Tactile friction of topical formulations.

Science.gov (United States)

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.

Tactile object exploration using cursor navigation sensors

DEFF Research Database (Denmark)

Kraft, Dirk; Bierbaum, Alexander; Kjaergaard, Morten

2009-01-01

In robotic applications tactile sensor systems serve the purpose of localizing a contact point and measuring contact forces. We have investigated the applicability of a sensorial device commonly used in cursor navigation technology for tactile sensing in robotics. We show the potential of this se......In robotic applications tactile sensor systems serve the purpose of localizing a contact point and measuring contact forces. We have investigated the applicability of a sensorial device commonly used in cursor navigation technology for tactile sensing in robotics. We show the potential...... of this sensor for active haptic exploration. More specifically, we present experiments and results which demonstrate the extraction of relevant object properties such as local shape, weight and elasticity using this technology. Besides its low price due to mass production and its modularity, an interesting...... aspect of this sensor is that beside a localization of contact points and measurement of the contact normal force also shear forces can be measured. This is relevant for many applications such as surface normal estimation and weight measurements. Scalable tactile sensor arrays have been developed...

Fundamental study on formulation design of skin care products by modeling of tactile sensation.

Science.gov (United States)

Akiyama, Yoko; Mishima, Fumihito; Nishijima, Shigehiro

2013-01-01

The objective of this study is to construct a method to quantify and formulate the human tactile sensation. We have tried to indicate the sensory scores of tactile sensation as a combination of the physical values of skin care products. Consequently, the extracted principle factors of the sensory properties could be related to the physical values by multiple regression analysis. For the next step, we investigated the physical mechanism of tactile sensation, and proposed a method to formulate the sensory properties. A method to formulate the sensory properties of skin care products was constructed based on the relation between sensory values, principal factors, physical values and composition. The method was verified by sensory evaluation.

Diagnostic value of the near-nerve needle sensory nerve conduction in sensory inflammatory demyelinating polyneuropathy.

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Odabasi, Zeki; Oh, Shin J

2018-03-01

In this study we report the diagnostic value of the near-nerve needle sensory nerve conduction study (NNN-SNCS) in sensory inflammatory demyelinating polyneuropathy (IDP) in which the routine nerve conduction study was normal or non-diagnostic. The NNN-SNCS was performed to identify demyelination in the plantar nerves in 14 patients and in the median or ulnar nerve in 2 patients with sensory IDP. In 16 patients with sensory IDP, routine NCSs were either normal or non-diagnostic for demyelination. Demyelination was identified by NNN-SNCS by dispersion and/or slow nerve conduction velocity (NCV) below the demyelination marker. Immunotherapy was initiated in 11 patients, 10 of whom improved or remained stable. NNN-SNCS played an essential role in identifying demyelinaton in 16 patients with sensory IDP, leading to proper treatment. Muscle Nerve 57: 414-418, 2018. © 2017 Wiley Periodicals, Inc.

About Face: Evaluating and Managing Tactile Impairment at the Time of Autism Diagnosis

OpenAIRE

Silva, Louisa M. T.; Schalock, Mark; Gabrielsen, Kristen R.

2015-01-01

Evaluation for sensory impairment is a routine part of autism diagnosis. Sensory impairment of hearing, vision, or touch results in developmental delay and must be addressed before delay can resolve. Recent studies confirm that tactile impairment is present in autism and can be effectively treated with a tactile stimulation protocol. The research suggests a change in management at the time of autism diagnosis to include evaluation and treatment of tactile impairment. Here we validate screenin...

Bodily illusions disrupt tactile sensations.

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D'Amour, Sarah; Pritchett, Lisa M; Harris, Laurence R

2015-02-01

To accurately interpret tactile information, the brain needs to have an accurate representation of the body to which to refer the sensations. Despite this, body representation has only recently been incorporated into the study of tactile perception. Here, we investigate whether distortions of body representation affect tactile sensations. We perceptually altered the length of the arm and the width of the waist using a tendon vibration illusion and measured spatial acuity and sensitivity. Surprisingly, we found reduction in both tactile acuity and sensitivity thresholds when the arm or waist was perceptually altered, which indicates a general disruption of low-level tactile processing. We postulate that the disruptive changes correspond to the preliminary stage as the body representation starts to change and may give new insights into sensory processing in people with long-term or sudden abnormal body representation such as are found in eating disorders or following amputation.

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

Science.gov (United States)

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%.

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

Directory of Open Access Journals (Sweden)

Iza Husna Mohamad Hashim

2017-11-01

Full Text Available 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%.

Motor-sensory confluence in tactile perception.

Science.gov (United States)

Saig, Avraham; Gordon, Goren; Assa, Eldad; Arieli, Amos; Ahissar, Ehud

2012-10-03

Perception involves motor control of sensory organs. However, the dynamics underlying emergence of perception from motor-sensory interactions are not yet known. Two extreme possibilities are as follows: (1) motor and sensory signals interact within an open-loop scheme in which motor signals determine sensory sampling but are not affected by sensory processing and (2) motor and sensory signals are affected by each other within a closed-loop scheme. We studied the scheme of motor-sensory interactions in humans using a novel object localization task that enabled monitoring the relevant overt motor and sensory variables. We found that motor variables were dynamically controlled within each perceptual trial, such that they gradually converged to steady values. Training on this task resulted in improvement in perceptual acuity, which was achieved solely by changes in motor variables, without any change in the acuity of sensory readout. The within-trial dynamics is captured by a hierarchical closed-loop model in which lower loops actively maintain constant sensory coding, and higher loops maintain constant sensory update flow. These findings demonstrate interchangeability of motor and sensory variables in perception, motor convergence during perception, and a consistent hierarchical closed-loop perceptual model.

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

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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.

Visual Sensory Signals Dominate Tactile Cues during Docked Feeding in Hummingbirds.

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Goller, Benjamin; Segre, Paolo S; Middleton, Kevin M; Dickinson, Michael H; Altshuler, Douglas L

2017-01-01

Animals living in and interacting with natural environments must monitor and respond to changing conditions and unpredictable situations. Using information from multiple sensory systems allows them to modify their behavior in response to their dynamic environment but also creates the challenge of integrating different, and potentially contradictory, sources of information for behavior control. Understanding how multiple information streams are integrated to produce flexible and reliable behavior is key to understanding how behavior is controlled in natural settings. Natural settings are rarely still, which challenges animals that require precise body position control, like hummingbirds, which hover while feeding from flowers. Tactile feedback, available only once the hummingbird is docked at the flower, could provide additional information to help maintain its position at the flower. To investigate the role of tactile information for hovering control during feeding, we first asked whether hummingbirds physically interact with a feeder once docked. We quantified physical interactions between docked hummingbirds and a feeder placed in front of a stationary background pattern. Force sensors on the feeder measured a complex time course of loading that reflects the wingbeat frequency and bill movement of feeding hummingbirds, and suggests that they sometimes push against the feeder with their bill. Next, we asked whether the measured tactile interactions were used by feeding hummingbirds to maintain position relative to the feeder. We created two experimental scenarios-one in which the feeder was stationary and the visual background moved and the other where the feeder moved laterally in front of a white background. When the visual background pattern moved, docked hummingbirds pushed significantly harder in the direction of horizontal visual motion. When the feeder moved, and the background was stationary, hummingbirds generated aerodynamic force in the opposite

Early postnatal development of electrophysiological and histological properties of sensory sural nerves in male rats that were maternally deprived and artificially reared: Role of tactile stimulation.

Science.gov (United States)

Zempoalteca, Rene; Porras, Mercedes G; Moreno-Pérez, Suelem; Ramirez-Funez, Gabriela; Aguirre-Benítez, Elsa L; González Del Pliego, Margarita; Mariscal-Tovar, Silvia; Mendoza-Garrido, Maria E; Hoffman, Kurt Leroy; Jiménez-Estrada, Ismael; Melo, Angel I

2018-04-01

Early adverse experiences disrupt brain development and behavior, but little is known about how such experiences impact on the development of the peripheral nervous system. Recently, we found alterations in the electrophysiological and histological characteristics of the sensory sural (SU) nerve in maternally deprived, artificially reared (AR) adult male rats, as compared with maternally reared (MR) control rats. In the present study, our aim was to characterize the ontogeny of these alterations. Thus, male pups of four postnatal days (PND) were (1) AR group, (2) AR and received daily tactile stimulation to the body and anogenital region (AR-Tactile group); or (3) reared by their mother (MR group). At PND 7, 14, or 21, electrophysiological properties and histological characteristics of the SU nerves were assessed. At PND 7, the electrophysiological properties and most histological parameters of the SU nerve did not differ among MR, AR, and AR-Tactile groups. By contrast, at PND 14 and/or 21, the SU nerve of AR rats showed a lower CAP amplitude and area, and a significant reduction in myelin area and myelin thickness, which were accompanied by a reduction in axon area (day 21 only) compared to the nerves of MR rats. Tactile stimulation (AR-Tactile group) partially prevented most of these alterations. These results suggest that sensory cues from the mother and/or littermates during the first 7-14 PND are relevant for the proper development and function of the adult SU nerve. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 351-362, 2018. © 2017 Wiley Periodicals, Inc.

About Face: Evaluating and Managing Tactile Impairment at the Time of Autism Diagnosis

Directory of Open Access Journals (Sweden)

Louisa M. T. Silva

2015-01-01

Full Text Available Evaluation for sensory impairment is a routine part of autism diagnosis. Sensory impairment of hearing, vision, or touch results in developmental delay and must be addressed before delay can resolve. Recent studies confirm that tactile impairment is present in autism and can be effectively treated with a tactile stimulation protocol. The research suggests a change in management at the time of autism diagnosis to include evaluation and treatment of tactile impairment. Here we validate screening and management tool for tactile impairment, the Autism Touch and Self-Regulation Checklist, in 404 typical and autistic preschool children. The tool assesses tactile impairment by location and severity. Autistic children were distinguished by mixed pain and numbness on multiple areas including the face and mouth (F=412.1 (1,402;p<.000. Oral-facial tactile impairment interferes with the tactile stimulus to orienting. We hypothesized that oral-facial tactile impairment and difficulty orienting are predictive of ASD and that severity of tactile impairment is predictive of severity of ASD. Questions evaluating oral-facial and orienting responses correctly predicted 91% of the autism group. Severity of tactile impairment correctly predicted 81% of mild versus severe ASD. Results underscore the importance of evaluating and treating tactile impairment at the time of autism diagnosis.

The phase of prestimulus alpha oscillations affects tactile perception.

Science.gov (United States)

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.

Tactile-Sight: A Sensory Substitution Device Based on Distance-Related Vibrotactile Flow

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Leandro Cancar

2013-06-01

Full Text Available Sensory substitution is a research field of increasing interest with regard to technical, applied and theoretical issues. Among the latter, it is of central interest to understand the form in which humans perceive the environment. Ecological psychology, among other approaches, proposes that we can detect higher-order informational variables (in the sense that they are defined over substantial spatial and temporal intervals that specify our interaction with the environment. When using a vibrotactile sensory substitution device, it is reasonable to ask if stimulation on the skin may be exploitable to detect higher-order variables. Motivated by this question, a portable vibrotactile sensory substitution device was built, using distance-based information as a source and driving a large number of vibrotactile actuators (72 in the reported version, 120 max. The portable device was designed to explore real environments, allowing natural unrestricted movement for the user while providing contingent real-time vibrotactile information. Two preliminary experiments were performed. In the first one, participants were asked to detect the time to contact of an approaching ball in a simulated (desktop environment. Reasonable performance was observed in all experimental conditions, including the one with only tactile stimulation. In the second experiment, a portable version of the device was used in a real environment, where participants were asked to hit an approaching ball. Participants were able to coordinate their arm movements with vibrotactile stimulation in appropriate timing. We conclude that vibrotactile flow can be generated by distance-based activation of the actuators and that this stimulation on the skin allows users to perceive time-to-contact related environmental properties.

Tactile Perception in Adults with Autism: A Multidimensional Psychophysical Study

Science.gov (United States)

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…

Attention modulates sensory suppression during back movements.

Science.gov (United States)

Van Hulle, Lore; Juravle, Georgiana; Spence, Charles; Crombez, Geert; Van Damme, Stefaan

2013-06-01

Tactile perception is often impaired during movement. The present study investigated whether such sensory suppression also occurs during back movements, and whether this would be modulated by attention. In two tactile detection experiments, participants simultaneously engaged in a movement task, in which they executed a back-bending movement, and a perceptual task, consisting of the detection of subtle tactile stimuli administered to their upper or lower back. The focus of participants' attention was manipulated by raising the probability that one of the back locations would be stimulated. The results revealed that tactile detection was suppressed during the execution of the back movements. Furthermore, the results of Experiment 2 revealed that when the stimulus was always presented to the attended location, tactile suppression was substantially reduced, suggesting that sensory suppression can be modulated by top-down attentional processes. The potential of this paradigm for studying tactile information processing in clinical populations is discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

Inducing circular vection with tactile stimulation encircling the waist

NARCIS (Netherlands)

Tinga, A.M.; Jansen, C.; Smagt, M.J. van der; Nijboer, T.C.W.; Erp, J.B.F. van

2018-01-01

In general, moving sensory stimuli (visual and auditory) can induce illusory sensations of self-motion (i.e. vection) in the direction opposite of the sensory stimulation. The aim of the current study was to examine whether tactile stimulation encircling the waist could induce circular vection

A critical experimental study of the classical tactile threshold theory

Directory of Open Access Journals (Sweden)

Medina Leonel E

2010-06-01

Full Text Available Abstract Background The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychophysical experimental results such as in stochastic resonance (SR phenomena. In SR, noise enhances detection of sub-threshold stimuli and the phenomenon is explained stating that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. We designed an experiment to test the validity of the classical vibrotactile threshold. Using a second choice experiment, we show that individuals can order sensorial events below the level known as the classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level contradicting the definition of the classical tactile threshold. Results We performed a three alternative forced choice detection experiment on 6 subjects asking them first and second choices. In each trial, only one of the intervals contained a stimulus and the others contained only noise. According to the classical threshold assumptions, a correct second choice response corresponds to a guess attempt with a statistical frequency of 50%. Results show an average of 67.35% (STD = 1.41% for the second choice response that is not explained by the classical threshold definition. Additionally, for low stimulus amplitudes, second choice correct detection is above chance level for any detectability level. Conclusions Using a second choice experiment, we show that individuals can order sensorial events below the level known as a classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance

Verification and clarification of patterns of sensory integrative dysfunction.

Science.gov (United States)

Mailloux, Zoe; Mulligan, Shelley; Roley, Susanne Smith; Blanche, Erna; Cermak, Sharon; Coleman, Gina Geppert; Bodison, Stefanie; Lane, Christianne Joy

2011-01-01

Building on established relationships between the constructs of sensory integration in typical and special needs populations, in this retrospective study we examined patterns of sensory integrative dysfunction in 273 children ages 4-9 who had received occupational therapy evaluations in two private practice settings. Test results on the Sensory Integration and Praxis Tests, portions of the Sensory Processing Measure representing tactile overresponsiveness, and parent report of attention and activity level were included in the analyses. Exploratory factor analysis identified patterns similar to those found in early studies by Ayres (1965, 1966a, 1966b, 1969, 1972b, 1977, & 1989), namely Visuodyspraxia and Somatodyspraxia, Vestibular and Proprioceptive Bilateral Integration and Sequencing, Tactile and Visual Discrimination, and Tactile Defensiveness and Attention. Findings reinforce associations between constructs of sensory integration and assist with understanding sensory integration disorders that may affect childhood occupation. Limitations include the potential for subjective interpretation in factor analysis and inability to adjust measures available in charts in a retrospective research.

Audio-tactile integration and the influence of musical training.

Science.gov (United States)

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.

Audio-tactile integration and the influence of musical training.

Directory of Open Access Journals (Sweden)

Anja Kuchenbuch

Full Text Available 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.

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

Science.gov (United States)

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.

A case of tactile agnosia with a lesion restricted to the post-central gyrus.

Science.gov (United States)

Estañol, Bruno; Baizabal-Carvallo, José Fidel; Sentíes-Madrid, Horacio

2008-01-01

Tactile agnosia has been described after lesions of the primary sensory cortex but the exact location and extension of those lesions is not clear. We report the clinical features and imaging findings in a patient with an acute ischemic stroke restricted to the primary sensory area (S1). A 73-year-old man had a sudden onset of a left alien hand, without left hemiparesis. Neurological examination showed intact primary sensory functions, but impaired recognition of shape, size (macrogeometrical) and texture (microgeometrical) of objects; damage confined to the post-central gyrus, sparing the posterior parietal cortex was demonstrated on MRI. An embolic occlusion of the anterior parietal artery was suspected as mechanism of stroke. Tactile agnosia with impaired microgeometrical and macrogeometrical features' recognition can result from a single lesion in the primary sensory cortex (S1) in the right parietal hemisphere, sparing other regions of the cerebral cortex which presumably participate in tactile object recognition.

Tactile exploration of virtual objects for blind and sighted people: the role of beta 1 EEG band in sensory substitution and supramodal mental mapping.

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Campus, C; Brayda, L; De Carli, F; Chellali, R; Famà, F; Bruzzo, C; Lucagrossi, L; Rodriguez, G

2012-05-01

The neural correlates of exploration and cognitive mapping in blindness remain elusive. The role of visuo-spatial pathways in blind vs. sighted subjects is still under debate. In this preliminary study, we investigate, as a possible estimation of the activity in the visuo-spatial pathways, the EEG patterns of blind and blindfolded-sighted subjects during the active tactile construction of cognitive maps from virtual objects compared with rest and passive tactile stimulation. Ten blind and ten matched, blindfolded-sighted subjects participated in the study. Events were defined as moments when the finger was only stimulated (passive stimulation) or the contour of a virtual object was touched (during active exploration). Event-related spectral power and coherence perturbations were evaluated within the beta 1 band (14-18 Hz). They were then related to a subjective cognitive-load estimation required by the explorations [namely, perceived levels of difficulty (PLD)]. We found complementary cues for sensory substitution and spatial processing in both groups: both blind and sighted subjects showed, while exploring, late power decreases and early power increases, potentially associated with motor programming and touch, respectively. The latter involved occipital areas only for blind subjects (long-term plasticity) and only during active exploration, thus supporting tactile-to-visual sensory substitution. In both groups, coherences emerged among the fronto-central, centro-parietal, and occipito-temporal derivations associated with visuo-spatial processing. This seems in accordance with mental map construction involving spatial processing, sensory-motor processing, and working memory. The observed involvement of the occipital regions suggests that a substitution process also occurs in sighted subjects. Only during explorations did coherence correlate positively with PLD for both groups and in derivations, which can be related to visuo-spatial processing, supporting the

Tactile exploration of virtual objects for blind and sighted people: the role of beta 1 EEG band in sensory substitution and supramodal mental mapping

Science.gov (United States)

Brayda, L.; De Carli, F.; Chellali, R.; Famà, F.; Bruzzo, C.; Lucagrossi, L.; Rodriguez, G.

