, this arrangement is known to differ from that in crickets (Ensifera), locusts (Caelifera) and cockroaches (Blattodea), all of which have an orthogonal joint axis arrangement. Our hypothesis was that the situation found in C. morosus represents an important evolutionary trait of the order of stick and leaf insects (Phasmatodea). If this was true, it should be common to other species of the Phasmatodea. The objective of this comparative study was to resolve this question. We have measured the joint axis orientation of the head scape and scape pedicel joints along with other parameters that affect the tactile efficiency of the antenna. The obtained result was a complete kinematic description of the antenna. This was used to determine the size and location of kinematic out-of-reach zones, which are indicators of tactile acuity. We show that the oblique and non-orthogonal arrangement is common to eight species from six sub-families indicating that it is a synapomorphic character of the Euphasmatodea. This character can improve tactile acuity compared to the situation in crickets, locusts and cockroaches. Finally, because molecular data of a recent study indicate that the Phasmatodea may have evolved as flightless, obligatory walkers, we argue that the antennal joint axis arrangement of the Euphasmatodea reflects an evolutionary adaptation to tactile near range exploration during terrestrial locomotion.

Transfer of tactile perceptual learning to untrained neighboring fingers reflects natural use relationships.

PubMed

Dempsey-Jones, Harriet; Harrar, Vanessa; Oliver, Jonathan; Johansen-Berg, Heidi; Spence, Charles; Makin, Tamar R

2016-03-01

Tactile learning transfers from trained to untrained fingers in a pattern that reflects overlap between the representations of fingers in the somatosensory system (e.g., neurons with multifinger receptive fields). While physical proximity on the body is known to determine the topography of somatosensory representations, tactile coactivation is also an established organizing principle of somatosensory topography. In this study we investigated whether tactile coactivation, induced by habitual inter-finger cooperative use (use pattern), shapes inter-finger overlap. To this end, we used psychophysics to compare the transfer of tactile learning from the middle finger to its adjacent fingers. This allowed us to compare transfer to two fingers that are both physically and cortically adjacent to the middle finger but have differing use patterns. Specifically, the middle finger is used more frequently with the ring than with the index finger. We predicted this should lead to greater representational overlap between the former than the latter pair. Furthermore, this difference in overlap should be reflected in differential learning transfer from the middle to index vs. ring fingers. Subsequently, we predicted temporary learning-related changes in the middle finger's representation (e.g., cortical magnification) would cause transient interference in perceptual thresholds of the ring, but not the index, finger. Supporting this, longitudinal analysis revealed a divergence where learning transfer was fast to the index finger but relatively delayed to the ring finger. Our results support the theory that tactile coactivation patterns between digits affect their topographic relationships. Our findings emphasize how action shapes perception and somatosensory organization. Copyright © 2016 the American Physiological Society.

Posterior Thalamic Nucleus Modulation of Tactile Stimuli Processing in Rat Motor and Primary Somatosensory Cortices

PubMed Central

Casas-Torremocha, Diana; Clascá, Francisco; Núñez, Ángel

2017-01-01

Rodents move rhythmically their facial whiskers and compute differences between signals predicted and those resulting from the movement to infer information about objects near their head. These computations are carried out by a large network of forebrain structures that includes the thalamus and the primary somatosensory (S1BF) and motor (M1wk) cortices. Spatially and temporally precise mechanorreceptive whisker information reaches the S1BF cortex via the ventroposterior medial thalamic nucleus (VPM). Other whisker-related information may reach both M1wk and S1BF via the axons from the posterior thalamic nucleus (Po). However, Po axons may convey, in addition to direct sensory signals, the dynamic output of computations between whisker signals and descending motor commands. It has been proposed that this input may be relevant for adjusting cortical responses to predicted vs. unpredicted whisker signals, but the effects of Po input on M1wk and S1BF function have not been directly tested or compared in vivo. Here, using electrophysiology, optogenetics and pharmacological tools, we compared in adult rats M1wk and S1BF in vivo responses in the whisker areas of the motor and primary somatosensory cortices to passive multi-whisker deflection, their dependence on Po activity, and their changes after a brief intense activation of Po axons. We report that the latencies of the first component of tactile-evoked local field potentials in M1wk and S1BF are similar. The evoked potentials decrease markedly in M1wk, but not in S1BF, by injection in Po of the GABAA agonist muscimol. A brief high-frequency electrical stimulation of Po decreases the responsivity of M1wk and S1BF cells to subsequent whisker stimulation. This effect is prevented by the local application of omega-agatoxin, suggesting that it may in part depend on GABA release by fast-spiking parvalbumin (PV)-expressing cortical interneurons. Local optogenetic activation of Po synapses in different cortical layers also

Risk prediction and impaired tactile sensory perception among cancer patients during chemotherapy.