2012-01-01

The neural correlates of exploration and cognitive mapping in blindness remain elusive. The role of visuo-spatial pathways in blind vs. sighted subjects is still under debate. In this preliminary study, we investigate, as a possible estimation of the activity in the visuo-spatial pathways, the EEG patterns of blind and blindfolded-sighted subjects during the active tactile construction of cognitive maps from virtual objects compared with rest and passive tactile stimulation. Ten blind and ten matched, blindfolded-sighted subjects participated in the study. Events were defined as moments when the finger was only stimulated (passive stimulation) or the contour of a virtual object was touched (during active exploration). Event-related spectral power and coherence perturbations were evaluated within the beta 1 band (14–18 Hz). They were then related to a subjective cognitive-load estimation required by the explorations [namely, perceived levels of difficulty (PLD)]. We found complementary cues for sensory substitution and spatial processing in both groups: both blind and sighted subjects showed, while exploring, late power decreases and early power increases, potentially associated with motor programming and touch, respectively. The latter involved occipital areas only for blind subjects (long-term plasticity) and only during active exploration, thus supporting tactile-to-visual sensory substitution. In both groups, coherences emerged among the fronto-central, centro-parietal, and occipito-temporal derivations associated with visuo-spatial processing. This seems in accordance with mental map construction involving spatial processing, sensory-motor processing, and working memory. The observed involvement of the occipital regions suggests that a substitution process also occurs in sighted subjects. Only during explorations did coherence correlate positively with PLD for both groups and in derivations, which can be related to visuo-spatial processing, supporting the

An Adaptation-Induced Repulsion Illusion in Tactile Spatial Perception

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Lux Li

2017-06-01

Full Text Available 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.

Beats, Flesh, and Grain : Sonic Tactility and Affect in Electronic Dance Music

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Garcia, Luis-Manuel

2015-01-01

This essay sets out to explore the tactilization of sound in electronic dance music (EDM), which offers an important sensory-affective bridge between touch, sonic experience, and an expansive sense of connection in dancing crowds. EDM events tend to engender spaces of heightened tactility and

Tactile defensiveness and stereotyped behaviors.

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Baranek, G T; Foster, L G; Berkson, G

1997-02-01

This study explores the constructs of stereotyped behaviors (e.g., repetitive motor patterns, object manipulations, behavioral rigidities) and tactile defensiveness as relevant to occupational therapy theory and practice and attempts to test their purported relationships in children with developmental disabilities. Twenty-eight children with developmental disabilities and autism were assessed on eight factors of stereotyped behavior via a questionnaire and by four measures of tactile defensiveness. The subjects' scores from the questionnaire were correlated with their scores on the tactile defensiveness measures to see what, if any, relationship among these behaviors exists. Significant relationships emerged from the data, indicating that subjects with higher levels of tactile defensiveness were also more likely to evidence rigid or inflexible behaviors, repetitive verbalizations, visual stereotypes, and abnormal focused affections that are often associated with autism. No significant association was found between motor and object stereotypes and tactile defensiveness. These relationships could not be explained solely by maturational factors. The results suggest that clinicians should include observations of stereotyped behaviors, particularly behavioral rigidities, in conjunction with assessments of sensory defensiveness because these are related phenomena that may pose unique challenges for children with developmental disabilities and autism. Further study is needed to determine the causal mechanisms responsible for these relationships.

Bayesian Alternation During Tactile Augmentation

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Caspar Mathias Goeke

2016-10-01

Full Text Available A large number of studies suggest that the integration of multisensory signals by humans is well described by Bayesian principles. However, there are very few reports about cue combination between a native and an augmented sense. In particular, we asked the question whether adult participants are able to integrate an augmented sensory cue with existing native sensory information. Hence for the purpose of this study we build a tactile augmentation device. Consequently, we compared different hypotheses of how untrained adult participants combine information from a native and an augmented sense. In a two-interval forced choice (2 IFC task, while subjects were blindfolded and seated on a rotating platform, our sensory augmentation device translated information on whole body yaw rotation to tactile stimulation. Three conditions were realized: tactile stimulation only (augmented condition, rotation only (native condition, and both augmented and native information (bimodal condition. Participants had to choose one out of two consecutive rotations with higher angular rotation. For the analysis, we fitted the participants’ responses with a probit model and calculated the just notable difference (JND. Then we compared several models for predicting bimodal from unimodal responses. An objective Bayesian alternation model yielded a better prediction (χred2 = 1.67 than the Bayesian integration model (χred2= 4.34. Slightly higher accuracy showed a non-Bayesian winner takes all model (χred2= 1.64, which either used only native or only augmented values per subject for prediction. However the performance of the Bayesian alternation model could be substantially improved (χred2= 1.09 utilizing subjective weights obtained by a questionnaire. As a result, the subjective Bayesian alternation model predicted bimodal performance most accurately among all tested models. These results suggest that information from augmented and existing sensory modalities in

Tactile Working Memory Outside our Hands

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Takako Yoshida

2011-10-01

Full Text Available The haptic perception of 2D images is believed to make heavy demands on working memory. During active exploration, we need to store not only the current sensory information, but also to integrate this with kinesthetic information of the hand and fingers in order to generate a coherent percept. The question that arises is how much tactile memory we have for tactile stimuli that are no longer in contact with the skin during active touch? We examined working memory using a tactile change detection task with active exploration. Each trial contained two stimulation arrays. Participants engaged in unconstrained active tactile exploration of an array of vibrotactile stimulators. In half of the trials, one of the vibrating tactors that was active in the first stimulation turned off and another started vibrating in the second stimulation. Participants had to report whether the arrays were the same or different. Performance was near-perfect when up to two tactors were used and dropped linearly as the number of the vibrating tactors increased. These results suggest that the tactile working memory off the hand is limited and there is little or no memory integration across hand movements.

Anticipation increases tactile stimulus processing in the ipsilateral primary somatosensory cortex.

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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.

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

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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.

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Elena Nava

Full Text Available 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.

Restoring tactile awareness through the rubber hand illusion in cervical spinal cord injury.

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Lenggenhager, Bigna; Scivoletto, Giorgio; Molinari, Marco; Pazzaglia, Mariella

2013-10-01

Bodily sensations are an important component of corporeal awareness. Spinal cord injury can leave affected body parts insentient and unmoving, leading to specific disturbances in the mental representation of one's own body and the sense of self. Here, we explored how illusions induced by multisensory stimulation influence immediate sensory signals and tactile awareness in patients with spinal cord injuries. The rubber hand illusion paradigm was applied to 2 patients with chronic and complete spinal cord injury of the sixth cervical spine, with severe somatosensory impairments in 2 of 5 fingers. Both patients experienced a strong illusion of ownership of the rubber hand during synchronous, but not asynchronous, stroking. They also, spontaneously reported basic tactile sensations in their previously numb fingers. Tactile awareness from seeing the rubber hand was enhanced by progressively increasing the stimulation duration. Multisensory illusions directly and specifically modulate the reemergence of sensory memories and enhance tactile sensation, despite (or as a result of) prior deafferentation. When sensory inputs are lost, and are later illusorily regained, the brain updates a coherent body image even several years after the body has become permanently unable to feel. This particular example of neural plasticity represents a significant opportunity to strengthen the sense of the self and the feelings of embodiment in patients with spinal cord injury.

Analysis of sensory processing in preterm infants.

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Cabral, Thais Invenção; da Silva, Louise Gracelli Pereira; Martinez, Cláudia Maria Simões; Tudella, Eloisa

2016-12-01

Premature birth suggests condition of biological vulnerability, predisposing to neurological injuries, requiring hospitalization in Neonatal Intensive Care Units, which, while contributing to increase the survival rates, expose infants to sensory stimuli harmful to the immature organism. To evaluate the sensory processing at 4 and 6months' corrected age. This was a descriptive cross-sectional study with a sample of 30 infants divided into an experimental group composed of preterm infants (n=15), and a control group composed of full-term infants (n=15). The infants were assessed using the Test of Sensory Functions in Infants. The preterm infants showed poor performance in the total score of the test in reactivity to tactile deep pressure and reactivity to vestibular stimulation. When groups were compared, significant differences in the total score (p=0.0113) and in the reactivity to tactile deep pressure (psensory processing. These changes were most evident in reactivity to tactile deep pressure and vestibular stimulation. Copyright © 2016. Published by Elsevier Ireland Ltd.

Tactile feedback improves auditory spatial localization

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Monica eGori

2014-10-01

Full Text Available Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial-bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014. To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile-feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject’s forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal-feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no-feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially coherent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

Sensory prediction on a whiskered robot: A tactile analogy to "optic flow"

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Christopher L Schroeder

2012-10-01

Full Text Available When an animal moves an array of sensors (e.g., the hand, the eye through the environment, spatial and temporal gradients of sensory data are related by the velocity of the moving sensory array. In vision, the relationship between spatial and temporal brightness gradients is quantified in the optical flow equation. In the present work, we suggest an analog to optical flow for the rodent vibrissal (whisker array, in which the perceptual intensity that flows over the array is bending moment. Changes in bending moment are directly related to radial object distance, defined as the distance between the base of a whisker and the point of contact with the object. Using both simulations and a 1x5 array (row of artificial whiskers, we demonstrate that local object curvature can be estimated based on differences in radial distance across the array. We then develop two algorithms, both based on tactile flow, to predict the future contact points that will be obtained as the whisker array translates along the object. The translation of the robotic whisker array represents the rat's head velocity. The first algorithm uses a calculation of the local object slope, while the second uses a calculation of the local object curvature. Both algorithms successfully predict future contact points for simple surfaces. The algorithm based on curvature was found to more accurately predict future contact points as surfaces became more irregular. We quantify the inter-related effects of whisker spacing and the object’s spatial frequencies, and examine the issues that arise in the presence of real-world noise, friction, and slip.

Autism spectrum disorder in the scope of tactile processing

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Mark Mikkelsen

2018-01-01

Full Text Available Sensory processing abnormalities are among the most common behavioral phenotypes seen in autism spectrum disorder (ASD, typically characterized by either over- or under-responsiveness to stimulation. In this review, we focus on tactile processing dysfunction in ASD. We firstly review clinical studies wherein sensitivity to tactile stimuli has traditionally been assessed by self-, parent- and experimenter-reports. We also discuss recent investigations using psychophysical paradigms that gauge individual tactile thresholds. These more experimentally rigorous studies allow for more objective assessments of tactile abnormalities in ASD. However, little is understood about the neurobiological mechanisms underlying these abnormalities, or the link between tactile abnormalities and ASD symptoms. Neurobiological research that has been conducted has pointed toward dysfunction in the excitation/inhibition balance of the central nervous system of those with ASD. This review covers recent efforts that have investigated tactile dysfunction in ASD from clinical and behavioral perspectives, and some of the efforts to link these to neurobiology. On the whole, findings are inconsistent, which can be ascribed to the subjectivity of clinical assessments, the heterogeneity of ASD cohorts, and the diversity of tactile sensitivity measures. Future endeavors into understanding tactile processing differences in ASD will greatly benefit from controlled experiments driven by neurobiological hypotheses. Keywords: Autism spectrum disorder, Psychophysics, Review, Touch, Somatosensory, Tactile processing

Tactile acuity is disrupted in osteoarthritis but is unrelated to disruptions in motor imagery performance.

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Stanton, T.R.; Lin, C.W.; Bray, H.; Smeets, R.J.P.; Taylor, D.; Law, R.Y.; Moseley, G.L.

2013-01-01

OBJECTIVE: To determine whether tactile acuity is disrupted in people with knee OA and to determine whether tactile acuity, a clinical signature of primary sensory cortex representation, is related to motor imagery performance (MIP; evaluates working body schema) and pain. METHODS: Experiment 1:

Merkel cells transduce and encode tactile stimuli to drive Aβ-afferent impulses

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Ikeda, Ryo; Cha, Myeounghoon; Ling, Jennifer; Jia, Zhanfeng; Coyle, Dennis; Gu, Jianguo G.

2014-01-01

SUMMARY Sensory systems for detecting tactile stimuli have evolved from touch-sensing nerves in invertebrates to complicated tactile end-organs in mammals. Merkel discs are tactile end-organs consisting of Merkel cells and Aβ-afferent nerve endings, and are localized in fingertips, whisker hair follicles and other touch-sensitive spots. Merkel discs transduce touch into slowly adapting impulses to enable tactile discrimination, but their transduction and encoding mechanisms remain unknown. Using rat whisker hair follicles, we show that Merkel cells rather than Aβ-afferent nerve endings are primary sites of tactile transduction, and identify the Piezo2 ion channel as the Merkel cell mechanical transducer. Piezo2 transduces tactile stimuli into Ca2+-action potentials in Merkel cells, which drive Aβ-afferent nerve endings to fire slowly adapting impulses. We further demonstrate that Piezo2 and Ca2+-action potentials in Merkel cells are required for behavioral tactile responses. Our findings provide insights into how tactile end-organs function and have clinical implications for tactile dysfunctions. PMID:24746027

Correlations between motor and sensory functions in upper limb chronic hemiparetics after stroke

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Thais Botossi Scalha

2011-08-01

Full Text Available OBJECTIVE: Describe the somatosensory function of the affected upper limb of hemiparetic stroke patients and investigate the correlations between measurements of motor and sensory functions in tasks with and without visual deprivation. METHOD: We applied the Fugl-Meyer Assessment (FMA, Nottingham Sensory Assessment (NSA, and several motor and sensory tests: Paper manipulation (PM, Motor Sequences (MS, Reaching and grasping (RG Tests Functional (TF, Tactile Discrimination (TD, Weight Discrimination (WD and Tactile Recognition of Objects (RO. RESULTS: We found moderate correlations between the FMA motor subscale and the tactile sensation score of the NSA. Additionally, the FMA sensitivity was correlated with the NSA total; and performance on the WD test items correlated with the NSA. CONCLUSION: There was a correlation between the sensory and motor functions of the upper limb in chronic hemiparetic stroke patients. Additionally, there was a greater reliance on visual information to compensate for lost sensory-motor skills.

Left hand tactile agnosia after posterior callosal lesion.

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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.

Tactile Gap Detection Deteriorates during Bimanual Symmetrical Movements under Mirror Visual Feedback.

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Janet H Bultitude

Full Text Available It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual

Action preparation modulates sensory perception in unseen personal space: An electrophysiological investigation.

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Job, Xavier E; de Fockert, Jan W; van Velzen, José

2016-08-01

Behavioural and electrophysiological evidence has demonstrated that preparation of goal-directed actions modulates sensory perception at the goal location before the action is executed. However, previous studies have focused on sensory perception in areas of peripersonal space. The present study investigated visual and tactile sensory processing at the goal location of upcoming movements towards the body, much of which is not visible, as well as visible peripersonal space. A motor task cued participants to prepare a reaching movement towards goals either in peripersonal space in front of them or personal space on the upper chest. In order to assess modulations of sensory perception during movement preparation, event-related potentials (ERPs) were recorded in response to task-irrelevant visual and tactile probe stimuli delivered randomly at one of the goal locations of the movements. In line with previous neurophysiological findings, movement preparation modulated visual processing at the goal of a movement in peripersonal space. Movement preparation also modulated somatosensory processing at the movement goal in personal space. The findings demonstrate that tactile perception in personal space is subject to similar top-down sensory modulation by motor preparation as observed for visual stimuli presented in peripersonal space. These findings show for the first time that the principles and mechanisms underlying adaptive modulation of sensory processing in the context of action extend to tactile perception in unseen personal space. Copyright © 2016 Elsevier Ltd. All rights reserved.

touché is required for touch evoked generator potentials within vertebrate sensory neurons

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Low, Sean E.; Ryan, Joel; Sprague, Shawn M.; Hirata, Hiromi; Cui, Wilson W.; Zhou, Weibin; Hume, Richard I.; Kuwada, John Y.; Saint-Amant, Louis

2010-01-01

The process by which light-touch in vertebrates is transformed into an electrical response in cutaneous mechanosensitive neurons is a largely unresolved question. To address this question we undertook a forward genetic screen in zebrafish (Danio rerio) to identify mutants exhibiting abnormal touch-evoked behaviors, despite the presence of sensory neurons and peripheral neurites. One family, subsequently named touché, was found to harbor a recessive mutation which produced offspring that were unresponsive to light-touch, but responded to a variety of other sensory stimuli. The optogenetic activation of motor behaviors by touché mutant sensory neurons expressing ChannelRhodopsin-2 suggested that the synaptic output of sensory neurons was intact, consistent with a defect in sensory neuron activation. To explore sensory neuron activation we developed an in vivo preparation permitting the precise placement of a combined electrical and tactile stimulating probe upon eGFP positive peripheral neurites. In wild type larva electrical and tactile stimulation of peripheral neurites produced action potentials detectable within the cell body. In a subset of these sensory neurons an underlying generator potential could be observed in response to subthreshold tactile stimuli. A closer examination revealed that the amplitude of the generator potential was proportional to the stimulus amplitude. When assayed touché mutant sensory neurons also responded to electrical stimulation of peripheral neurites similar to wild type larvae, however tactile stimulation of these neurites failed to uncover a subset of sensory neurons possessing generator potentials. These findings suggest that touché is required for generator potentials, and that generator potentials underlie responsiveness to light-touch in zebrafish. PMID:20631165

Short-term visual deprivation does not enhance passive tactile spatial acuity.

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Michael Wong

Full Text Available An important unresolved question in sensory neuroscience is whether, and if so with what time course, tactile perception is enhanced by visual deprivation. In three experiments involving 158 normally sighted human participants, we assessed whether tactile spatial acuity improves with short-term visual deprivation over periods ranging from under 10 to over 110 minutes. We used an automated, precisely controlled two-interval forced-choice grating orientation task to assess each participant's ability to discern the orientation of square-wave gratings pressed against the stationary index finger pad of the dominant hand. A two-down one-up staircase (Experiment 1 or a Bayesian adaptive procedure (Experiments 2 and 3 was used to determine the groove width of the grating whose orientation each participant could reliably discriminate. The experiments consistently showed that tactile grating orientation discrimination does not improve with short-term visual deprivation. In fact, we found that tactile performance degraded slightly but significantly upon a brief period of visual deprivation (Experiment 1 and did not improve over periods of up to 110 minutes of deprivation (Experiments 2 and 3. The results additionally showed that grating orientation discrimination tends to improve upon repeated testing, and confirmed that women significantly outperform men on the grating orientation task. We conclude that, contrary to two recent reports but consistent with an earlier literature, passive tactile spatial acuity is not enhanced by short-term visual deprivation. Our findings have important theoretical and practical implications. On the theoretical side, the findings set limits on the time course over which neural mechanisms such as crossmodal plasticity may operate to drive sensory changes; on the practical side, the findings suggest that researchers who compare tactile acuity of blind and sighted participants should not blindfold the sighted participants.

Variation in the autism candidate gene GABRB3 modulates tactile sensitivity in typically developing children

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Tavassoli Teresa

2012-07-01

Full Text Available Abstract Background Autism spectrum conditions have a strong genetic component. Atypical sensory sensitivities are one of the core but neglected features of autism spectrum conditions. GABRB3 is a well-characterised candidate gene for autism spectrum conditions. In mice, heterozygous Gabrb3 deletion is associated with increased tactile sensitivity. However, no study has examined if tactile sensitivity is associated with GABRB3 genetic variation in humans. To test this, we conducted two pilot genetic association studies in the general population, analysing two phenotypic measures of tactile sensitivity (a parent-report and a behavioural measure for association with 43 SNPs in GABRB3. Findings Across both tactile sensitivity measures, three SNPs (rs11636966, rs8023959 and rs2162241 were nominally associated with both phenotypes, providing a measure of internal validation. Parent-report scores were nominally associated with six SNPs (P Conclusions This is the first human study to show an association between GABRB3 variation and tactile sensitivity. This provides support for the evidence from animal models implicating the role of GABRB3 variation in the atypical sensory sensitivity in autism spectrum conditions. Future research is underway to directly test this association in cases of autism spectrum conditions.

Relative contributions of visual and auditory spatial representations to tactile localization.

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Noel, Jean-Paul; Wallace, Mark

2016-02-01

Spatial localization of touch is critically dependent upon coordinate transformation between different reference frames, which must ultimately allow for alignment between somatotopic and external representations of space. Although prior work has shown an important role for cues such as body posture in influencing the spatial localization of touch, the relative contributions of the different sensory systems to this process are unknown. In the current study, we had participants perform a tactile temporal order judgment (TOJ) under different body postures and conditions of sensory deprivation. Specifically, participants performed non-speeded judgments about the order of two tactile stimuli presented in rapid succession on their ankles during conditions in which their legs were either uncrossed or crossed (and thus bringing somatotopic and external reference frames into conflict). These judgments were made in the absence of 1) visual, 2) auditory, or 3) combined audio-visual spatial information by blindfolding and/or placing participants in an anechoic chamber. As expected, results revealed that tactile temporal acuity was poorer under crossed than uncrossed leg postures. Intriguingly, results also revealed that auditory and audio-visual deprivation exacerbated the difference in tactile temporal acuity between uncrossed to crossed leg postures, an effect not seen for visual-only deprivation. Furthermore, the effects under combined audio-visual deprivation were greater than those seen for auditory deprivation. Collectively, these results indicate that mechanisms governing the alignment between somatotopic and external reference frames extend beyond those imposed by body posture to include spatial features conveyed by the auditory and visual modalities - with a heavier weighting of auditory than visual spatial information. Thus, sensory modalities conveying exteroceptive spatial information contribute to judgments regarding the localization of touch. Copyright © 2016

Electrophysiological Evidence for a Sensory Recruitment Model of Somatosensory Working Memory.

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Katus, Tobias; Grubert, Anna; Eimer, Martin

2015-12-01

Sensory recruitment models of working memory assume that information storage is mediated by the same cortical areas that are responsible for the perceptual processing of sensory signals. To test this assumption, we measured somatosensory event-related brain potentials (ERPs) during a tactile delayed match-to-sample task. Participants memorized a tactile sample set at one task-relevant hand to compare it with a subsequent test set on the same hand. During the retention period, a sustained negativity (tactile contralateral delay activity, tCDA) was elicited over primary somatosensory cortex contralateral to the relevant hand. The amplitude of this component increased with memory load and was sensitive to individual limitations in memory capacity, suggesting that the tCDA reflects the maintenance of tactile information in somatosensory working memory. The tCDA was preceded by a transient negativity (N2cc component) with a similar contralateral scalp distribution, which is likely to reflect selection of task-relevant tactile stimuli at the encoding stage. The temporal sequence of N2cc and tCDA components mirrors previous observations from ERP studies of working memory in vision. The finding that the sustained somatosensory delay period activity varies as a function of memory load supports a sensory recruitment model for spatial working memory in touch. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Perceived duration of visual and tactile stimuli depends on perceived speed

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Alice eTomassini

2011-09-01

Full Text Available It is known that the perceived duration of visual stimuli is strongly influenced by speed: faster moving stimuli appear to last longer. To test whether this is a general property of sensory systems we asked participants to reproduce the duration of visual and tactile gratings, and visuo-tactile gratings moving at a variable speed (3.5 – 15 cm/s for three different durations (400, 600 and 800 ms. For both modalities, the apparent duration of the stimulus increased strongly with stimulus speed, more so for tactile than for visual stimuli. In addition, visual stimuli were perceived to last approximately 200 ms longer than tactile stimuli. The apparent duration of visuo-tactile stimuli lay between the unimodal estimates, as the Bayesian account predicts, but the bimodal precision of the reproduction did not show the theoretical improvement. A cross-modal speed-matching task revealed that visual stimuli were perceived to move faster than tactile stimuli. To test whether the large difference in the perceived duration of visual and tactile stimuli resulted from the difference in their perceived speed, we repeated the time reproduction task with visual and tactile stimuli matched in apparent speed. This reduced, but did not completely eliminate the difference in apparent duration. These results show that for both vision and touch, perceived duration depends on speed, pointing to common strategies of time perception.

Spatial auditory attention is modulated by tactile priming.

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Menning, Hans; Ackermann, Hermann; Hertrich, Ingo; Mathiak, Klaus

2005-07-01

Previous studies have shown that cross-modal processing affects perception at a variety of neuronal levels. In this study, event-related brain responses were recorded via whole-head magnetoencephalography (MEG). Spatial auditory attention was directed via tactile pre-cues (primes) to one of four locations in the peripersonal space (left and right hand versus face). Auditory stimuli were white noise bursts, convoluted with head-related transfer functions, which ensured spatial perception of the four locations. Tactile primes (200-300 ms prior to acoustic onset) were applied randomly to one of these locations. Attentional load was controlled by three different visual distraction tasks. The auditory P50m (about 50 ms after stimulus onset) showed a significant "proximity" effect (larger responses to face stimulation as well as a "contralaterality" effect between side of stimulation and hemisphere). The tactile primes essentially reduced both the P50m and N100m components. However, facial tactile pre-stimulation yielded an enhanced ipsilateral N100m. These results show that earlier responses are mainly governed by exogenous stimulus properties whereas cross-sensory interaction is spatially selective at a later (endogenous) processing stage.

High-Frequency Repetitive Sensory Stimulation as Intervention to Improve Sensory Loss in Patients with Complex Regional Pain Syndrome I.

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David, Marianne; Dinse, Hubert R; Mainka, Tina; Tegenthoff, Martin; Maier, Christoph

2015-01-01

Achieving perceptual gains in healthy individuals or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS). For example, high-frequency repetitive sensory stimulation (HF-rSS) enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS) show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS) to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high- or low-frequency electrical stimuli were applied for 45 min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial two-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in four patients by ≥30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all four patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.

Force control in the absence of visual and tactile feedback

NARCIS (Netherlands)

Mugge, W.; Abbink, D.A.; Schouten, Alfred Christiaan; van der Helm, F.C.T.; Arendzen, J.H.; Meskers, C.G.M.

2013-01-01

Motor control tasks like stance or object handling require sensory feedback from proprioception, vision and touch. The distinction between tactile and proprioceptive sensors is not frequently made in dynamic motor control tasks, and if so, mostly based on signal latency. We previously found that

An Extreme Learning Machine-Based Neuromorphic Tactile Sensing System for Texture Recognition.

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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

Synthetic and Bio-Artificial Tactile Sensing: A Review

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Maria Chiara Carrozza

2013-01-01

Full Text Available 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.

Implications of Sensory Stimulation in Self-Destructive Behavior.

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Edelson, Stephen M.

1984-01-01

The author extends the self stimulatory theory of self destructive behavior in autistic, schizophrenic, and mentally retarded individuals to suggest that damage of the skin's nerve structure lowers the tactile sensory threshold for physical input and enables individuals to obtain sensory stimulation by repeatedly depressing the damaged area. (CL)

Tactility and the body in early Chinese medicine.

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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.

High frequency repetitive sensory stimulation as intervention to improve sensory loss in patients with complex regional pain syndrome (CRPS I

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Marianne eDavid

2015-11-01

Full Text Available Achieving perceptual gains in healthy individuals, or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS. For example, high-frequency repetitive sensory stimulation (HF-rSS enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high or low frequency electrical stimuli were applied for 45min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial 2-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in 4 patients by 30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all 4 patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.

Tactile acuity and lumbopelvic motor control in patients with back pain and healthy controls.

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Luomajoki, H; Moseley, G L

2011-04-01

Voluntary lumbopelvic control is compromised in patients with back pain. Loss of proprioceptive acuity is one contributor to decreased control. Several reasons for decreased proprioceptive acuity have been proposed, but the integrity of cortical body maps has been overlooked. We investigated whether tactile acuity, a clear clinical signature of primary sensory cortex organisation, relates to lumbopelvic control in people with back pain. Forty-five patients with back pain and 45 age- and sex-matched healthy controls participated in this cross-sectional study. Tactile acuity at the back was assessed using two-point discrimination (TPD) threshold in vertical and horizontal directions. Voluntary motor control was assessed using an established battery of clinical tests. Patients performed worse on the voluntary lumbopelvic tasks than healthy controls did (p<0.001). TPD threshold was larger in patients (mean (SD)=61 (13) mm) than in healthy controls (44 (10) mm). Moreover, larger TPD threshold was positively related to worse performance on the voluntary lumbopelvic tasks (Pearson's r=0.49; p<0.001). Tactile acuity, a clear clinical signature of primary sensory cortex organisation, relates to voluntary lumbopelvic control. This relationship raises the possibility that the former contributes to the latter, in which case training tactile acuity may aid recovery and assist in achieving normal motor performance after back injury.

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

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Di Feng

2018-02-01

Full Text Available 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.

The Effect of Tactile Cues on Auditory Stream Segregation Ability of Musicians and Nonmusicians

DEFF Research Database (Denmark)

Slater, Kyle D.; Marozeau, Jeremy

2016-01-01

Difficulty perceiving music is often cited as one of the main problems facing hearing-impaired listeners. It has been suggested that musical enjoyment could be enhanced if sound information absent due to impairment is transmitted via other sensory modalities such as vision or touch. In this study...... the random melody. Tactile cues were applied to the listener’s fingers on half of the blocks. Results showed that tactile cues can significantly improve the melodic segregation ability in both musician and nonmusician groups in challenging listening conditions. Overall, the musician group performance...... was always better; however, the magnitude of improvement with the introduction of tactile cues was similar in both groups. This study suggests that hearing-impaired listeners could potentially benefit from a system transmitting such information via a tactile modality...

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

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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

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

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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.

Tactile search for change has less memory than visual search for change.

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Yoshida, Takako; Yamaguchi, Ayumi; Tsutsui, Hideomi; Wake, Tenji

2015-05-01

Haptic perception of a 2D image is thought to make heavy demands on working memory. During active exploration, humans need to store the latest local sensory information and integrate it with kinesthetic information from hand and finger locations in order to generate a coherent perception. This tactile integration has not been studied as extensively as visual shape integration. In the current study, we compared working-memory capacity for tactile exploration to that of visual exploration as measured in change-detection tasks. We found smaller memory capacity during tactile exploration (approximately 1 item) compared with visual exploration (2-10 items). These differences generalized to position memory and could not be attributed to insufficient stimulus-exposure durations, acuity differences between modalities, or uncertainty over the position of items. This low capacity for tactile memory suggests that the haptic system is almost amnesic when outside the fingertips and that there is little or no cross-position integration.

Differences in two-point discrimination and sensory threshold in the blind between braille and text reading: a pilot study.

Science.gov (United States)

Noh, Ji-Woong; Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kang, Ji-Hye; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-06-01

[Purpose] This study investigated two-point discrimination (TPD) and the electrical sensory threshold of the blind to define the effect of using Braille on the tactile and electrical senses. [Subjects and Methods] Twenty-eight blind participants were divided equally into a text-reading and a Braille-reading group. We measured tactile sensory and electrical thresholds using the TPD method and a transcutaneous electrical nerve stimulator. [Results] The left palm TPD values were significantly different between the groups. The values of the electrical sensory threshold in the left hand, the electrical pain threshold in the left hand, and the electrical pain threshold in the right hand were significantly lower in the Braille group than in the text group. [Conclusion] These findings make it difficult to explain the difference in tactility between groups, excluding both palms. However, our data show that using Braille can enhance development of the sensory median nerve in the blind, particularly in terms of the electrical sensory and pain thresholds.

A Review of Smart Materials in Tactile Actuators for Information Delivery

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Xin Xie

2017-12-01

Full Text Available As the largest organ in the human body, the skin provides the important sensory channel for humans to receive external stimulations based on touch. By the information perceived through touch, people can feel and guess the properties of objects, like weight, temperature, textures, and motion, etc. In fact, those properties are nerve stimuli to our brain received by different kinds of receptors in the skin. Mechanical, electrical, and thermal stimuli can stimulate these receptors and cause different information to be conveyed through the nerves. Technologies for actuators to provide mechanical, electrical or thermal stimuli have been developed. These include static or vibrational actuation, electrostatic stimulation, focused ultrasound, and more. Smart materials, such as piezoelectric materials, carbon nanotubes, and shape memory alloys, play important roles in providing actuation for tactile sensation. This paper aims to review the background biological knowledge of human tactile sensing, to give an understanding of how we sense and interact with the world through the sense of touch, as well as the conventional and state-of-the-art technologies of tactile actuators for tactile feedback delivery.

Endoscopic vs. tactile evaluation of subgingival calculus.

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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 (pcalculus detection from baseline to visit 1 were statistically significant for both the Perioscope™ and tactile quadrants (pcalculus detection from visit 1 to visit 2 was only significant for the Perioscope™ quadrant (pcalculus 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.

Effectiveness of auditory and tactile crossmodal cues in a dual-task visual and auditory scenario.

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Hopkins, Kevin; Kass, Steven J; Blalock, Lisa Durrance; Brill, J Christopher

2017-05-01

In this study, we examined how spatially informative auditory and tactile cues affected participants' performance on a visual search task while they simultaneously performed a secondary auditory task. Visual search task performance was assessed via reaction time and accuracy. Tactile and auditory cues provided the approximate location of the visual target within the search display. The inclusion of tactile and auditory cues improved performance in comparison to the no-cue baseline conditions. In comparison to the no-cue conditions, both tactile and auditory cues resulted in faster response times in the visual search only (single task) and visual-auditory (dual-task) conditions. However, the effectiveness of auditory and tactile cueing for visual task accuracy was shown to be dependent on task-type condition. Crossmodal cueing remains a viable strategy for improving task performance without increasing attentional load within a singular sensory modality. Practitioner Summary: Crossmodal cueing with dual-task performance has not been widely explored, yet has practical applications. We examined the effects of auditory and tactile crossmodal cues on visual search performance, with and without a secondary auditory task. Tactile cues aided visual search accuracy when also engaged in a secondary auditory task, whereas auditory cues did not.

Purposeful Goal-Directed Movements Give Rise to Higher Tactile Discrimination Performance

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Georgiana Juravle

2011-10-01

Full Text Available Tactile perception is inhibited during goal-directed reaching movements (sensory suppression. Here, participants performed simple reaching or exploratory movements (where contact with the table surface was maintained. We measured tactile discrimination thresholds for vibratory stimuli delivered to participants' wrists while executing the movement, and while at rest. Moreover, we measured discrimination performance (in a same vs. different task for the materials covering the table surface, during the execution of the different movements. The threshold and discrimination tasks could be performed either singly or together, both under active movement and passive conditions (ie, no movement required, but with tactile stimulation. Thresholds measured at rest were significantly lower than thresholds measured during both active movements and passive touches. This provides a clear indication of sensory suppression during movement execution. Moreover, the discrimination data revealed main effects of task (single vs. dual, movement execution type (passive vs. active, and movement type (reach vs. exploration: Discrimination performance was significantly higher under conditions of single-tasking, active movements, as well as exploratory movements. Therefore, active movement of the hand with the purpose of gaining tactual information about the surface of the table gives rise to enhanced performance, thus suggesting that we feel more when we need to; It would appear that tactual information is prioritized when relevant for the movement being executed.