PubMed

Cardoso, Ana Carolina Lima Ramos; Araújo, Diego Dias de; Chianca, Tânia Couto Machado

2018-01-08

to estimate the prevalence of impaired tactile sensory perception, identify risk factors, and establish a risk prediction model among adult patients receiving antineoplastic chemotherapy. historical cohort study based on information obtained from the medical files of 127 patients cared for in the cancer unit of a private hospital in a city in Minas Gerais, Brazil. Data were analyzed using descriptive and bivariate statistics, with survival and multivariate analysis by Cox regression. 57% of the 127 patients included in the study developed impaired tactile sensory perception. The independent variables that caused significant impact, together with time elapsed from the beginning of treatment up to the onset of the condition, were: bone, hepatic and regional lymph node metastases; alcoholism; palliative chemotherapy; and discomfort in lower limbs. impaired tactile sensory perception was common among adult patients during chemotherapy, indicating the need to implement interventions designed for early identification and treatment of this condition.

The Influence of Tactile Cognitive Maps on Auditory Space Perception in Sighted Persons.

PubMed

Tonelli, Alessia; Gori, Monica; Brayda, Luca

2016-01-01

We have recently shown that vision is important to improve spatial auditory cognition. In this study, we investigate whether touch is as effective as vision to create a cognitive map of a soundscape. In particular, we tested whether the creation of a mental representation of a room, obtained through tactile exploration of a 3D model, can influence the perception of a complex auditory task in sighted people. We tested two groups of blindfolded sighted people - one experimental and one control group - in an auditory space bisection task. In the first group, the bisection task was performed three times: specifically, the participants explored with their hands the 3D tactile model of the room and were led along the perimeter of the room between the first and the second execution of the space bisection. Then, they were allowed to remove the blindfold for a few minutes and look at the room between the second and third execution of the space bisection. Instead, the control group repeated for two consecutive times the space bisection task without performing any environmental exploration in between. Considering the first execution as a baseline, we found an improvement in the precision after the tactile exploration of the 3D model. Interestingly, no additional gain was obtained when room observation followed the tactile exploration, suggesting that no additional gain was obtained by vision cues after spatial tactile cues were internalized. No improvement was found between the first and the second execution of the space bisection without environmental exploration in the control group, suggesting that the improvement was not due to task learning. Our results show that tactile information modulates the precision of an ongoing space auditory task as well as visual information. This suggests that cognitive maps elicited by touch may participate in cross-modal calibration and supra-modal representations of space that increase implicit knowledge about sound propagation.

A bio-injectable algin-aminocaproic acid thixogel with tri-stimuli responsiveness.

PubMed

Chejara, Dharmesh R; Mabrouk, Mostafa; Badhe, Ravindra V; Mulla, Jameel A S; Kumar, Pradeep; Choonara, Yahya E; du Toit, Lisa C; Pillay, Viness

2016-01-01

In this article a novel bio-injectable algin-aminocaproic acid (Alg-ACA) tri-stimuli responsive thixogel system is reported. The designed soft thixotrophic hydrogel (thixogel) was characterized using various analytical techniques such as FT-IR, NMR, SEM, AFM and DSC. The soft thixogel system was further investigated for stress responsiveness using different rheological studies which confirmed the thixotropic nature of the gel [Thixotropic area (Ar) of Alg-ACA (1:0.5), Alg-ACA (1:1) and Alg-ACA (1:2), were 23.5%, 43.1%, and 27.59%, respectively, which were higher than that of Na-Alg (2.08%)]. The thixogel also demonstrated temperature and ultrasonication responsiveness. This tri-stimuli responsive soft thixogel system was rendered flowable (fluid) on applying the described physical stimuli and recovered its "rigid" gel structure upon removal of the applied stimuli. This approach of synthesizing a thixogels may be applicable to a broad variety of other natural polymers and has the potential for use in biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Method and device for producing a tactile display using an electrorheological fluid

NASA Technical Reports Server (NTRS)

Garner, H. Douglas (Inventor)