Behavioral Impact of Unisensory and Multisensory Audio-Tactile Events: Pros and Cons for Interlimb Coordination in Juggling

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Zelic, Gregory; Mottet, Denis; Lagarde, Julien

2012-01-01

Recent behavioral neuroscience research revealed that elementary reactive behavior can be improved in the case of cross-modal sensory interactions thanks to underlying multisensory integration mechanisms. Can this benefit be generalized to an ongoing coordination of movements under severe physical constraints? We choose a juggling task to examine this question. A central issue well-known in juggling lies in establishing and maintaining a specific temporal coordination among balls, hands, eyes and posture. Here, we tested whether providing additional timing information about the balls and hands motions by using external sound and tactile periodic stimulations, the later presented at the wrists, improved the behavior of jugglers. One specific combination of auditory and tactile metronome led to a decrease of the spatiotemporal variability of the juggler's performance: a simple sound associated to left and right tactile cues presented antiphase to each other, which corresponded to the temporal pattern of hands movement in the juggling task. A contrario, no improvements were obtained in the case of other auditory and tactile combinations. We even found a degraded performance when tactile events were presented alone. The nervous system thus appears able to integrate in efficient way environmental information brought by different sensory modalities, but only if the information specified matches specific features of the coordination pattern. We discuss the possible implications of these results for the understanding of the neuronal integration process implied in audio-tactile interaction in the context of complex voluntary movement, and considering the well-known gating effect of movement on vibrotactile perception. PMID:22384211

Behavioral impact of unisensory and multisensory audio-tactile events: pros and cons for interlimb coordination in juggling.

Directory of Open Access Journals (Sweden)

Gregory Zelic

Full Text Available Recent behavioral neuroscience research revealed that elementary reactive behavior can be improved in the case of cross-modal sensory interactions thanks to underlying multisensory integration mechanisms. Can this benefit be generalized to an ongoing coordination of movements under severe physical constraints? We choose a juggling task to examine this question. A central issue well-known in juggling lies in establishing and maintaining a specific temporal coordination among balls, hands, eyes and posture. Here, we tested whether providing additional timing information about the balls and hands motions by using external sound and tactile periodic stimulations, the later presented at the wrists, improved the behavior of jugglers. One specific combination of auditory and tactile metronome led to a decrease of the spatiotemporal variability of the juggler's performance: a simple sound associated to left and right tactile cues presented antiphase to each other, which corresponded to the temporal pattern of hands movement in the juggling task. A contrario, no improvements were obtained in the case of other auditory and tactile combinations. We even found a degraded performance when tactile events were presented alone. The nervous system thus appears able to integrate in efficient way environmental information brought by different sensory modalities, but only if the information specified matches specific features of the coordination pattern. We discuss the possible implications of these results for the understanding of the neuronal integration process implied in audio-tactile interaction in the context of complex voluntary movement, and considering the well-known gating effect of movement on vibrotactile perception.

A Feeling for Numbers: Shared Metric for Symbolic and Tactile Numerosities

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Florian eKrause

2013-01-01

Full Text Available Evidence for an approximate analogue system of numbers has been provided by the finding that the comparison of two numerals takes longer and is more error prone if the semantic distance between the numbers becomes smaller (so-called numerical distance effect. Recent embodied theories suggest that analogue number representations are based on previous sensory experiences and constitute therefore a common magnitude metric shared by multiple domains. Here we demonstrate the existence of a cross-modal semantic distance effect between symbolic and tactile numerosities. Participants received tactile stimulations of different amounts of fingers while reading Arabic digits and indicated verbally whether the amount of stimulated fingers was different from the simultaneously presented digit or not. The larger the semantic distance was between the two numerosities, the faster and more accurate participants made their judgements. This cross-modal numerosity distance effect suggests a direct connection between tactile sensations and the concept of numerical magnitude. A second experiment replicated the interaction between symbolic and tactile numerosities and showed that this effect is not modulated by the participants' finger counting habits. Taken together, our data provide novel evidence for a shared metric for symbolic and tactile numerosites as an instance of an embodied representation of numbers.

Agreeable smellers and sensitive neurotics--correlations among personality traits and sensory thresholds.

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Croy, Ilona; Springborn, Maria; Lötsch, Jörn; Johnston, Amy N B; Hummel, Thomas

2011-04-27

Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (N = 124) completed a personality inventory (NEO-FFI) and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality.

Preferential processing of tactile events under conditions of divided attention: Effects of divided attention on reaction time

OpenAIRE

Hanson, James V. M.; Whitaker, David; Heron, James

2009-01-01

Differences in transduction and transmission latencies of visual, auditory and tactile events cause corresponding differences in simple reaction time. As reaction time is usually measured in unimodal blocks, it is unclear whether such latency differences also apply when observers monitor multiple sensory channels. We investigate this by comparing reaction time when attention is focussed on a single modality, and when attention is divided between multiple modalities. Results show that tactile ...

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

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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…

Feeling music: integration of auditory and tactile inputs in musical meter perception.

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Huang, Juan; Gamble, Darik; Sarnlertsophon, Kristine; Wang, Xiaoqin; Hsiao, Steven

2012-01-01

Musicians often say that they not only hear, but also "feel" music. To explore the contribution of tactile information in "feeling" musical rhythm, we investigated the degree that auditory and tactile inputs are integrated in humans performing a musical meter recognition task. Subjects discriminated between two types of sequences, 'duple' (march-like rhythms) and 'triple' (waltz-like rhythms) presented in three conditions: 1) Unimodal inputs (auditory or tactile alone), 2) Various combinations of bimodal inputs, where sequences were distributed between the auditory and tactile channels such that a single channel did not produce coherent meter percepts, and 3) Simultaneously presented bimodal inputs where the two channels contained congruent or incongruent meter cues. We first show that meter is perceived similarly well (70%-85%) when tactile or auditory cues are presented alone. We next show in the bimodal experiments that auditory and tactile cues are integrated to produce coherent meter percepts. Performance is high (70%-90%) when all of the metrically important notes are assigned to one channel and is reduced to 60% when half of these notes are assigned to one channel. When the important notes are presented simultaneously to both channels, congruent cues enhance meter recognition (90%). Performance drops dramatically when subjects were presented with incongruent auditory cues (10%), as opposed to incongruent tactile cues (60%), demonstrating that auditory input dominates meter perception. We believe that these results are the first demonstration of cross-modal sensory grouping between any two senses.

Sensory Feedback for Lower Extremity Prostheses Incorporating Targeted Muscle Reinnervation (TMR)

Science.gov (United States)

2017-10-01

hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and...map and characterize the sensory capabilities of lower extremity Targeted Reinnervation (TR) sites under tactile stimulation , and (2) Measure the...descent machine; developed new tactile stimulators that we expect to use in later stages of this project; and completed baseline studies to calibrate

Audio-Tactile Integration and the Influence of Musical Training

OpenAIRE

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 function...

Independent Attention Mechanisms Control the Activation of Tactile and Visual Working Memory Representations.

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Katus, Tobias; Eimer, Martin

2018-05-01

Working memory (WM) is limited in capacity, but it is controversial whether these capacity limitations are domain-general or are generated independently within separate modality-specific memory systems. These alternative accounts were tested in bimodal visual/tactile WM tasks. In Experiment 1, participants memorized the locations of simultaneously presented task-relevant visual and tactile stimuli. Visual and tactile WM load was manipulated independently (one, two, or three items per modality), and one modality was unpredictably tested after each trial. To track the activation of visual and tactile WM representations during the retention interval, the visual contralateral delay activity (CDA) and tactile CDA (tCDA) were measured over visual and somatosensory cortex, respectively. CDA and tCDA amplitudes were selectively affected by WM load in the corresponding (tactile or visual) modality. The CDA parametrically increased when visual load increased from one to two and to three items. The tCDA was enhanced when tactile load increased from one to two items and showed no further enhancement for three tactile items. Critically, these load effects were strictly modality-specific, as substantiated by Bayesian statistics. Increasing tactile load did not affect the visual CDA, and increasing visual load did not modulate the tCDA. Task performance at memory test was also unaffected by WM load in the other (untested) modality. This was confirmed in a second behavioral experiment where tactile and visual loads were either two or four items, unimodal baseline conditions were included, and participants performed a color change detection task in the visual modality. These results show that WM capacity is not limited by a domain-general mechanism that operates across sensory modalities. They suggest instead that WM storage is mediated by distributed modality-specific control mechanisms that are activated independently and in parallel during multisensory WM.

Tactile display landing safety and precision improvements for the Space Shuttle

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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.

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

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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.

Agreeable smellers and sensitive neurotics--correlations among personality traits and sensory thresholds.

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Ilona Croy

Full Text Available Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (N = 124 completed a personality inventory (NEO-FFI and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality.

An MRI-compatible hand sensory vibrotactile system

International Nuclear Information System (INIS)

Wang, Fa; Lakshminarayanan, Kishor; Slota, Gregory P; Seo, Na Jin; Webster, John G

2015-01-01

Recently, the application of vibrotactile noise to the wrist or back of the hand has been shown to enhance fingertip tactile sensory perception (Enders et al 2013), supporting the potential for an assistive device worn at the wrist, that generates minute vibrations to help the elderly or patients with sensory deficit. However, knowledge regarding the detailed physiological mechanism behind this sensory improvement in the central nervous system, especially in the human brain, is limited, hindering progress in development and use of such assistive devices. To enable investigation of the impact of vibrotactile noise on sensorimotor brain activity in humans, a magnetic resonance imaging (MRI)-compatible vibrotactile system was developed to provide vibrotactile noise during an MRI of the brain. The vibrotactile system utilizes a remote (outside the MR room) signal amplifier which provides a voltage from –40 to +40 V to drive a 12 mm diameter piezoelectric vibrator (inside the MR room). It is portable and is found to be MRI-compatible which enables its use for neurologic investigation with MRI. The system was also found to induce an improvement in fingertip tactile sensation, consistent with the previous study. (note)

Psychophysical evaluation of a variable friction tactile interface

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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.

Altered Sensory Feedbacks in Pianist's Dystonia: the altered auditory feedback paradigm and the glove effect

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Felicia Pei-Hsin Cheng

2013-12-01

Full Text Available Background: This study investigates the effect of altered auditory feedback (AAF in musician's dystonia (MD and discusses whether altered auditory feedback can be considered as a sensory trick in MD. Furthermore, the effect of AAF is compared with altered tactile feedback, which can serve as a sensory trick in several other forms of focal dystonia. Methods: The method is based on scale analysis (Jabusch et al. 2004. Experiment 1 employs synchronization paradigm: 12 MD patients and 25 healthy pianists had to repeatedly play C-major scales in synchrony with a metronome on a MIDI-piano with 3 auditory feedback conditions: 1. normal feedback; 2. no feedback; 3. constant delayed feedback. Experiment 2 employs synchronization-continuation paradigm: 12 MD patients and 12 healthy pianists had to repeatedly play C-major scales in two phases: first in synchrony with a metronome, secondly continue the established tempo without the metronome. There are 4 experimental conditions, among them 3 are the same altered auditory feedback as in Experiment 1 and 1 is related to altered tactile sensory input. The coefficient of variation of inter-onset intervals of the key depressions was calculated to evaluate fine motor control. Results: In both experiments, the healthy controls and the patients behaved very similarly. There is no difference in the regularity of playing between the two groups under any condition, and neither did AAF nor did altered tactile feedback have a beneficial effect on patients’ fine motor control. Conclusions: The results of the two experiments suggest that in the context of our experimental designs, AAF and altered tactile feedback play a minor role in motor coordination in patients with musicians' dystonia. We propose that altered auditory and tactile feedback do not serve as effective sensory tricks and may not temporarily reduce the symptoms of patients suffering from MD in this experimental context.

A diagnostic model incorporating P50 sensory gating and neuropsychological tests for schizophrenia.

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Jia-Chi Shan

Full Text Available OBJECTIVES: Endophenotypes in schizophrenia research is a contemporary approach to studying this heterogeneous mental illness, and several candidate neurophysiological markers (e.g. P50 sensory gating and neuropsychological tests (e.g. Continuous Performance Test (CPT and Wisconsin Card Sorting Test (WCST have been proposed. However, the clinical utility of a single marker appears to be limited. In the present study, we aimed to construct a diagnostic model incorporating P50 sensory gating with other neuropsychological tests in order to improve the clinical utility. METHODS: We recruited clinically stable outpatients meeting DSM-IV criteria of schizophrenia and age- and gender-matched healthy controls. Participants underwent P50 sensory gating experimental sessions and batteries of neuropsychological tests, including CPT, WCST and Wechsler Adult Intelligence Scale Third Edition (WAIS-III. RESULTS: A total of 106 schizophrenia patients and 74 healthy controls were enrolled. Compared with healthy controls, the patient group had significantly a larger S2 amplitude, and thus poorer P50 gating ratio (gating ratio = S2/S1. In addition, schizophrenia patients had a poorer performance on neuropsychological tests. We then developed a diagnostic model by using multivariable logistic regression analysis to differentiate patients from healthy controls. The final model included the following covariates: abnormal P50 gating (defined as P50 gating ratio >0.4, three subscales derived from the WAIS-III (Arithmetic, Block Design, and Performance IQ, sensitivity index from CPT and smoking status. This model had an adequate accuracy (concordant percentage = 90.4%; c-statistic = 0.904; Hosmer-Lemeshow Goodness-of-Fit Test, p = 0.64>0.05. CONCLUSION: To the best of our knowledge, this is the largest study to date using P50 sensory gating in subjects of Chinese ethnicity and the first to use P50 sensory gating along with other neuropsychological tests

Agreeable Smellers and Sensitive Neurotics – Correlations among Personality Traits and Sensory Thresholds

Science.gov (United States)

Croy, Ilona; Springborn, Maria; Lötsch, Jörn; Johnston, Amy N. B.; Hummel, Thomas

2011-01-01

Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (N = 124) completed a personality inventory (NEO-FFI) and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality. PMID:21556139

Activation of sensory cortex by imagined genital stimulation: an fMRI analysis.

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Wise, Nan J; Frangos, Eleni; Komisaruk, Barry R

2016-01-01

During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. This study extends our previous findings by further characterizing how the brain differentially processes physical 'touch' stimulation and 'imagined' stimulation. Eleven healthy women (age range 29-74) participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions - imagined dildo self-stimulation and imagined speculum stimulation - were included to characterize the effects of erotic versus non-erotic imagery. Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex) and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region), and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the 'reward system'. In addition, these results suggest a mechanism by which some individuals may

Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

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Nan J. Wise

2016-10-01

Full Text Available Background: During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. Objective: This study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation. Design: Eleven healthy women (age range 29–74 participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery. Results: Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region, and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. Conclusion: The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the �

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

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Luca ePatanè

2012-08-01

Full Text Available Insects carry a pair of antennae on their head: multimodal sensory organs that serve a wide range of sensory-guided behaviours. During locomotion, antennae are involved in near-range orientation, for example in detecting, localising, 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 localisation in a polar coordinate system. Finally, the damping behaviour 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 localisation 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 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 factorisation. 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

Nanowire FET Based Neural Element for Robotic Tactile Sensing Skin

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William Taube Navaraj

2017-09-01

Full Text Available 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.

Vision affects tactile target and distractor processing even when space is task-irrelevant

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Ann-Katrin eWesslein

2014-02-01

Full Text Available The human brain is adapted to integrate the information from multiple sensory modalities into coherent, robust representations of the objects and events in the external world. A large body of empirical research has demonstrated the ubiquitous nature of the interactions that take place between vision and touch, with the former typically dominating over the latter. Many studies have investigated the influence of visual stimuli on the processing of tactile stimuli (and vice versa. Other studies, meanwhile, have investigated the effect of directing a participant’s gaze either toward or else away from the body-part receiving the target tactile stimulation. Other studies, by contrast, have compared performance in those conditions in which the participant’s eyes have been open versus closed. We start by reviewing the research that has been published to date demonstrating the influence of vision on the processing of tactile targets, that is, on those stimuli that have to be attended or responded to. We outline that many – but not all – of the visuotactile interactions that have been observed to date may be attributable to the direction of spatial attention. We then move on to focus on the crossmodal influence of vision, as well as of the direction of gaze, on the processing of tactile distractors. We highlight the results of those studies demonstrating the influence of vision, rather than gaze direction (i.e., the direction of overt spatial attention, on tactile distractor processing (e.g., tactile variants of the negative-priming or flanker task. The conclusion is that no matter how vision of a tactile distractor is engaged, the result would appear to be the same, namely that tactile distractors are processed more thoroughly.

Effects of electrode size and spacing on sensory modalities in the phantom thumb perception area for the forearm amputees.

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Li, P; Chai, G H; Zhu, K H; Lan, N; Sui, X H

2015-01-01

Tactile sensory feedback plays a key role in accomplishing the dexterous manipulation of prosthetic hands for the amputees, and the non-invasive transcutaneous electrical nerve stimulation (TENS) of the phantom finger perception (PFP) area would be an effective way to realize sensory feedback clinically. In order to realize the high-spatial-resolution tactile sensory feedback in the PFP region, we investigated the effects of electrode size and spacing on the tactile sensations for potentially optimizing the surface electrode array configuration. Six forearm-amputated subjects were recruited in the psychophysical studies. With the diameter of the circular electrode increasing from 3 mm to 12 mm, the threshold current intensity was enhanced correspondingly under different sensory modalities. The smaller electrode could potentially lead to high sensation spatial resolution. Whereas, the smaller the electrode, the less the number of sensory modalities. For an Φ-3 mm electrode, it is even hard for the subject to perceive any perception modalities under normal stimulating current. In addition, the two-electrode discrimination distance (TEDD) in the phantom thumb perception area decreased with electrode size decreasing in two directions of parallel or perpendicular to the forearm. No significant difference of TEDD existed along the two directions. Studies in this paper would guide the configuration optimization of the TENS electrode array for potential high spatial-resolution sensory feedback.

Topographic generalization of tactile perceptual learning.

Science.gov (United States)

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.

Emerging Role of Sensory Perception in Aging and Metabolism.

Science.gov (United States)

Riera, Celine E; Dillin, Andrew

2016-05-01

Sensory perception comprises gustatory (taste) and olfactory (smell) modalities as well as somatosensory (pain, heat, and tactile mechanosensory) inputs, which are detected by a multitude of sensory receptors. These sensory receptors are contained in specialized ciliated neurons where they detect changes in environmental conditions and participate in behavioral decisions ranging from food choice to avoiding harmful conditions, thus insuring basic survival in metazoans. Recent genetic studies, however, indicate that sensory perception plays additional physiological functions, notably influencing energy homeostatic processes and longevity through neuronal circuits originating from sensory tissues. Here we review how these findings are redefining metabolic signaling and establish a prominent role of sensory neuroendocrine processes in controlling health span and lifespan, with a goal of translating this knowledge towards managing age-associated diseases. Copyright © 2016. Published by Elsevier Ltd.