1996-01-01

A tactile display device utilizes an electrorheological fluid to activate a plurality of tactile dots. A voltage is selectively produced uniformly across an electrorheological fluid flowing between a common ground electrode and a plurality of conductive dot electrodes, thereby producing an increase in the fluid's viscosity to the extent that fluid flow between the two electrodes is restricted. The flow restriction produces a build-up of electrorheological fluid in a corresponding dot actuator chamber. The resulting pressure increase in the chamber displaces an elastic diaphragm fixed to a display surface to form a lump which can be perceived by the reader as one dot in a Braille character cell. A flow regulation system provides a continually pressurized flow system and provides for free flow of the electrorheological fluid through the plurality of dot actuator chambers when they are not activated. The device is adaptable to printed circuit techniques and can simultaneously display tactile dots representative of a full page of Braille characters stored on a medium such as a tape cassette or to display tactile dots representative of non-Braille data appearing on a computer monitor or contained on another data storage medium. In an alternate embodiment, the elastic diaphragm drives a plurality of spring-loaded pins provided with positive stops to maintain consistent displacements of the pins in both their actuated and nonactuated positions.

Cassini Scientist for a Day: a tactile experience

NASA Astrophysics Data System (ADS)

Canas, L.; Altobelli, N.

2012-09-01

In September 2011, the Cassini spacecraft took images of three targets and a challenge was launched to all students: to choose the one target they thought would provide the best science and to write an essay explaining their reasons (more information on the "Cassini Scientist for a Day" essay contest official webpage in: http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/, run by NASA/JPL) The three targets presented were: Hyperion, Rhea and Titan, and Saturn. The idea behind "Cassini Scientist for a Day: a tactile experience" was to transform each of these images into schematic tactile images, highlighting relevant features apprehended through a tactile key, accompanied by a small text in Braille with some additional information. This initial approach would allow reach a broader community of students, more specifically those with visual impairment disabilities. Through proper implementation and careful study cases the adapted images associated with an explanatory key provide more resources in tactile astronomy. As the 2012 edition approaches a new set of targeted objet images will be once again transformed and adapted to visually impaired students and will aim to reach more students into participate in this international competition and to engage them in a quest to expand their knowledge in the amazing Cassini discoveries and the wonders of Saturn and its moons. As the winning essays will be published on the Cassini website and contest winners invited to participate in a dedicated teleconference with Cassini scientists from NASA's Jet Propulsion Laboratory, this initiative presents a great chance to all visually impaired students and teachers to participate in an exciting experience. These initiatives must be complemented with further information to strengthen the learning experience. However they stand as a good starting point to tackle further astronomical concepts in the classroom, especially this field that sometimes lacks the resources. Although

Detection of fever in children emergency care: comparisons of tactile and rectal temperatures in Nigerian children

PubMed Central

2010-01-01

Background Clinical thermometry is the objective method for temperature measurements but tactile assessment of fever at home is usually the basis for seeking medical attention especially where the cost and level of literacy preclude the use of thermometers. This study was carried out to determine the reliability of tactile perception of fever by caregivers, nurses and house physicians in comparison to rectal thermometry and also the use of commonly practiced surface of the hand in the care of ill children. All caregivers of children aged 6 to 59 months who presented to the emergency department were approached consecutively at the triage stage but 182 children participated. Each child had tactile assessment of fever using palmar and dorsal surfaces of the hand by the caregivers, House Physicians and Nursing Officers. Rectal temperature was also measured and read independently by nurses and house physicians. Comparisons were made between tactile assessments and thermometer readings using a cut-off for fever, 38.0°C and above. Findings The caregivers' perception of fever had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 95%, 23%, 66% and 73%, respectively compared with 93%, 26%, 67% and 69%, respectively for nursing officers. Irrespective of the groups studied, 77.1% of 336 assessors opined that the dorsal surface of the hand was more sensitive in tactile assessment of temperature and the frequently used site for assessment of fever were the head (35.6%) and neck (33.3%). Tactile assessment of temperature over-detected fever in ≥ 24% of cases among the three groups of assessors. Conclusions The present study suggests that tactile assessment of temperature may over estimate the prevalence of fever, it does not detect some cases and the need for objective measurement of temperature is emphasised in paediatric emergency care. PMID:20406473

Auditory Sensory Substitution is Intuitive and Automatic with Texture Stimuli

PubMed Central

Stiles, Noelle R. B.; Shimojo, Shinsuke

2015-01-01

Millions of people are blind worldwide. Sensory substitution (SS) devices (e.g., vOICe) can assist the blind by encoding a video stream into a sound pattern, recruiting visual brain areas for auditory analysis via crossmodal interactions and plasticity. SS devices often require extensive training to attain limited functionality. In contrast to conventional attention-intensive SS training that starts with visual primitives (e.g., geometrical shapes), we argue that sensory substitution can be engaged efficiently by using stimuli (such as textures) associated with intrinsic crossmodal mappings. Crossmodal mappings link images with sounds and tactile patterns. We show that intuitive SS sounds can be matched to the correct images by naive sighted participants just as well as by intensively-trained participants. This result indicates that existing crossmodal interactions and amodal sensory cortical processing may be as important in the interpretation of patterns by SS as crossmodal plasticity (e.g., the strengthening of existing connections or the formation of new ones), especially at the earlier stages of SS usage. An SS training procedure based on crossmodal mappings could both considerably improve participant performance and shorten training times, thereby enabling SS devices to significantly expand blind capabilities. PMID:26490260

Applied Computational Chemistry for the Blind and Visually Impaired

ERIC Educational Resources Information Center

Wedler, Henry B.; Cohen, Sarah R.; Davis, Rebecca L.; Harrison, Jason G.; Siebert, Matthew R.; Willenbring, Dan; Hamann, Christian S.; Shaw, Jared T.; Tantillo, Dean J.

2012-01-01

We describe accommodations that we have made to our applied computational-theoretical chemistry laboratory to provide access for blind and visually impaired students interested in independent investigation of structure-function relationships. Our approach utilizes tactile drawings, molecular model kits, existing software, Bash and Perl scripts…

Robot-Assisted Proprioceptive Training with Added Vibro-Tactile Feedback Enhances Somatosensory and Motor Performance.

PubMed

Cuppone, Anna Vera; Squeri, Valentina; Semprini, Marianna; Masia, Lorenzo; Konczak, Jürgen

2016-01-01

This study examined the trainability of the proprioceptive sense and explored the relationship between proprioception and motor learning. With vision blocked, human learners had to perform goal-directed wrist movements relying solely on proprioceptive/haptic cues to reach several haptically specified targets. One group received additional somatosensory movement error feedback in form of vibro-tactile cues applied to the skin of the forearm. We used a haptic robotic device for the wrist and implemented a 3-day training regimen that required learners to make spatially precise goal-directed wrist reaching movements without vision. We assessed whether training improved the acuity of the wrist joint position sense. In addition, we checked if sensory learning generalized to the motor domain and improved spatial precision of wrist tracking movements that were not trained. The main findings of the study are: First, proprioceptive acuity of the wrist joint position sense improved after training for the group that received the combined proprioceptive/haptic and vibro-tactile feedback (VTF). Second, training had no impact on the spatial accuracy of the untrained tracking task. However, learners who had received VTF significantly reduced their reliance on haptic guidance feedback when performing the untrained motor task. That is, concurrent VTF was highly salient movement feedback and obviated the need for haptic feedback. Third, VTF can be also provided by the limb not involved in the task. Learners who received VTF to the contralateral limb equally benefitted. In conclusion, somatosensory training can significantly enhance proprioceptive acuity within days when learning is coupled with vibro-tactile sensory cues that provide feedback about movement errors. The observable sensory improvements in proprioception facilitates motor learning and such learning may generalize to the sensorimotor control of the untrained motor tasks. The implications of these findings for

Good vibrations: tactile feedback in support of attention allocation and human-automation coordination in event-driven domains.

PubMed

Sklar, A E; Sarter, N B

1999-12-01

Observed breakdowns in human-machine communication can be explained, in part, by the nature of current automation feedback, which relies heavily on focal visual attention. Such feedback is not well suited for capturing attention in case of unexpected changes and events or for supporting the parallel processing of large amounts of data in complex domains. As suggested by multiple-resource theory, one possible solution to this problem is to distribute information across various sensory modalities. A simulator study was conducted to compare the effectiveness of visual, tactile, and redundant visual and tactile cues for indicating unexpected changes in the status of an automated cockpit system. Both tactile conditions resulted in higher detection rates for, and faster response times to, uncommanded mode transitions. Tactile feedback did not interfere with, nor was its effectiveness affected by, the performance of concurrent visual tasks. The observed improvement in task-sharing performance indicates that the introduction of tactile feedback is a promising avenue toward better supporting human-machine communication in event-driven, information-rich domains.