Nogo receptor 1 limits tactile task performance independent of basal anatomical plasticity.

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Jennifer I Park

Full Text Available The genes that govern how experience refines neural circuitry and alters synaptic structural plasticity are poorly understood. The nogo-66 receptor 1 gene (ngr1 is one candidate that may restrict the rate of learning as well as basal anatomical plasticity in adult cerebral cortex. To investigate if ngr1 limits the rate of learning we tested adult ngr1 null mice on a tactile learning task. Ngr1 mutants display greater overall performance despite a normal rate of improvement on the gap-cross assay, a whisker-dependent learning paradigm. To determine if ngr1 restricts basal anatomical plasticity in the associated sensory cortex, we repeatedly imaged dendritic spines and axonal varicosities of both constitutive and conditional adult ngr1 mutant mice in somatosensory barrel cortex for two weeks through cranial windows with two-photon chronic in vivo imaging. Neither constant nor acute deletion of ngr1 affected turnover or stability of dendritic spines or axonal boutons. The improved performance on the gap-cross task is not attributable to greater motor coordination, as ngr1 mutant mice possess a mild deficit in overall performance and a normal learning rate on the rotarod, a motor task. Mice lacking ngr1 also exhibit normal induction of tone-associated fear conditioning yet accelerated fear extinction and impaired consolidation. Thus, ngr1 alters tactile and motor task performance but does not appear to limit the rate of tactile or motor learning, nor determine the low set point for synaptic turnover in sensory cortex.

Tactile information processing in primate hand somatosensory cortex (S1) during passive arm movement.

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Song, Weiguo; Francis, Joseph Thachil

2013-11-01

Motor output mostly depends on sensory input, which also can be affected by action. To further our understanding of how tactile information is processed in the primary somatosensory cortex (S1) in dynamic environments, we recorded neural responses to tactile stimulation of the hand in three awake monkeys under arm/hand passive movement and rest. We found that neurons generally responded to tactile stimulation under both conditions and were modulated by movement: with a higher baseline firing rate, a suppressed peak rate, and a smaller dynamic range during passive movement than during rest, while the area under the response curve was stable across these two states. By using an information theory-based method, the mutual information between tactile stimulation and neural responses was quantified with rate and spatial coding models under the two conditions. The two potential encoding models showed different contributions depending on behavioral contexts. Tactile information encoded with rate coding from individual units was lower than spatial coding of unit pairs, especially during movement; however, spatial coding had redundant information between unit pairs. Passive movement regulated the mutual information, and such regulation might play different roles depending on the encoding strategies used. The underlying mechanisms of our observation most likely come from a bottom-up strategy, where neurons in S1 were regulated through the activation of the peripheral tactile/proprioceptive receptors and the interactions between these different types of information.

Accelerating Early Language Development with Multi-Sensory Training

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Bjorn, Piia M.; Kakkuri, Irma; Karvonen, Pirkko; Leppanen, Paavo H. T.

2012-01-01

This paper reports the outcome of a multi-sensory intervention on infant language skills. A programme titled "Rhyming Game and Exercise Club", which included kinaesthetic-tactile mother-child rhyming games performed in natural joint attention situations, was intended to accelerate Finnish six- to eight-month-old infants' language development. The…

[Neurophysiological investigations of information processing in the somato-sensory system].

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Kunesch, E

2009-08-01

The ability of the human hand to perform complex sensorimotor tasks such as tactile exploration and grasping is based on 1. exact encoding of somatosensory information by cutaneous mechanoreceptors, 2. elaborated processing of afferent signals in somatosensory relay stations and cortex fields, 3. rapid and effective interaction of sensory feedback with motor programs, and 4. different modes of sensory control, which can be switched over. (c) Georg Thieme Verlag KG Stuttgart-New York.

Cognitive and tactile factors affecting human haptic performance in later life.

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Tobias Kalisch

Full Text Available BACKGROUND: Vision and haptics are the key modalities by which humans perceive objects and interact with their environment in a target-oriented manner. Both modalities share higher-order neural resources and the mechanisms required for object exploration. Compared to vision, the understanding of haptic information processing is still rudimentary. Although it is known that haptic performance, similar to many other skills, decreases in old age, the underlying mechanisms are not clear. It is yet to be determined to what extent this decrease is related to the age-related loss of tactile acuity or cognitive capacity. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the haptic performance of 81 older adults by means of a cross-modal object recognition test. Additionally, we assessed the subjects' tactile acuity with an apparatus-based two-point discrimination paradigm, and their cognitive performance by means of the non-verbal Raven-Standard-Progressive matrices test. As expected, there was a significant age-related decline in performance on all 3 tests. With the exception of tactile acuity, this decline was found to be more distinct in female subjects. Correlation analyses revealed a strong relationship between haptic and cognitive performance for all subjects. Tactile performance, on the contrary, was only significantly correlated with male subjects' haptic performance. CONCLUSIONS: Haptic object recognition is a demanding task in old age, especially when it comes to the exploration of complex, unfamiliar objects. Our data support a disproportionately higher impact of cognition on haptic performance as compared to the impact of tactile acuity. Our findings are in agreement with studies reporting an increase in co-variation between individual sensory performance and general cognitive functioning in old age.

Supralinear and Supramodal Integration of Visual and Tactile Signals in Rats: Psychophysics and Neuronal Mechanisms.

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Nikbakht, Nader; Tafreshiha, Azadeh; Zoccolan, Davide; Diamond, Mathew E

2018-02-07

To better understand how object recognition can be triggered independently of the sensory channel through which information is acquired, we devised a task in which rats judged the orientation of a raised, black and white grating. They learned to recognize two categories of orientation: 0° ± 45° ("horizontal") and 90° ± 45° ("vertical"). Each trial required a visual (V), a tactile (T), or a visual-tactile (VT) discrimination; VT performance was better than that predicted by optimal linear combination of V and T signals, indicating synergy between sensory channels. We examined posterior parietal cortex (PPC) and uncovered key neuronal correlates of the behavioral findings: PPC carried both graded information about object orientation and categorical information about the rat's upcoming choice; single neurons exhibited identical responses under the three modality conditions. Finally, a linear classifier of neuronal population firing replicated the behavioral findings. Taken together, these findings suggest that PPC is involved in the supramodal processing of shape. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Heterogeneous sensory processing in persistent postherniotomy pain

DEFF Research Database (Denmark)

Aasvang, Eske Kvanner; Brandsborg, Birgitte; Jensen, Troels Staehelin

2010-01-01

hinders evaluation of potential subgroups for further investigation and/or treatment allocation. Thus we used a standardized QST protocol to evaluate sensory functions in PPP and pain-free control patients, to allow individual sensory characterization of pain patients from calculated Z-values. Seventy PPP...... patients with pain related impairment of everyday activities were compared with normative data from 40 pain-free postherniotomy patients operated>1 year previously. Z-values showed a large variation in sensory disturbances ranging from pronounced detection hypoesthesia (Z=6, cold) to pain hyperalgesia (Z......=-8, pressure). Hyperalgesia for various modalities were found in 80% of patients, with pressure hyperalgesia in approximately 65%, and cutaneous (mechanical or thermal) hyperalgesia in approximately 35% of patients. The paradoxical combination of tactile hypoesthesia and hyperalgesia was seen...

Preferred chewing side-dependent two-point discrimination and cortical activation pattern of tactile tongue sensation.

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Minato, Akiko; Ono, Takashi; Miyamoto, Jun J; Honda, Ei-ichi; Kurabayashi, Tohru; Moriyama, Keiji

2009-10-12

Although tactile feedback from the tongue should contribute to habitual chewing, it is unclear how the sensation of the tongue and its projection to the central nervous system differ with regard to the preferred chewing side (PCS). The purpose of this study was to investigate (1) whether the sensory threshold of the tongue differed according to the side and (2) whether the pattern of hemispheric cortical activation by tactile tongue stimulation differed, with special attention to the PCS. Twelve healthy adults participated in the study. The PCS was determined with a mandibular kinesiograph. In the behavioral study, the mean thresholds for two-point discrimination (TPD) in the anterior, canine and posterior regions on both sides of the tongue, and those between PCS and non-PCS in each region were statistically compared. In the functional magnetic resonance imaging study, tactile stimulation was delivered to either side of the tongue with acrylic balls via a mandibular splint. The runs were measured with a T2*-weighted gradient echo-type echo planar imaging sequence in a 1.5T scanner. Activated voxel numbers in the bilateral primary somatosensory cortex (S1) were statistically compared. The threshold of TPD increased in the order of the anterior, canine and posterior regions. Moreover, this threshold was significantly smaller on the PCS than on the non-PCS in both the canine and posterior regions. Moreover, the number of activated voxels in S1 contralateral to the PCS was significantly greater than that in S1 contralateral to the non-PCS. The present study shows that the PCS is associated with asymmetric tactile sensation and cortical activation of the tongue. The sensory acuity of the tongue on the PCS may play an important role in functional coupling between the jaw and tongue to maximize the efficiency of chewing.

Discrimination of Dynamic Tactile Contact by Temporally Precise Event Sensing in Spiking Neuromorphic Networks.

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Lee, Wang Wei; Kukreja, Sunil L; Thakor, Nitish V

2017-01-01

This paper presents a neuromorphic tactile encoding methodology that utilizes a temporally precise event-based representation of sensory signals. We introduce a novel concept where touch signals are characterized as patterns of millisecond precise binary events to denote pressure changes. This approach is amenable to a sparse signal representation and enables the extraction of relevant features from thousands of sensing elements with sub-millisecond temporal precision. We also proposed measures adopted from computational neuroscience to study the information content within the spiking representations of artificial tactile signals. Implemented on a state-of-the-art 4096 element tactile sensor array with 5.2 kHz sampling frequency, we demonstrate the classification of transient impact events while utilizing 20 times less communication bandwidth compared to frame based representations. Spiking sensor responses to a large library of contact conditions were also synthesized using finite element simulations, illustrating an 8-fold improvement in information content and a 4-fold reduction in classification latency when millisecond-precise temporal structures are available. Our research represents a significant advance, demonstrating that a neuromorphic spatiotemporal representation of touch is well suited to rapid identification of critical contact events, making it suitable for dynamic tactile sensing in robotic and prosthetic applications.

Vibrotactile sensory substitution elicits feeling of ownership of an alien hand.

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Marco D'Alonzo

Full Text Available Tactile feedback plays a key role in the attribution of a limb to the self and in the motor control of grasping and manipulation. However, due to technological limits, current prosthetic hands do not provide amputees with cutaneous touch feedback. Recent findings showed that amputees can be tricked into experiencing an alien rubber hand as part of their own body, by applying synchronous touches to the stump which is out of view, and to the rubber hand in full view. It was suggested that similar effects could be achieved by using a prosthesis with touch sensors that provides synchronous cutaneous feedback through an array of tactile stimulators on the stump. Such a prosthesis holds the potential to be easily incorporated within one's body scheme, because it would reproduce the perceptual illusion in everyday usage. We propose to use sensory substitution--specifically vibrotactile--to address this issue, as current haptic technology is still too bulky and inefficient. In this basic study we addressed the fundamental question of whether visuo-tactile modality mismatch promotes self-attribution of a limb, and to what extent compared to a modality-matched paradigm, on normally-limbed subjects. We manipulated visuo-tactile stimulations, comprising combinations of modality matched, modality mismatched, synchronous and asynchronous stimulations, in a set of experiments fashioned after the Rubber Hand Illusion. Modality mismatched stimulation was provided using a keypad-controlled vibrotactile display. Results from three independent measures of embodiment (questionnaires, pointing tests and skin conductance responses indicate that vibrotactile sensory substitution can be used to induce self-attribution of a rubber hand when synchronous but modality-conflicting visuo-tactile stimulation is delivered to the biological finger pads and to the equivalent rubber hand phalanges.

Integration of Fiber-Optic Sensor Arrays into a Multi-Modal Tactile Sensor Processing System for Robotic End-Effectors

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Peter Kampmann

2014-04-01

Full Text Available With the increasing complexity of robotic missions and the development towards long-term autonomous systems, the need for multi-modal sensing of the environment increases. Until now, the use of tactile sensor systems has been mostly based on sensing one modality of forces in the robotic end-effector. The use of a multi-modal tactile sensory system is motivated, which combines static and dynamic force sensor arrays together with an absolute force measurement system. This publication is focused on the development of a compact sensor interface for a fiber-optic sensor array, as optic measurement principles tend to have a bulky interface. Mechanical, electrical and software approaches are combined to realize an integrated structure that provides decentralized data pre-processing of the tactile measurements. Local behaviors are implemented using this setup to show the effectiveness of this approach.

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

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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.

Supramodal theta, gamma, and sustained fields predict modality-specific modulations of alpha and beta oscillations during visual and tactile working memory

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Ede, F.L. van; Jensen, O.; Maris, E.G.G.

2017-01-01

Flexible control over currently relevant sensory representations is an essential feature of primate cognition. We investigated the neurophysiological bases of such flexible control in humans during an intermodal working memory task in which participants retained visual or tactile sequences. Using

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

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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

High-Speed Tactile Sensing for Array-Type Tactile Sensor and Object Manipulation Based on Tactile Information

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Wataru Fukui

2011-01-01

Full Text Available We have developed a universal robot hand with tactile and other sensors. An array-type tactile sensor is crucial for dexterous manipulation of objects using a robotic hand, since this sensor can measure the pressure distribution on finger pads. The sensor has a very high resolution, and the shape of a grasped object can be classified by using this sensor. The more the number of measurement points provided, the higher the accuracy of the classification, but with a corresponding lengthening of the measurement cycle. In this paper, the problem of slow response time is resolved by using software for an array-type tactile sensor with high resolution that emulates the human sensor system. The validity of the proposed method is demonstrated through experiments.

Tactile score a knowledge media for tactile sense

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Suzuki, Yasuhiro

2014-01-01

This book deals with one of the most novel advances in natural computing, namely, in the field of tactile sense analysis. Massage, which provides relaxation and stimulation for human beings, is analyzed in this book for the first time by encoding the motions and tactile senses involved. The target audience is not limited to researchers who are interested in natural computing but also includes those working in ergonomic design, biomedical engineering, Kansei engineering, and cognitive science.

Perceiving space and optical cues via a visuo-tactile sensory substitution system: a methodological approach for training of blind subjects for navigation.

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Segond, Hervé; Weiss, Déborah; Kawalec, Magdalena; Sampaio, Eliana

2013-01-01

A methodological approach to perceptual learning was used to allow both early blind subjects (experimental group) and blindfolded sighted subjects (control group) to experience optical information and spatial phenomena, on the basis of visuo-tactile information transmitted by a 64-taxel pneumatic sensory substitution device. The learning process allowed the subjects to develop abilities in spatial localisation, shape recognition (with generalisation to different points of view), and monocular depth cue interpretation. During the training phase, early blind people initially experienced more difficulties than blindfolded sighted subjects (having previous perceptual experience of perspective) with interpreting and using monocular depth cues. The amelioration of the performance for all blind subjects during training sessions and the quite similar level of performance reached by two groups in the final navigation tasks suggested that early blind people were able to develop and apply cognitive understanding of depth cues. Both groups showed generalisation of the learning from the initial phases to cue identification in the maze, and subjectively experienced shapes facing them. Subjects' performance depended not only on their perceptual experience but also on their previous spatial competencies.

Clinical neurophysiology and quantitative sensory testing in the investigation of orofacial pain and sensory function.

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Jääskeläinen, Satu K

2004-01-01

Chronic orofacial pain represents a diagnostic and treatment challenge for the clinician. Some conditions, such as atypical facial pain, still lack proper diagnostic criteria, and their etiology is not known. The recent development of neurophysiological methods and quantitative sensory testing for the examination of the trigeminal somatosensory system offers several tools for diagnostic and etiological investigation of orofacial pain. This review presents some of these techniques and the results of their application in studies on orofacial pain and sensory dysfunction. Clinical neurophysiological investigation has greater diagnostic accuracy and sensitivity than clinical examination in the detection of the neurogenic abnormalities of either peripheral or central origin that may underlie symptoms of orofacial pain and sensory dysfunction. Neurophysiological testing may also reveal trigeminal pathology when magnetic resonance imaging has failed to detect it, so these methods should be considered complementary to each other in the investigation of orofacial pain patients. The blink reflex, corneal reflex, jaw jerk, sensory neurography of the inferior alveolar nerve, and the recording of trigeminal somatosensory-evoked potentials with near-nerve stimulation have all proved to be sensitive and reliable in the detection of dysfunction of the myelinated sensory fibers of the trigeminal nerve or its central connections within the brainstem. With appropriately small thermodes, thermal quantitative sensory testing is useful for the detection of trigeminal small-fiber dysfunction (Adelta and C). In neuropathic conditions, it is most sensitive to lesions causing axonal injury. By combining different techniques for investigation of the trigeminal system, an accurate topographical diagnosis and profile of sensory fiber pathology can be determined. Neurophysiological and quantitative sensory tests have already highlighted some similarities among various orofacial pain conditions

Learning Touch Preferences with a Tactile Robot Using Dopamine Modulated STDP in a Model of Insular Cortex

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Ting-Shuo eChou

2015-07-01

Full Text Available 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, the plasticity (i.e., STDP in primary somatosensory cortex and insular cortex 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.

A clinician-administered observation and corresponding caregiver interview capturing DSM-5 sensory reactivity symptoms in children with ASD.

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Siper, Paige M; Kolevzon, Alexander; Wang, A Ting; Buxbaum, Joseph D; Tavassoli, Teresa

2017-06-01

Sensory reactivity is a new criterion for autism spectrum disorder (ASD) in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). However, there is no consensus on how to reliably measure sensory reactivity, particularly in minimally verbal individuals. The current study is an initial validation of the Sensory Assessment for Neurodevelopmental Disorders (SAND), a novel clinician-administered observation and corresponding caregiver interview that captures sensory symptoms based on DSM-5 criteria for ASD. Eighty children between the ages of 2 and 12 participated in this study; 44 children with ASD and 36 typically developing (TD) children. Sensory reactivity symptoms were measured using the SAND and the already validated Short Sensory Profile (SSP). Initial psychometric properties of the SAND were examined including reliability, validity, sensitivity and specificity. Children with ASD showed significantly more sensory reactivity symptoms compared to TD children across sensory domains (visual, tactile, and auditory) and within sensory subtypes (hyperreactivity, hyporeactivity and seeking). The SAND showed strong internal consistency, inter-rater reliability and test-retest reliability, high sensitivity (95.5%) and specificity (91.7%), and strong convergent validity with the SSP. The SAND provides a novel method to characterize sensory reactivity symptoms based on DSM-5 criteria for ASD. This is the first known sensory assessment that combines a clinician-administered observation and caregiver interview to optimally capture sensory phenotypes characteristic of individuals with neurodevelopmental disorders. The SAND offers a beneficial new tool for both research and clinical purposes and has the potential to meaningfully enhance gold-standard assessment of ASD. Autism Res 2017, 10: 1133-1140. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Textiles Objective and Sensory Evaluation in Rapid Prototyping

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Eugenija STRAZDIENE

2011-11-01

Full Text Available Most consumer purchases nowadays are driven by sensory attraction and good feeling. From this standpoint textile and fashion industries need new methods to evaluate fabric quality and to respond to consumer expectations. Recently the implementation of sensory analysis in the process of material characterization has drawn much international attention. So, the aim of the research was to find dependencies between the results of sensory analysis and objective fabric behaviour evaluation performed using KES-F and Griff-Tester devices. The later method was developed at Kaunas University of Technology and is based on fabric extraction through a rounded hole, thus describing the behaviour of textile materials and their tactile properties by one complex criterion.http://dx.doi.org/10.5755/j01.ms.17.4.778

Application of vibration to wrist and hand skin affects fingertip tactile sensation

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Lakshminarayanan, Kishor; Lauer, Abigail W; Ramakrishnan, Viswanathan; Webster, John G; Seo, Na Jin

2015-01-01

A recent study showed that fingertip pads’ tactile sensation can improve by applying imperceptible white-noise vibration to the skin at the wrist or dorsum of the hand in stroke patients. This study further examined this behavior by investigating the effect of both imperceptible and perceptible white-noise vibration applied to different locations within the distal upper extremity on the fingertip pads’ tactile sensation in healthy adults. In 12 healthy adults, white-noise vibration was applied to one of four locations (dorsum hand by the second knuckle, thenar and hypothenar areas, and volar wrist) at one of four intensities (zero, 60%, 80%, and 120% of the sensory threshold for each vibration location), while the fingertip sensation, the smallest vibratory signal that could be perceived on the thumb and index fingertip pads, was assessed. Vibration intensities significantly affected the fingertip sensation (P sensation (P sensation (P sensation (P > 0.01), all compared with the zero vibration condition. This effect with vibration intensity conforms to the stochastic resonance behavior. Nonspecificity to the vibration location suggests the white-noise vibration affects higher level neuronal processing for fingertip sensing. Further studies are needed to elucidate the neural pathways for distal upper extremity vibration to impact fingertip pad tactile sensation. PMID:26177959

Tactile stimulation interventions: influence of stimulation parameters on sensorimotor behavior and neurophysiological correlates in healthy and clinical samples.

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Parianen Lesemann, Franca H; Reuter, Eva-Maria; Godde, Ben

2015-04-01

The pure exposure to extensive tactile stimulation, without the requirement of attention or active training, has been revealed to enhance sensorimotor functioning presumably due to an induction of plasticity in the somatosensory cortex. The induced effects, including increased tactile acuity and manual dexterity have repeatedly been observed in basic as well as clinical research. However, results vary greatly in respect to the strength and direction of the effects on the behavioral and on the brain level. Multiple evidences show that differences in the stimulation protocols (e.g., two vs. multiple stimulation sites) and parameters (e.g., duration, frequency, and amplitude) might contribute to this variability of effects. Nevertheless, stimulation protocols have not been comprehensively compared yet. Identifying favorable parameters for tactile stimulation interventions is especially important because of its possible application as a treatment option for patients suffering from sensory loss, maladaptive plasticity, or certain forms of motor impairment. This review aims to compare the effects of different tactile stimulation protocols and to assess possible implications for tactile interventions. Our goal is to identify ways of optimizing stimulation protocols to improve sensorimotor performance. To this end, we reviewed research on tactile stimulation in the healthy population, with a focus on the effectiveness of the applied parameters regarding psychophysiological measures. We discuss the association of stimulation-induced changes on the behavioral level with alterations in neural representations and response characteristics. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tactile-dependant corticomotor facilitation is influenced by discrimination performance in seniors

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Tremblay François

2010-03-01

Full Text Available Abstract Background Active contraction leads to facilitation of motor responses evoked by transcranial magnetic stimulation (TMS. In small hand muscles, motor facilitation is known to be also influenced by the nature of the task. Recently, we showed that corticomotor facilitation was selectively enhanced when young participants actively discriminated tactile symbols with the tip of their index or little finger. This tactile-dependant motor facilitation reflected, for the large part, attentional influences associated with performing tactile discrimination, since execution of a concomitant distraction task abolished facilitation. In the present report, we extend these observations to examine the influence of age on the ability to produce extra motor facilitation when the hand is used for sensory exploration. Methods Corticomotor excitability was tested in 16 healthy seniors (58-83 years while they actively moved their right index finger over a surface under two task conditions. In the tactile discrimination (TD condition, participants attended to the spatial location of two tactile symbols on the explored surface, while in the non discrimination (ND condition, participants simply moved their finger over a blank surface. Changes in amplitude, in latency and in the silent period (SP duration were measured from recordings of motor evoked potentials (MEP in the right first dorsal interosseous muscle in response to TMS of the left motor cortex. Results Healthy seniors exhibited widely varying levels of performance with the TD task, older age being associated with lower accuracy and vice-versa. Large inter-individual variations were also observed in terms of tactile-specific corticomotor facilitation. Regrouping seniors into higher (n = 6 and lower performance groups (n = 10 revealed a significant task by performance interaction. This latter interaction reflected differences between higher and lower performance groups; tactile-related facilitation being

Hysteresis as an Implicit Prior in Tactile Spatial Decision Making

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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

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

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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.

Recent Progress in Technologies for Tactile Sensors

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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

Attenuation of Self-Generated Tactile Sensations is Predictive, not Postdictive.

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2006-01-01

Full Text Available When one finger touches the other, the resulting tactile sensation is perceived as weaker than the same stimulus externally imposed. This attenuation of sensation could result from a predictive process that subtracts the expected sensory consequences of the action, or from a postdictive process that alters the perception of sensations that are judged after the event to be self-generated. In this study we observe attenuation even when the fingers unexpectedly fail to make contact, supporting a predictive process. This predictive attenuation of self-generated sensation may have evolved to enhance the perception of sensations with an external cause.

Attenuation of self-generated tactile sensations is predictive, not postdictive.

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Paul M Bays

2006-02-01

Full Text Available When one finger touches the other, the resulting tactile sensation is perceived as weaker than the same stimulus externally imposed. This attenuation of sensation could result from a predictive process that subtracts the expected sensory consequences of the action, or from a postdictive process that alters the perception of sensations that are judged after the event to be self-generated. In this study we observe attenuation even when the fingers unexpectedly fail to make contact, supporting a predictive process. This predictive attenuation of self-generated sensation may have evolved to enhance the perception of sensations with an external cause.

Trigeminal pain and quantitative sensory testing in painful peripheral diabetic neuropathy.

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Arap, Astrid; Siqueira, Silvia R D T; Silva, Claudomiro B; Teixeira, Manoel J; Siqueira, José T T

2010-07-01

To evaluate patients with Diabetes Mellitus type 2 and painful peripheral neuropathy in order to investigate oral complaints and facial somatosensory findings. Case-control study; 29 patients (12 women, mean age 57.86 yo) with Diabetes Mellitus type 2 and 31 age-gender-matched controls were evaluated with a standardized protocol for general characteristics, orofacial pain, research diagnostic criteria for temporomandibular disorders, visual analogue scale and McGill Pain questionnaire, and a systematic protocol of quantitative sensory testing for bilateral facial sensitivity at the areas innervated by the trigeminal branches, which included the thermal detection by ThermoSensi 2, tactile evaluation with vonFrey filaments, and superficial pain thresholds with a superficial algometer (Micromar). Statistical analysis was performed with Wilcoxon, chi-square, confidence intervals and Spearman (ppain was reported by 55.2% of patients, and the most common descriptor was fatigue (50%); 17.2% had burning mouth. Myofascial temporomandibular disorders were diagnosed in 9 (31%) patients. The study group showed higher sensory thresholds of pain at the right maxillary branch (p=0.017) but sensorial differences were not associated with pain (p=0.608). Glycemia and HbA(1c) were positively correlated with the quantitative sensory testing results of pain (ppain thresholds were correlated with higher glycemia and glycated hemoglobin (p=0.027 and p=0.026). There was a high prevalence of orofacial pain and burning mouth was the most common complaint. The association of loss of pain sensation and higher glycemia and glycated hemoglobin can be of clinical use for the follow-up of DM complications. 2010 Elsevier Ltd. All rights reserved.

Diagnostic Accuracy of Clinical Methods for Detection of Diabetic Sensory Neuropathy

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Arshad, A. R.; Alvi, K. Y.

2016-01-01

Objective: To determine the accuracy of clinical methods for detection of sensory neuropathy as compared to biothesiometry. Study Design: Cross-sectional analytical study. Place and Duration of Study: 1 Mountain Medical Battalion, Azad Kashmir, from October 2013 to September 2014. Methodology: Patients with type 2 diabetes were enrolled by convenience sampling. Exclusion criteria included other identifiable causes of neuropathy, extensive ulceration of feet, amputated feet, those on treatment for neuropathy and unwilling patients. Average of 3 vibration perception threshold values measured with a biothesiometer on distal hallux was calculated. Ten gm monofilament was used to examine touch sensation over dorsal surfaces of great toes. Vibration sensation was checked over the tips of great toes using 128Hz tuning fork. Ankle jerks were checked bilaterally. Result: Neuropathy (vibration perception threshold > 25 volts) was present in 34 (21.12 percentage) out of 161 patients and 93 (57.76 percentage) were symptomatic. Measures of diagnostic accuracy for monofilament, tuning fork and ankle jerks were: sensitivity 41.18 percentage, 55.88 percentage and 64.71 percentage; specificity 92.91 percentage, 93.70 percentage and 80.31 percentage; positive predictive value (PPV) 60.87 percentage, 70.37 percentage and 46.81 percentage; negative predictive value (NPV) 85.51 percentage, 88.81 percentage and 89.47 percentage; and, diagnostic accuracy 81.99 percentage, 85.71 percentage and 77.02 percentage, respectively. Values for any 1 positive sign, any 2 positive signs or all 3 positive signs were: sensitivity 35.29 percentage, 14.71 percentage and 32.35 percentage; specificity 81.89 percentage, 93.70 percentage and 99.21 percentage; PPV 34.29 percentage, 38.46 percentage and 91.67 percentage; NPV 82.54 percentage, 80.41 percentage and 84.56 percentage; and, diagnostic accuracy 72.05 percentage, 77.02 percentage and 85.09 percentage, respectively. Conclusion: Clinical methods are

Optical-to-Tactile Translator

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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.

System to induce and measure embodiment of an artificial hand with programmable convergent visual and tactile stimuli.

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Benz, Heather L; Sieff, Talia R; Alborz, Mahsa; Kontson, Kimberly; Kilpatrick, Elizabeth; Civillico, Eugene F

2016-08-01

The sense of prosthesis embodiment, or the feeling that the device has been incorporated into a user's body image, may be enhanced by emerging technology such as invasive electrical stimulation for sensory feedback. In turn, prosthesis embodiment may be linked to increased prosthesis use and improved functional outcomes. We describe the development of a tool to assay artificial hand embodiment in a quantitative way in people with intact limbs, and characterize its operation. The system delivers temporally coordinated visual and tactile stimuli at a programmable latency while recording limb temperature. When programmed to deliver visual and tactile stimuli synchronously, recorded latency between the two was 33 ± 24 ms in the final pilot subject. This system enables standardized assays of the conditions necessary for prosthesis embodiment.

The effect of perceptual load on tactile spatial attention: Evidence from event-related potentials.

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Gherri, Elena; Berreby, Fiona

2017-10-15

To investigate whether tactile spatial attention is modulated by perceptual load, behavioural and electrophysiological measures were recorded during two spatial cuing tasks in which the difficulty of the target/non-target discrimination was varied (High and Low load tasks). Moreover, to study whether attentional modulations by load are sensitive to the availability of visual information, the High and Low load tasks were carried out under both illuminated and darkness conditions. ERPs to cued and uncued non-targets were compared as a function of task (High vs. Low load) and illumination condition (Light vs. Darkness). Results revealed that the locus of tactile spatial attention was determined by a complex interaction between perceptual load and illumination conditions during sensory-specific stages of processing. In the Darkness, earlier effects of attention were present in the High load than in the Low load task, while no difference between tasks emerged in the Light. By contrast, increased load was associated with stronger attention effects during later post-perceptual processing stages regardless of illumination conditions. These findings demonstrate that ERP correlates of tactile spatial attention are strongly affected by the perceptual load of the target/non-target discrimination. However, differences between illumination conditions show that the impact of load on tactile attention depends on the presence of visual information. Perceptual load is one of the many factors that contribute to determine the effects of spatial selectivity in touch. Copyright © 2017 Elsevier B.V. All rights reserved.

Functional and Structural Neuroplasticity Induced by Short-Term Tactile Training Based on Braille Reading.

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Debowska, Weronika; Wolak, Tomasz; Nowicka, Anna; Kozak, Anna; Szwed, Marcin; Kossut, Malgorzata

2016-01-01

Neuroplastic changes induced by sensory learning have been recognized within the cortices of specific modalities as well as within higher ordered multimodal areas. The interplay between these areas is not fully understood, particularly in the case of somatosensory learning. Here we examined functional and structural changes induced by short-term tactile training based of Braille reading, a task that requires both significant tactile expertise and mapping of tactile input onto multimodal representations. Subjects with normal vision were trained for 3 weeks to read Braille exclusively by touch and scanned before and after training, while performing a same-different discrimination task on Braille characters and meaningless characters. Functional and diffusion-weighted magnetic resonance imaging sequences were used to assess resulting changes. The strongest training-induced effect was found in the primary somatosensory cortex (SI), where we observed bilateral augmentation in activity accompanied by an increase in fractional anisotropy (FA) within the contralateral SI. Increases of white matter fractional anisotropy were also observed in the secondary somatosensory area (SII) and the thalamus. Outside of somatosensory system, changes in both structure and function were found in i.e., the fusiform gyrus, the medial frontal gyri and the inferior parietal lobule. Our results provide evidence for functional remodeling of the somatosensory pathway and higher ordered multimodal brain areas occurring as a result of short-lasting tactile learning, and add to them a novel picture of extensive white matter plasticity.

Tactile thermal oral stimulation increases the cortical representation of swallowing

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Suntrup Sonja

2009-06-01

Full Text Available Abstract Background Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM and the group analysis of individual SAM data was performed using a permutation test. Results Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition. Conclusion In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery.

Recruitment of occipital cortex during sensory substitution training linked to subjective experience of seeing in people with blindness.

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Tomás Ortiz

Full Text Available Over three months of intensive training with a tactile stimulation device, 18 blind and 10 blindfolded seeing subjects improved in their ability to identify geometric figures by touch. Seven blind subjects spontaneously reported 'visual qualia', the subjective sensation of seeing flashes of light congruent with tactile stimuli. In the latter subjects tactile stimulation evoked activation of occipital cortex on electroencephalography (EEG. None of the blind subjects who failed to experience visual qualia, despite identical tactile stimulation training, showed EEG recruitment of occipital cortex. None of the blindfolded seeing humans reported visual-like sensations during tactile stimulation. These findings support the notion that the conscious experience of seeing is linked to the activation of occipital brain regions in people with blindness. Moreover, the findings indicate that provision of visual information can be achieved through non-visual sensory modalities which may help to minimize the disability of blind individuals, affording them some degree of object recognition and navigation aid.

Recruitment of occipital cortex during sensory substitution training linked to subjective experience of seeing in people with blindness.

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Ortiz, Tomás; Poch, Joaquín; Santos, Juan M; Requena, Carmen; Martínez, Ana M; Ortiz-Terán, Laura; Turrero, Agustín; Barcia, Juan; Nogales, Ramón; Calvo, Agustín; Martínez, José M; Córdoba, José L; Pascual-Leone, Alvaro

2011-01-01

Over three months of intensive training with a tactile stimulation device, 18 blind and 10 blindfolded seeing subjects improved in their ability to identify geometric figures by touch. Seven blind subjects spontaneously reported 'visual qualia', the subjective sensation of seeing flashes of light congruent with tactile stimuli. In the latter subjects tactile stimulation evoked activation of occipital cortex on electroencephalography (EEG). None of the blind subjects who failed to experience visual qualia, despite identical tactile stimulation training, showed EEG recruitment of occipital cortex. None of the blindfolded seeing humans reported visual-like sensations during tactile stimulation. These findings support the notion that the conscious experience of seeing is linked to the activation of occipital brain regions in people with blindness. Moreover, the findings indicate that provision of visual information can be achieved through non-visual sensory modalities which may help to minimize the disability of blind individuals, affording them some degree of object recognition and navigation aid.

Blind Braille readers mislocate tactile stimuli.

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Sterr, Annette; Green, Lisa; Elbert, Thomas

2003-05-01

In a previous experiment, we observed that blind Braille readers produce errors when asked to identify on which finger of one hand a light tactile stimulus had occurred. With the present study, we aimed to specify the characteristics of this perceptual error in blind and sighted participants. The experiment confirmed that blind Braille readers mislocalised tactile stimuli more often than sighted controls, and that the localisation errors occurred significantly more often at the right reading hand than at the non-reading hand. Most importantly, we discovered that the reading fingers showed the smallest error frequency, but the highest rate of stimulus attribution. The dissociation of perceiving and locating tactile stimuli in the blind suggests altered tactile information processing. Neuroplasticity, changes in tactile attention mechanisms as well as the idea that blind persons may employ different strategies for tactile exploration and object localisation are discussed as possible explanations for the results obtained.

Correlation of neural activity with behavioral kinematics reveals distinct sensory encoding and evidence accumulation processes during active tactile sensing.