A Corticothalamic Circuit for Refining Tactile Encoding.

PubMed

Pauzin, François Philippe; Krieger, Patrik

2018-05-01

A fundamental task for the brain is to determine which aspects of the continuous flow of information is the most relevant in a given behavioral situation. The information flow is regulated via dynamic interactions between feedforward and feedback pathways. One such pathway is via corticothalamic feedback. Layer 6 (L6) corticothalamic (CT) cells make both cortical and thalamic connections and, therefore, are key modulators of activity in both areas. The functional properties of L6 CT cells in sensory processing were investigated in the mouse whisker system. Optogenetic activation of L6 CT neurons decreased spontaneous spiking, with the net effect that a whisker-evoked response was more accurately detected (larger evoked-to-spontaneous spiking ratio) but at the expense of reducing the response probability. In addition, L6 CT activation decreases sensory adaptation in both the thalamus and cortex. L6 CT activity can thus tune the tactile system, depending on the behaviorally relevant tactile input. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

U-shaped Relation between Prestimulus Alpha-band and Poststimulus Gamma-band Power in Temporal Tactile Perception in the Human Somatosensory Cortex.

PubMed

Wittenberg, Marc André; Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

2018-04-01

Neuronal oscillations are a ubiquitous phenomenon in the human nervous system. Alpha-band oscillations (8-12 Hz) have been shown to correlate negatively with attention and performance, whereas gamma-band oscillations (40-150 Hz) correlate positively. Here, we studied the relation between prestimulus alpha-band power and poststimulus gamma-band power in a suprathreshold tactile discrimination task. Participants received two electrical stimuli to their left index finger with different SOAs (0 msec, 100 msec, intermediate SOA, intermediate SOA ± 10 msec). The intermediate SOA was individually determined so that stimulation was bistable, and participants perceived one stimulus in half of the trials and two stimuli in the other half. We measured neuronal activity with magnetoencephalography (MEG). In trials with intermediate SOAs, behavioral performance correlated inversely with prestimulus alpha-band power but did not correlate with poststimulus gamma-band power. Poststimulus gamma-band power was high in trials with low and high prestimulus alpha-band power and low for intermediate prestimulus alpha-band power (i.e., U-shaped). We suggest that prestimulus alpha activity modulates poststimulus gamma activity and subsequent perception: (1) low prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that two stimuli were perceived; (2) intermediate prestimulus alpha-band power leads to low gamma-band power (interpreted as inefficient stimulus processing), consequently, perception was not biased in either direction; and (3) high prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that only one stimulus was perceived.

Auditory motion processing after early blindness

PubMed Central

Jiang, Fang; Stecker, G. Christopher; Fine, Ione

2014-01-01

Studies showing that occipital cortex responds to auditory and tactile stimuli after early blindness are often interpreted as demonstrating that early blind subjects “see” auditory and tactile stimuli. However, it is not clear whether these occipital responses directly mediate the perception of auditory/tactile stimuli, or simply modulate or augment responses within other sensory areas. We used fMRI pattern classification to categorize the perceived direction of motion for both coherent and ambiguous auditory motion stimuli. In sighted individuals, perceived motion direction was accurately categorized based on neural responses within the planum temporale (PT) and right lateral occipital cortex (LOC). Within early blind individuals, auditory motion decisions for both stimuli were successfully categorized from responses within the human middle temporal complex (hMT+), but not the PT or right LOC. These findings suggest that early blind responses within hMT+ are associated with the perception of auditory motion, and that these responses in hMT+ may usurp some of the functions of nondeprived PT. Thus, our results provide further evidence that blind individuals do indeed “see” auditory motion. PMID:25378368

Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound.

PubMed

Hoshi, T; Takahashi, M; Iwamoto, T; Shinoda, H

2010-01-01

This paper describes a tactile display which provides unrestricted tactile feedback in air without any mechanical contact. It controls ultrasound and produces a stress field in a 3D space. The principle is based on a nonlinear phenomenon of ultrasound: Acoustic radiation pressure. The fabricated prototype consists of 324 airborne ultrasound transducers, and the phase and intensity of each transducer are controlled individually to generate a focal point. The DC output force at the focal point is 16 mN and the diameter of the focal point is 20 mm. The prototype produces vibrations up to 1 kHz. An interaction system including the prototype is also introduced, which enables users to see and touch virtual objects.

When touch matters: an affective tactile intervention for older adults.