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Delis, Ioannis; Dmochowski, Jacek P; Sajda, Paul; Wang, Qi

2018-03-23

Many real-world decisions rely on active sensing, a dynamic process for directing our sensors (e.g. eyes or fingers) across a stimulus to maximize information gain. Though ecologically pervasive, limited work has focused on identifying neural correlates of the active sensing process. In tactile perception, we often make decisions about an object/surface by actively exploring its shape/texture. Here we investigate the neural correlates of active tactile decision-making by simultaneously measuring electroencephalography (EEG) and finger kinematics while subjects interrogated a haptic surface to make perceptual judgments. Since sensorimotor behavior underlies decision formation in active sensing tasks, we hypothesized that the neural correlates of decision-related processes would be detectable by relating active sensing to neural activity. Novel brain-behavior correlation analysis revealed that three distinct EEG components, localizing to right-lateralized occipital cortex (LOC), middle frontal gyrus (MFG), and supplementary motor area (SMA), respectively, were coupled with active sensing as their activity significantly correlated with finger kinematics. To probe the functional role of these components, we fit their single-trial-couplings to decision-making performance using a hierarchical-drift-diffusion-model (HDDM), revealing that the LOC modulated the encoding of the tactile stimulus whereas the MFG predicted the rate of information integration towards a choice. Interestingly, the MFG disappeared from components uncovered from control subjects performing active sensing but not required to make perceptual decisions. By uncovering the neural correlates of distinct stimulus encoding and evidence accumulation processes, this study delineated, for the first time, the functional role of cortical areas in active tactile decision-making. Copyright © 2018 Elsevier Inc. All rights reserved.

The neural network involved in a bimanual tactile-tactile matching discrimination task: a functional imaging study at 3 T

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Habas, Christophe; Cabanis, Emmanuel A. [UPMC Paris 6, Service de NeuroImagerie, Hopital des Quinze-Vingts, Paris (France)

2007-08-15

The cerebral and cerebellar network involved in a bimanual object recognition was studied in blood oxygenation dependent level functional magnetic resonance imaging (fMRI). Nine healthy right-handed volunteers were scanned (1) while performing bilateral finger movements (nondiscrimination motor task), and (2) while performing a bimanual tactile-tactile matching discrimination task using small chess pieces (tactile discrimination task). Extensive activations were specifically observed in the parietal (SII, superior lateral lobule), insular, prefrontal, cingulate and neocerebellar cortices (HVIII), with a left predominance in motor areas, during the tactile discrimination task in contrast to the findings during the nondiscrimination motor task. Bimanual tactile-tactile matching discrimination recruits multiple sensorimotor and associative cerebral and neocerebellar networks (including the cerebellar second homunculus, HVIII), comparable to the neural circuits involved in unimanual tactile object recognition. (orig.)

Prefrontal cortex and somatosensory cortex in tactile crossmodal association: an independent component analysis of ERP recordings.

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Yixuan Ku

2007-08-01

Full Text Available Our previous studies on scalp-recorded event-related potentials (ERPs showed that somatosensory N140 evoked by a tactile vibration in working memory tasks was enhanced when human subjects expected a coming visual stimulus that had been paired with the tactile stimulus. The results suggested that such enhancement represented the cortical activities involved in tactile-visual crossmodal association. In the present study, we further hypothesized that the enhancement represented the neural activities in somatosensory and frontal cortices in the crossmodal association. By applying independent component analysis (ICA to the ERP data, we found independent components (ICs located in the medial prefrontal cortex (around the anterior cingulate cortex, ACC and the primary somatosensory cortex (SI. The activity represented by the IC in SI cortex showed enhancement in expectation of the visual stimulus. Such differential activity thus suggested the participation of SI cortex in the task-related crossmodal association. Further, the coherence analysis and the Granger causality spectral analysis of the ICs showed that SI cortex appeared to cooperate with ACC in attention and perception of the tactile stimulus in crossmodal association. The results of our study support with new evidence an important idea in cortical neurophysiology: higher cognitive operations develop from the modality-specific sensory cortices (in the present study, SI cortex that are involved in sensation and perception of various stimuli.

Contralateral tactile masking between forearms.

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D'Amour, Sarah; Harris, Laurence R

2014-03-01

Masking effects have been demonstrated in which tactile sensitivity is affected when one touch is close to another on the body surface. Such effects are likely a result of local lateral inhibitory circuits that sharpen the spatial tuning of a given tactile receptor. Mutually inhibitory pathways have also been demonstrated between cortical tactile maps of the two halves of the body. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at contralateral locations. Here, we measure the spatial tuning and effect of posture on this contralateral masking effect. Tactile sensitivity was measured on one forearm, while vibrotactile masking stimulation was applied to the opposite arm. Results were compared to sensitivity while vibrotactile stimulation was applied to a control site on the right shoulder. Sensitivity on the forearm was reduced by over 3 dB when the arms were touching and by 0.52 dB when they were held parallel. The masking effect depended on the position of the masking stimulus. Its effectiveness fell off by 1 STD when the stimulus was 29 % of arm length from the corresponding contralateral point. This long-range inhibitory effect in the tactile system suggests a surprisingly intimate relationship between the two sides of the body.

Spatial imagery relies on a sensory independent, though sensory sensitive, functional organization within the parietal cortex: a fMRI study of angle discrimination in sighted and congenitally blind individuals.

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Bonino, Daniela; Ricciardi, Emiliano; Bernardi, Giulio; Sani, Lorenzo; Gentili, Claudio; Vecchi, Tomaso; Pietrini, Pietro

2015-02-01

Although vision offers distinctive information to space representation, individuals who lack vision since birth often show perceptual and representational skills comparable to those found in sighted individuals. However, congenitally blind individuals may result in impaired spatial analysis, when engaging in 'visual' spatial features (e.g., perspective or angle representation) or complex spatial mental abilities. In the present study, we measured behavioral and brain responses using functional magnetic resonance imaging in sighted and congenitally blind individuals during spatial imagery based on a modified version of the mental clock task (e.g., angle discrimination) and a simple recognition control condition, as conveyed across distinct sensory modalities: visual (sighted individuals only), tactile and auditory. Blind individuals were significantly less accurate during the auditory task, but comparable-to-sighted during the tactile task. As expected, both groups showed common neural activations in intraparietal and superior parietal regions across visual and non-visual spatial perception and imagery conditions, indicating the more abstract, sensory independent functional organization of these cortical areas, a property that we named supramodality. At the same time, however, comparisons in brain responses and functional connectivity patterns across experimental conditions demonstrated also a functional lateralization, in a way that correlated with the distinct behavioral performance in blind and sighted individuals. Specifically, blind individuals relied more on right parietal regions, mainly in the tactile and less in the auditory spatial processing. In sighted, spatial representation across modalities relied more on left parietal regions. In conclusions, intraparietal and superior parietal regions subserve supramodal spatial representations in sighted and congenitally blind individuals. Differences in their recruitment across non-visual spatial processing in

Helping students revise disruptive experientially supported ideas about thermodynamics: Computer visualizations and tactile models

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Clark, Douglas; Jorde, Doris

2004-01-01

This study analyzes the impact of an integrated sensory model within a thermal equilibrium visualization. We hypothesized that this intervention would not only help students revise their disruptive experientially supported ideas about why objects feel hot or cold, but also increase their understanding of thermal equilibrium. The analysis synthesizes test data and interviews to measure the impact of this strategy. Results show that students in the experimental tactile group significantly outperform their control group counterparts on posttests and delayed posttests, not only on tactile explanations, but also on thermal equilibrium explanations. Interview transcripts of experimental and control group students corroborate these findings. Discussion addresses improving the tactile model as well as application of the strategy to other science topics. The discussion also considers possible incorporation of actual kinetic or thermal haptic feedback to reinforce the current audio and visual feedback of the visualization. This research builds on the conceptual change literature about the nature and role of students' experientially supported ideas as well as our understanding of curriculum and visualization design to support students in learning about thermodynamics, a science topic on which students perform poorly as shown by the National Assessment of Educational Progress (NAEP) and Third International Mathematics and Science Study (TIMSS) studies.

Touching lips and hearing fingers: effector-specific congruency between tactile and auditory stimulation modulates N1 amplitude and alpha desynchronization.

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Shen, Guannan; Meltzoff, Andrew N; Marshall, Peter J

2018-01-01

Understanding the interactions between audition and sensorimotor processes is of theoretical importance, particularly in relation to speech processing. Although one current focus in this area is on interactions between auditory perception and the motor system, there has been less research on connections between the auditory and somatosensory modalities. The current study takes a novel approach to this omission by examining specific auditory-tactile interactions in the context of speech and non-speech sound production. Electroencephalography was used to examine brain responses when participants were presented with speech syllables (a bilabial sound /pa/ and a non-labial sound /ka/) or finger-snapping sounds that were simultaneously paired with tactile stimulation of either the lower lip or the right middle finger. Analyses focused on the sensory-evoked N1 in the event-related potential and the extent of alpha band desynchronization elicited by the stimuli. N1 amplitude over fronto-central sites was significantly enhanced when the bilabial /pa/ sound was paired with tactile lip stimulation and when the finger-snapping sound was paired with tactile stimulation of the finger. Post-stimulus alpha desynchronization at central sites was also enhanced when the /pa/ sound was accompanied by tactile stimulation of the lip. These novel findings indicate that neural aspects of somatosensory-auditory interactions are influenced by the congruency between the location of the bodily touch and the bodily origin of a perceived sound.

Sensory processing disorders – diagnostic and therapeutic controversies

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Aneta R. Borkowska

2017-09-01

Full Text Available This article presents the current state of knowledge regarding the controversial issue of sensory integration dysfunction/sensory processing disorder. Symptoms are defined as impairments in the accurate reception and registering of stimuli, differentiation of stimulus intensity, and adequate reactivity to stimulation. They can be of specific character and occur in isolation and can also be a nonspecific element of a clinical picture of another disease entity. Psychophysiological and neuroimaging studies confirm the existence of both a distinct group of children with symptoms of sensory processing disorder diagnosed based on descriptions of behaviours listed in questionnaires and of a specific neurobiological basis of this disorder. In clinical practice, it is of key importance to determine whether behavioural problems observed in children are caused by disorders other than sensory processing disorders. Results of meta-analyses regarding sensory integration therapy are inconclusive and do not allow this form of treatment to be considered fact-based. Future studies with high methodological standards are necessary in order to verify the effectiveness of different forms of sensory integration therapy. Parents should be informed about the existing limitations.

Similar effects of attention directed to acoustic and tactile stimuli on prepulse inhibition of acoustic startle.

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Elden, Ake; Flaten, Magne A

2003-09-01

Prepulse inhibition (PPI) is assumed to index automatic and controlled processing. In three experiments (n= 32, 22, and 30) participants were asked to judge the duration of a prepulse in comparison with a stimulus presented 4000 ms before the prepulse. A distracter was presented simultaneously with the prepulse to increase the cognitive demands of the task. PPI was assessed at stimulus onset asynchronies (SOAs) of 30-150 ms, and 420 ms. The prepulse was either a tone (60 dB) or a tactile stimulus (21 kPa), and startle was elicited by 95 dB white noise. Directing attention to the prepulse increased PPI at SOAs of 60 ms and longer in all experiments, but the sensory modality to which attention was directed played only a minor role. We conclude that directing attention to both acoustic and tactile prepulses increased PPI.

Sensory and cognitive neurophysiology in rats. Part 2: Validation and demonstration.

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Dimitriadis, George; Fransen, Anne M M; Maris, Eric

2014-07-30

We have developed a novel setup for rats that allows for controlled sensory input to an animal engaged in a task while recording both electrophysiological signals and behavioral output. Our setup is described in a companion paper. We validate our setup by replicating (1) the functionally nonspecific spread of neural activity following tactile stimulation, and (2) the effects of anesthesia on the tactile evoked responses. We also demonstrate for the first time that the ECoG can be used to record evoked responses in a signal that reflects neural output (spiking activity), and illustrate the usefulness of our setup by demonstrating that these evoked responses are modulated by both the phase of pre-stimulus oscillations and by expectation. Compared with high-density wire recordings, micro-ECoG offers a much more stable signal without readjustments, and a much better scalability. Compared with extracranial and regular ECoG recordings, micro-ECoG allows us to measure signals that reflect both neural input and neural output. For sensory and cognitive research, our setup provides a unique combination of possibilities that cannot be achieved in other setups for rodents. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional Alterations of Postcentral Gyrus Modulated by Angry Facial Expressions during Intraoral Tactile Stimuli in Patients with Burning Mouth Syndrome: A Functional Magnetic Resonance Imaging Study

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Yoshino, Atsuo; Okamoto, Yasumasa; Doi, Mitsuru; Okada, Go; Takamura, Masahiro; Ichikawa, Naho; Yamawaki, Shigeto

2017-01-01

Previous findings suggest that negative emotions could influence abnormal sensory perception in burning mouth syndrome (BMS). However, few studies have investigated the underlying neural mechanisms associated with BMS. We examined activation of brain regions in response to intraoral tactile stimuli when modulated by angry facial expressions. We performed functional magnetic resonance imaging on a group of 27 BMS patients and 21 age-matched healthy controls. Tactile stimuli were presented during different emotional contexts, which were induced via the continuous presentation of angry or neutral pictures of human faces. BMS patients exhibited higher tactile ratings and greater activation in the postcentral gyrus during the presentation of tactile stimuli involving angry faces relative to controls. Significant positive correlations between changes in brain activation elicited by angry facial images in the postcentral gyrus and changes in tactile rating scores by angry facial images were found for both groups. For BMS patients, there was a significant positive correlation between changes in tactile-related activation of the postcentral gyrus elicited by angry facial expressions and pain intensity in daily life. Findings suggest that neural responses in the postcentral gyrus are more strongly affected by angry facial expressions in BMS patients, which may reflect one possible mechanism underlying impaired somatosensory system function in this disorder. PMID:29163243

Functional Alterations of Postcentral Gyrus Modulated by Angry Facial Expressions during Intraoral Tactile Stimuli in Patients with Burning Mouth Syndrome: A Functional Magnetic Resonance Imaging Study

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Atsuo Yoshino

2017-11-01

Full Text Available Previous findings suggest that negative emotions could influence abnormal sensory perception in burning mouth syndrome (BMS. However, few studies have investigated the underlying neural mechanisms associated with BMS. We examined activation of brain regions in response to intraoral tactile stimuli when modulated by angry facial expressions. We performed functional magnetic resonance imaging on a group of 27 BMS patients and 21 age-matched healthy controls. Tactile stimuli were presented during different emotional contexts, which were induced via the continuous presentation of angry or neutral pictures of human faces. BMS patients exhibited higher tactile ratings and greater activation in the postcentral gyrus during the presentation of tactile stimuli involving angry faces relative to controls. Significant positive correlations between changes in brain activation elicited by angry facial images in the postcentral gyrus and changes in tactile rating scores by angry facial images were found for both groups. For BMS patients, there was a significant positive correlation between changes in tactile-related activation of the postcentral gyrus elicited by angry facial expressions and pain intensity in daily life. Findings suggest that neural responses in the postcentral gyrus are more strongly affected by angry facial expressions in BMS patients, which may reflect one possible mechanism underlying impaired somatosensory system function in this disorder.

A Radiation Learning Support System by Tri-sensory Augmented Reality using a Mobile Phone

International Nuclear Information System (INIS)

Shimoda, Hiroshi; Zhao, Yue; Yan, Weida; Ishii, Hirotake

2011-01-01

A radiation learning support system has been developed to support learning basic knowledge of radiation and its influence on the human body by using tri-sensory Augmented Reality (AR) technology with presenting information to visual, auditory and tactile sensation. The system consists of a knowledge learning mode in which learners can learn basic knowledge of radiation and an experience learning mode in which they can virtually experience its influence on the human body under various conditions. As the result of a simple evaluation, it was suggested that the system improves the learners' intuitive understanding, and information presentation to auditory and tactile sensation is more effective than that to visual sensation

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

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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.

Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice.

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Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

2016-01-01

Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

Robotic Tactile Sensing Technologies and System

CERN Document Server

Dahiya, Ravinder S

2013-01-01

Future robots are expected to work closely and interact safely with real-world objects and humans alike. Sense of touch is important in this context, as it helps estimate properties such as shape, texture, hardness, material type and many more; provides action related information, such as slip detection; and helps carrying out actions such as rolling an object between fingers without dropping it. This book presents an in-depth description of the solutions available for gathering tactile data, obtaining aforementioned tactile information from the data and effectively using the same in various robotic tasks. Better integration of tactile sensors on a robot’s body is prerequisite for the effective utilization of tactile data. For this reason, the hardware, software and application related issues (and resulting trade-offs) that must be considered to make tactile sensing an effective component of robotic platforms are discussed in-depth.To this end, human touch sensing has also been explored. The design hints co...

The brain’s response to pleasant touch: an EEG investigation of tactile caressing

Directory of Open Access Journals (Sweden)

Harsimrat eSingh

2014-11-01

Full Text Available Somatosensation as a proximal sense can have a strong impact on our attitude towards physical objects and other human beings. However, relatively little is known about how hedonic valence of touch is processed at the cortical level. Here we investigated the electrophysiological correlates of affective tactile sensation during caressing of the right forearm with pleasant and unpleasant textile fabrics. We show dissociation between more physically driven differential brain responses to the different fabrics in early somatosensory cortex – the well-known mu-suppression (10-20 Hz - and a beta-band response (25-30 Hz in presumably higher-order somatosensory areas in the right-hemisphere that correlated well with the subjective valence of tactile caressing. Importantly, when using single trial classification techniques, beta-power significantly distinguished between pleasant and unpleasant stimulation on a single trial basis with high accuracy. Our results therefore suggest a dissociation of the sensory and affective aspects of touch in the somatosensory system and may provide features that may be used for single trial decoding of affective mental states from simple electroencephalographic measurements.

Tactile Aids

Directory of Open Access Journals (Sweden)

Mohtaramossadat Homayuni

1996-04-01

Full Text Available Tactile aids, which translate sound waves into vibrations that can be felt by the skin, have been used for decades by people with severe/profound hearing loss to enhance speech/language development and improve speechreading.The development of tactile aids dates from the efforts of Goults and his co-workers in the 1920s; Although The power supply was too voluminous and it was difficult to carry specially by children, it was too huge and heavy to be carried outside the laboratories and its application was restricted to the experimental usage. Nowadays great advances have been performed in producing this instrument and its numerous models is available in markets around the world.