PubMed

Mammarella, Nicola; Fairfield, Beth; Di Domenico, Alberto

2012-10-01

Our goal was to test the hypothesis that positive tactile experiences can lead to an improvement in cognitive, emotional skills and perceived quality of life in a group of healthy community-dwelling older adults. During a 10-week period, older adults completed a series of activities that required manipulating either a piece of velvet, a piece of canvas or velcro. Only older adults who worked with velvet showed an increase in cognitive and emotional skills, and the perceived quality of life. Our study is one of the first to show that positive tactile experiences might have a beneficial effect on the psychological well-being of healthy community-dwelling older adults across different domains. © 2012 Japan Geriatrics Society.

Tactile cues can change movement: An example using tape to redistribute flexion from the lumbar spine to the hips and knees during lifting.

PubMed

Pinto, Brendan L; Beaudette, Shawn M; Brown, Stephen H M

2018-05-14

Given the appropriate cues, kinematic factors associated with low back injury risk and pain, such as spine flexion, can be avoided. Recent research has demonstrated the potential for tactile sensory information to change movement. In this study an athletic strapping tape was applied bilaterally along the lumbar extensor muscles to provide continuous tactile feedback information during a repeated lifting and lowering task. The presence of the tape resulted in a statistically significant reduction in lumbar spine flexion when compared to a baseline condition in which no tape was present. This reduction was further increased with the explicit instruction to pay attention to the sensations elicited by the tape. In both cases, the reduction in lumbar spine flexion was compensated for by increases in hip and knee flexion. When the tape was then removed and participants were instructed to continue lifting as if it was still present, the reduction in lumbar flexion and increases in hip and knee flexion were retained. Thus this study provides evidence that tactile cues can provide vital feedback information that can cue human lumbar spine movement to reduce kinematic factors associated with injury risk and pain. Copyright © 2018 Elsevier B.V. All rights reserved.

A case of cervico-brachial disorder due to tactile interpretation for deaf-blind persons.

PubMed

Kitahara, Teruyo; Nakamura, Kenji; Taoda, Kazushi; Shigeta, Hiromasa; Hirata, Mamoru

2012-01-01

We herein report a case of cervico-brachial disorder (CBD) due to long-term tactile interpreting. The patient was interviewed to investigate her past history, occupational history, work conditions and clinical course in detail. The case was diagnosed in accordance with the "Diagnostic Criteria for CBD 2007" established by the Research Association for CBD of the Japanese Society for Occupational Health. The patient was a 49-year-old female who has worked as a regular occupational instructor at a welfare work activity center for deaf people since April 22, 2010. Her primary job is to instruct and aid others in learning confectionery manufacturing and coffee shop tasks. She also performs tactile interpreting for two deaf-blind workers during a morning health check and during any meetings. On September 3, 2010, she interpreted by tactile signing for about three hours alone during a meeting, due to the absence of other interpreters. She developed severe pain in her back immediately after carrying out this interpretation, and the pain thereafter continued and developed in the upper extremities. She was diagnosed with a severe and prolonged case of the non-specific type of CBD. Interpretation by tactile signing may impose a heavier burden on the upper extremities, shoulders and neck than that imposed by common sign language. A shorter time of interpretation, ensuring the availability of rest time and supporting tools or methods for the upper extremities, are therefore considered to be necessary to prevent the incidence of CBD among interpreters using tactile signing.

Tactile discrimination activates the visual cortex of the recently blind naive to Braille: a functional magnetic resonance imaging study in humans.

PubMed

Sadato, Norihiro; Okada, Tomohisa; Kubota, Kiyokazu; Yonekura, Yoshiharu

2004-04-08

The occipital cortex of blind subjects is known to be activated during tactile discrimination tasks such as Braille reading. To investigate whether this is due to long-term learning of Braille or to sensory deafferentation, we used fMRI to study tactile discrimination tasks in subjects who had recently lost their sight and never learned Braille. The occipital cortex of the blind subjects without Braille training was activated during the tactile discrimination task, whereas that of control sighted subjects was not. This finding suggests that the activation of the visual cortex of the blind during performance of a tactile discrimination task may be due to sensory deafferentation, wherein a competitive imbalance favors the tactile over the visual modality.

Intuitive tactile zooming for graphics accessed by individuals who are blind and visually impaired.

PubMed

Rastogi, Ravi; Pawluk, T V Dianne; Ketchum, Jessica

2013-07-01

One possibility of providing access to visual graphics for those who are visually impaired is to present them tactually: unfortunately, details easily available to vision need to be magnified to be accessible through touch. For this, we propose an "intuitive" zooming algorithm to solve potential problems with directly applying visual zooming techniques to haptic displays that sense the current location of a user on a virtual diagram with a position sensor and, then, provide the appropriate local information either through force or tactile feedback. Our technique works by determining and then traversing the levels of an object tree hierarchy of a diagram. In this manner, the zoom steps adjust to the content to be viewed, avoid clipping and do not zoom when no object is present. The algorithm was tested using a small, "mouse-like" display with tactile feedback on pictures representing houses in a community and boats on a lake. We asked the users to answer questions related to details in the pictures. Comparing our technique to linear and logarithmic step zooming, we found a significant increase in the correctness of the responses (odds ratios of 2.64:1 and 2.31:1, respectively) and usability (differences of 36% and 19%, respectively) using our "intuitive" zooming technique.

[Effects of visual optical stimuli for accommodation-convergence system on asthenopia].

PubMed

Iwasaki, Tsuneto; Tawara, Akihiko; Miyake, Nobuyuki

2006-01-01

We investigated the effect on eyestrain of optical stimuli that we designed for accommodation and convergence systems. Eight female students were given optical stimuli for accommodation and convergence systems for 1.5 min immediately after 20 min of a sustained task on a 3-D display. Before and after the trial, their ocular functions were measured and their symptoms were assessed. The optical stimuli were applied by moving targets of scenery images far and near around the far point position of both eyes on a horizonal place, which induced divergence in the direction of the eye position of rest. In a control group, subjects rested with closed eyes for 1.5 min instead of applying the optical stimuli. There were significant changes in the accommodative contraction time (from far to near) and the accommodative relaxation time (from near to far) and the lag of accommodation at near target, from 1.26 s to 1.62 s and from 1.49 s to 1.63 s and from 0.5 D to 0.65 D, respectively, and in the symptoms in the control group after the duration of closed-eye rest. In the stimulus group, however, the changes of those functions were smaller than in the control group. From these results, we suggest that our designed optical stimuli for accommodation and convergence systems are effective on asthenopia following accommodative dysfunction.

Consistency of Border-Ownership Cells across Artificial Stimuli, Natural Stimuli, and Stimuli with Ambiguous Contours.

PubMed

Hesse, Janis K; Tsao, Doris Y

2016-11-02

Segmentation and recognition of objects in a visual scene are two problems that are hard to solve separately from each other. When segmenting an ambiguous scene, it is helpful to already know the present objects and their shapes. However, for recognizing an object in clutter, one would like to consider its isolated segment alone to avoid confounds from features of other objects. Border-ownership cells (Zhou et al., 2000) appear to play an important role in segmentation, as they signal the side-of-figure of artificial stimuli. The present work explores the role of border-ownership cells in dorsal macaque visual areas V2 and V3 in the segmentation of natural object stimuli and locally ambiguous stimuli. We report two major results. First, compared with previous estimates, we found a smaller percentage of cells that were consistent across artificial stimuli used previously. Second, we found that the average response of those neurons that did respond consistently to the side-of-figure of artificial stimuli also consistently signaled, as a population, the side-of-figure for borders of single faces, occluding faces and, with higher latencies, even stimuli with illusory contours, such as Mooney faces and natural faces completely missing local edge information. In contrast, the local edge or the outlines of the face alone could not always evoke a significant border-ownership signal. Our results underscore that border ownership is coded by a population of cells, and indicate that these cells integrate a variety of cues, including low-level features and global object context, to compute the segmentation of the scene. To distinguish different objects in a natural scene, the brain must segment the image into regions corresponding to objects. The so-called "border-ownership" cells appear to be dedicated to this task, as they signal for a given edge on which side the object is that owns it. Here, we report that individual border-ownership cells are unreliable when tested across

Greater tactile sensitivity and less use of immature psychological defense mechanisms predict women's penile-vaginal intercourse orgasm.

PubMed

Brody, Stuart; Houde, Stephanie; Hess, Ursula

2010-09-01

Previous research has suggested that diminished tactile sensitivity might be associated with reduced sexual activity and function. Research has also demonstrated significant physiological and psychological differences between sexual behaviors, including immature psychological defense mechanisms (associated with various psychopathologies) impairing specifically women's orgasm from penile-vaginal intercourse (PVI). To examine the extent to which orgasm triggered by PVI (distinguished from other sexual activities) is associated with both greater tactile sensitivity and lesser use of immature psychological defenses. Seventy French-Canadian female university students (aged 18-30) had their finger sensitivity measured with von Frey type microfilaments, completed the Defense Style Questionnaire and a short form of the Marlowe-Crowne social desirability scale, and provided details of the 1 month (and ever) frequencies of engaging in, and having an orgasm from, PVI, masturbation, anal intercourse, partner masturbation, and cunnilingus. Logistic and linear regression prediction of orgasm triggered by PVI from tactile sensitivity, age, social desirability responding, and immature psychological defenses. Having a PVI orgasm in the past month was associated with greater tactile sensitivity (odds ratio=4.0 for each filament point) and less use of immature defense mechanisms (odds ratio=5.1 for each scale point). Lifetime PVI orgasm was associated only with less use of immature defense mechanisms (and lower social desirability responding score). Orgasms triggered by other activities were not associated with either tactile sensitivity or immature defense mechanisms. Tactile sensitivity was also associated with greater past month PVI frequency (inclusion of PVI frequency in a logistic regression model displaced tactile sensitivity), and lesser use of immature defenses was associated with greater past month PVI and PVI orgasm frequencies. Both diminished physical sensitivity and the

Application of tactile/kinesthetic stimulation in preterm infants: a systematic review.

PubMed

Pepino, Vanessa C; Mezzacappa, Maria Aparecida

2015-01-01

To verify the methods used by the clinical trials that assessed the effect of tactile/kinesthetic stimulation on weight gain in preterm infants and highlight the similarities and differences among such studies. This review collected studies from two databases, PEDro and PubMed, in July of 2014, in addition to bibliographies. Two researchers assessed the relevant titles independently, and then chose which studies to read in full and include in this review by consensus. Clinical trials that studied tactile stimulation or massage therapy whether or not associated with kinesthetic stimulation of preterm infants; that assessed weight gain after the intervention; that had a control group and were composed in English, Portuguese, or Spanish were included. A total of 520 titles were found and 108 were selected for manuscript reading. Repeated studies were excluded, resulting in 40 different studies. Of these, 31 met all the inclusion criteria. There were many differences in the application of tactile/kinesthetic stimulation techniques among studies, which hindered the accurate reproduction of the procedure. Also, many studies did not describe the adverse events that occurred during stimulation, the course of action taken when such events occurred, and their effect on the outcome. These studies made a relevant contribution towards indicating tactile/kinesthetic stimulation as a promising tool. Nevertheless, there was no standard for application among them. Future studies should raise the level of methodological rigor and describe the adverse events. This may permit other researchers to be more aware of expected outcomes, and a standard technique could be established. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

A Computational Model of a Descending Mechanosensory Pathway Involved in Active Tactile Sensing

PubMed Central

Ache, Jan M.; Dürr, Volker

2015-01-01

Many animals, including humans, rely on active tactile sensing to explore the environment and negotiate obstacles, especially in the dark. Here, we model a descending neural pathway that mediates short-latency proprioceptive information from a tactile sensor on the head to thoracic neural networks. We studied the nocturnal stick insect Carausius morosus, a model organism for the study of adaptive locomotion, including tactually mediated reaching movements. Like mammals, insects need to move their tactile sensors for probing the environment. Cues about sensor position and motion are therefore crucial for the spatial localization of tactile contacts and the coordination of fast, adaptive motor responses. Our model explains how proprioceptive information about motion and position of the antennae, the main tactile sensors in insects, can be encoded by a single type of mechanosensory afferents. Moreover, it explains how this information is integrated and mediated to thoracic neural networks by a diverse population of descending interneurons (DINs). First, we quantified responses of a DIN population to changes in antennal position, motion and direction of movement. Using principal component (PC) analysis, we find that only two PCs account for a large fraction of the variance in the DIN response properties. We call the two-dimensional space spanned by these PCs ‘coding-space’ because it captures essential features of the entire DIN population. Second, we model the mechanoreceptive input elements of this descending pathway, a population of proprioceptive mechanosensory hairs monitoring deflection of the antennal joints. Finally, we propose a computational framework that can model the response properties of all important DIN types, using the hair field model as its only input. This DIN model is validated by comparison of tuning characteristics, and by mapping the modelled neurons into the two-dimensional coding-space of the real DIN population. This reveals the