Air and Bone Conduction Thresholds of Deaf and Normal Hearing Subjects before and during the Elimination of Cutaneous-Tactile Interference with Anesthesia. Final Report.

Science.gov (United States)

Nober, E. Harris

The study investigated whether low frequency air and bone thresholds elicited at high intensity levels from deaf children with a sensory-neural diagnosis reflect valid auditory sensitivity or are mediated through cutaneous-tactile receptors. Subjects were five totally deaf (mean age 17.0) yielding vibrotactile thresholds but with no air and bone…

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

Science.gov (United States)

2015-08-01

Similarly, tactile alerts can help manage and focus attention in a complex high-tempo multitasked environment. Figure 1, while simple, can serve to...tactile cueing on concurrent performance of military and robotics tasks in a simulated multitasking environment. Ergonomics. 2008;51(8):1137–1152...2007;78(3):338. Moorhead IR, Holmes S, Furnell S. Understanding multisensory integration for pilot spatial orientation. Farnborough (UK): QinetiQ

Association of Sensory Processing and Eating Problems in Children with Autism Spectrum Disorders

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Geneviève Nadon

2011-01-01

Full Text Available “Selective” or “picky eating” is a frequent problem in children with autism spectrum disorders (ASD. Many of these children do not treat sensory input, particularly olfactory, auditory, visual, and tactile information in the same manner as their typically developing peers of the same age. The purpose of this paper was to examine the relationship between problems of sensory processing and the number of eating problems in children with ASD. Of 95 children with ASD, 3 to 10 years of age, 65 percent showed a definite difference and 21 percent a probable difference in sensory processing on the total score of the Short Sensory Profile. These results were significantly related to an increase in the number of eating problems measured by the Eating Profile. These results could not be explained by age, sex, mental retardation, attention deficit disorder, or hyperactivity. Timely interventions focusing on the sensory components of eating must now be developed.

Rat model of cancer-induced bone pain: changes in nonnociceptive sensory neurons in vivo

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Yong Fang Zhu

2017-08-01

Conclusion:. After induction of the CIBP model, Aβ-fiber LTMs at >2 weeks but not <1 week had undergone changes in electrophysiological properties. Importantly, changes observed are consistent with observations in models of peripheral neuropathy. Thus, Aβ-fiber nonnociceptive primary sensory neurons might be involved in the peripheral sensitization and tumor-induced tactile hypersensitivity in CIBP.

Visual illusion of tool use recalibrates tactile perception

Science.gov (United States)

Miller, Luke E.; Longo, Matthew R.; Saygin, Ayse P.

2018-01-01

Brief use of a tool recalibrates multisensory representations of the user’s body, a phenomenon called tool embodiment. Despite two decades of research, little is known about its boundary conditions. It has been widely argued that embodiment requires active tool use, suggesting a critical role for somatosensory and motor feedback. The present study used a visual illusion to cast doubt on this view. We used a mirror-based setup to induce a visual experience of tool use with an arm that was in fact stationary. Following illusory tool use, tactile perception was recalibrated on this stationary arm, and with equal magnitude as physical use. Recalibration was not found following illusory passive tool holding, and could not be accounted for by sensory conflict or general interhemispheric plasticity. These results suggest visual tool-use signals play a critical role in driving tool embodiment. PMID:28196765

Exploration of the Effectiveness of Tactile Methods

Science.gov (United States)

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…

Comparison of LEP and QST and their contribution to standard sensory diagnostic assessment of spinal lesions: a pilot study.

Science.gov (United States)

Geber, Christian; Baumgärtner, Ulf; Fechir, Marcel; Vogt, Thomas; Birklein, Frank; Treede, Rolf-Detlef

2011-06-01

This study evaluates the additional use of laser-evoked potentials (LEP) and quantitative sensory testing (QST) in the sensory assessment of spinal lesions. Four consecutive patients with spinal lesions verified by MRI and clinical evidence for mild spinothalamic tract involvement were included. The electrophysiological workup [somatosensory evoked potentials (SEP) and LEP] was compared to QST. Electrophysiology and QST were reassessed after about 6 months. LEP detected impaired spinothalamic tract function in 7/8 examinations. QST pointed to spinothalamic tract lesions by loss of thermal function (3/8); most frequent positive sensory signs (3/8) were paradoxical heat sensations. LEP and QST results were concordant in 6/8 examinations. SEPs were abnormal in 2/8 examinations. Congruent results between SEP and both LEP and QST were obtained in 3/8 examinations. LEP detected more deficits than any single QST parameter or their combination but additional QST allows the detection of positive sensory signs. The diagnostic gain of SEP was limited.

A Tactile Carina Nebula

Science.gov (United States)

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!

Sensorial differences according to sex and ages.

Science.gov (United States)

da Silva, L A; Lin, S M; Teixeira, M J; de Siqueira, J T T; Jacob Filho, W; de Siqueira, S R D T

2014-04-01

To investigate age and sex differences in orofacial sensory detection. One hundred and twenty-six (126) healthy subjects were divided into five groups according to their ages. They were assessed with a quantitative sensory testing protocol for gustative, olfactory, thermal (cold/warm), mechanical (tactile/vibration/electric), and pain (deep/superficial) detection thresholds. The corneal reflex was also evaluated. Data were analyzed with the one-way ANOVA, chi-squared, Fisher's exact, Mann-Whitney, and Kruskal-Wallis tests. The groups of subjects over 61 years old had higher olfactory (P sweet P = 0.004, salty P = 0.007, sour P = 0.006), thermal (warm P sweet P = 0.020, salty P = 0.002, sour P < 0.001, and bitter P = 0.002), olfactory (P = 0.010), warm (P < 0.001) and deep (P < 0.001), and superficial pain (P = 0.008) detection thresholds than men, and men from all age groups had lower vibratory detection thresholds (P = 0.006) than women. High sensory detection thresholds were observed in subjects over the 6th decade of life, and women had a more accurate sensory perception than men. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Motor and sensory alalia: diagnostic difficulties

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M. Yu. Bobylova

2017-01-01

Full Text Available Alalia is a speech disorder that develops due to organic brain damage in children with normal hearing and intelligence during the first three year of life. Systemic speech underdevelopment in alalia is characterized by violations in the phonetic, phonemic, lexical, and grammatical structure. Patients with alalia can also have non-speech related impairments, including motor (impaired movement and coordination, sensory (impaired sensitivity and perception, and psychopathological disorders. There are three types of alalia: motor, sensory, and mixed. Children with motor alalia have expressive language disorders, speech praxis, poor speech fluency, impaired articulation, and other focal neurological symptoms; however, they understand speech directed to them. Patients with motor alalia are often left-handed. Regional slowing and epileptiform activity are often detected on their electroencephalogram.  Children with sensory alalia are characterized by poor speech understanding (despite normal hearing resulting in secondary underdevelopment of their own speech. These patients have problems with the analysis of sounds, including speech sounds (impaired speech gnosis, which prevents the development of association between the sound image and the object. Therefore, the child hears, but does not understand the speech directed at him/her (auditory agnosia. Differential diagnosis of alalia is challenging and may require several months of observation. It also implies the exclusion of hearing loss and mental disorders.

Implications of caries diagnostic strategies for clinical management decisions

DEFF Research Database (Denmark)

Baelum, Vibeke; Hintze, Hanne; Wenzel, Ann

2012-01-01

-specificity) were calculated for each diagnostic strategy. RESULTS: Visual-tactile examination provided a true-positive rate of 34.2% and a false-positive rate of 1.5% for the detection of a cavity. The combination of a visual-tactile and a radiographic examination using the lesion in dentin threshold......OBJECTIVES: In clinical practice, a visual-tactile caries examination is frequently supplemented by bitewing radiography. This study evaluated strategies for combining visual-tactile and radiographic caries detection methods and determined their implications for clinical management decisions...... and cavitated lesions while the radiographic examination determined lesion depth. Direct inspection of the surfaces following tooth separation for the presence of cavitated or noncavitated lesions was the validation method. The true-positive rate (i.e. the sensitivity) and the false-positive rate (i.e. 1...

Touch sensitive electrorheological fluid based tactile display

Science.gov (United States)

Liu, Yanju; Davidson, Rob; Taylor, Paul

2005-12-01

A tactile display is programmable device whose controlled surface is intended to be investigated by human touch. It has a great number of potential applications in the field of virtual reality and elsewhere. In this research, a 5 × 5 tactile display array including electrorheological (ER) fluid has been developed and investigated. Force responses of the tactile display array have been measured while a probe was moved across the upper surface. The purpose of this was to simulate the action of touch performed by human finger. Experimental results show that the sensed surface information could be controlled effectively by adjusting the voltage activation pattern imposed on the tactels. The performance of the tactile display is durable and repeatable. The touch sensitivity of this ER fluid based tactile display array has also been investigated in this research. The results show that it is possible to sense the touching force normal to the display's surface by monitoring the change of current passing through the ER fluid. These encouraging results are helpful for constructing a new type of tactile display based on ER fluid which can act as both sensor and actuator at the same time.

Sensory dissociation in chronic low back pain: Two case reports.

Science.gov (United States)

Adamczyk, Wacław M; Luedtke, Kerstin; Saulicz, Oskar; Saulicz, Edward

2018-08-01

Patients with chronic low back pain often report that they do not perceive their painful back accurately. Previous studies confirmed that sensory dissociation and/or discrepancy between perceived body image and actual size is one of the specific traits of patients with chronic pain. Current approaches for measuring sensory dissociation are limited to two-point-discrimination or rely on pain drawings not allowing for quantitative analysis. This case study reports the sensory dissociation of two cases with chronic low back pain using a recently published test (point-to-point-test (PTP)) and a newly developed test (two-point-estimation (TPE)). Both patients mislocalized tactile stimuli delivered to the painful location compared to non-painful locations (PTP test). In addition, both patients perceived their painful lumbar region differently from non-painful sites above and below and contralateral to the painful site. TPE data showed two distinct clinical patterns of sensory dissociation: one patient perceived the two-point distance in the painful area as expanded, while the other patient perceived it as shrunk. The latter pattern of sensory dissociation (i.e., pattern shrunk) is likely to respond to sensory training. Whether enlarged patterns of sensory dissociation are more resistant to treatment remains unknown but would explain the low effectiveness of previous studies using sensory training in chronic low back pain populations. Subgrouping patients according to their sensory discrimination pattern could contribute to the choice and effectiveness of the treatment approach.

Ambiguity in Tactile Apparent Motion Perception.

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Emanuela Liaci

Full Text Available In von Schiller's Stroboscopic Alternative Motion (SAM stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio ("AR", i.e. the relation between vertical and horizontal dot distances. Further, with equal horizontal and vertical dot distances (AR = 1 perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion.We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants' forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames.Increasing the tactile SAM's AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias.Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual

The functional upregulation of piriform cortex is associated with cross-modal plasticity in loss of whisker tactile inputs.

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Bing Ye

Full Text Available Cross-modal plasticity is characterized as the hypersensitivity of remaining modalities after a sensory function is lost in rodents, which ensures their awareness to environmental changes. Cellular and molecular mechanisms underlying cross-modal sensory plasticity remain unclear. We aim to study the role of different types of neurons in cross-modal plasticity.In addition to behavioral tasks in mice, whole-cell recordings at the excitatory and inhibitory neurons, and their two-photon imaging, were conducted in piriform cortex. We produced a mouse model of cross-modal sensory plasticity that olfactory function was upregulated by trimming whiskers to deprive their sensory inputs. In the meantime of olfactory hypersensitivity, pyramidal neurons and excitatory synapses were functionally upregulated, as well as GABAergic cells and inhibitory synapses were downregulated in piriform cortex from the mice of cross-modal sensory plasticity, compared with controls. A crosswire connection between barrel cortex and piriform cortex was established in cross-modal plasticity.An upregulation of pyramidal neurons and a downregulation of GABAergic neurons strengthen the activities of neuronal networks in piriform cortex, which may be responsible for olfactory hypersensitivity after a loss of whisker tactile input. This finding provides the clues for developing therapeutic strategies to promote sensory recovery and substitution.

Development of flexible array tactile sensors

DEFF Research Database (Denmark)

Drimus, Alin; Marian, Nicolae; Bilberg, Arne

2010-01-01

time data acquisition system scans all the cells and converts electrical resistance to tactile pressure maps. We validate that this information can be used to improve grasping and perform object recognition. Key words: piezoresistivity, tactile, sensor, pressure, robotics......In this paper we describe the development of an array tactile sensor for use in robotic grippers based on a flexible piezoresistive material. We start by comparing different cell structures in terms of output characteristics and we construct an array of cells in a row and columns layout. A real...

Body representation difficulties in children and adolescents with autism may be due to delayed development of visuo-tactile temporal binding

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Danielle Ropar

2018-01-01

Full Text Available Recent research suggests visuo-tactile binding is temporally extended in autism spectrum disorders (ASD, although it is not clear whether this specifically underlies altered body representation in this population. In the current study children and adolescents with ASD, and typically developing controls, placed their hand into mediated reality system (MIRAGE and saw two identical live video images of their own right hand. One image was in the proprioceptively correct location (veridical hand and the other was displaced to either side. While visuo-tactile feedback was applied via brushstroke to the participant’s (unseen right finger, they viewed one hand image receiving synchronous brushstrokes and the other receiving brushstrokes with a temporal delay (60, 180 and 300 ms. After brushing, both images disappeared from view and participants pointed to a target, with direction of movement indicating which hand was embodied. ASD participants, like younger mental aged-matched controls, showed reduced embodiment of the spatially incongruent, but temporally congruent, hand compared to chronologically age-matched controls at shorter temporal delays. This suggests development of visuo-tactile integration may be delayed in ASD. Findings are discussed in relation to atypical body representation in ASD and how this may contribute to social and sensory difficulties within this population. Keywords: Autism spectrum disorder, Temporal binding window, Visuo-tactile processing, Embodied action

The potential for developing a tactile communication system based on Blissymbolics.

Science.gov (United States)

Isaacson, Mick D; Lloyd, Lyle L

2015-02-01

To be useful for tactile communication, tactile stimuli need to be discriminable from each other. The objective of this study was to determine whether raised-line renderings of Blissymbols have the capacity for being developed into a tactile communication system as measured by their tactile discriminability. Tactile discrimination of Blissymbols was measured by performance on a task in which participants were asked to feel a target raised-line Blissymbol and then to find the target within an array containing the target and raised-line Blissymbol foils. The vast majority of tactile Blissymbols had tactile discrimination scores of 90% accuracy or better. Most raised-line Blissymbols can be tactilely discriminated from each other, indicating that they have the potential for being developed into a tactile communication system.

The critical events for motor-sensory temporal recalibration

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Derek Henry Arnold

2012-08-01

Full Text Available Determining if we, or another agent, were responsible for a sensory event can require an accurate sense of timing. Our sense of appropriate timing relationships must, however, be malleable as there is a variable delay between the physical timing of an event and when sensory signals concerning that event are encoded in the brain. One dramatic demonstration of such malleability involves having people repeatedly press a button thereby causing a beep. If a delay is inserted between button presses and beeps, when it is subsequently taken away beeps can seem to precede the button presses that caused them. For this to occur it is important that people feel they were responsible for instigating the beeps. In terms of their timing, as yet it is not clear what combination of events is important for motor-sensory temporal recalibration. Here, by introducing ballistic reaches of short or longer extent before a button press, we varied the delay between the intention to act and the sensory consequence of that action. This manipulation failed to modulate recalibration magnitude. By contrast, introducing a similarly lengthened delay between button presses and consequent beeps eliminated recalibration. Thus it would seem that the critical timing relationship for motor-sensory temporal recalibration is between tactile signals relating to the completion of an action and the subsequent auditory percept.

Tactile exploration of virtual objects for blind and sighted people: the role of beta 1 EEG band in sensory substitution and supramodal mental mapping

OpenAIRE

Campus, C.; Brayda, L.; De Carli, F.; Chellali, R.; Famà, F.; Bruzzo, C.; Lucagrossi, L.; Rodriguez, G.

2012-01-01

The neural correlates of exploration and cognitive mapping in blindness remain elusive. The role of visuo-spatial pathways in blind vs. sighted subjects is still under debate. In this preliminary study, we investigate, as a possible estimation of the activity in the visuo-spatial pathways, the EEG patterns of blind and blindfolded-sighted subjects during the active tactile construction of cognitive maps from virtual objects compared with rest and passive tactile stimulation. Ten blind and ten...

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

Science.gov (United States)

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.

An Embedded Sensory System for Worker Safety: Prototype Development and Evaluation.

Science.gov (United States)

Cho, Chunhee; Park, JeeWoong

2018-04-14

At a construction site, workers mainly rely on two senses, which are sight and sound, in order to perceive their physical surroundings. However, they are often hindered by the nature of most construction sites, which are usually dynamic, loud, and complicated. To overcome these challenges, this research explored a method using an embedded sensory system that might offer construction workers an artificial sensing ability to better perceive their surroundings. This study identified three parameters (i.e., intensity, signal length, and delay between consecutive pulses) needed for tactile-based signals for the construction workers to communicate quickly. We developed a prototype system based on these parameters, conducted experimental studies to quantify and validate the sensitivity of the parameters for quick communication, and analyzed test data to reveal what was added by this method in order to perceive information from the tactile signals. The findings disclosed that the parameters of tactile-based signals and their distinguishable ranges could be perceived in a short amount of time (i.e., a fraction of a second). Further experimentation demonstrated the capability of the identified unit signals combined with a signal mapping technique to effectively deliver simple information to individuals and offer an additional sense of awareness to the surroundings. The findings of this study could serve as a basis for future research in exploring advanced tactile-based messages to overcome challenges in environments for which communication is a struggle.

An Embedded Sensory System for Worker Safety: Prototype Development and Evaluation

Science.gov (United States)

Cho, Chunhee; Park, JeeWoong

2018-01-01

At a construction site, workers mainly rely on two senses, which are sight and sound, in order to perceive their physical surroundings. However, they are often hindered by the nature of most construction sites, which are usually dynamic, loud, and complicated. To overcome these challenges, this research explored a method using an embedded sensory system that might offer construction workers an artificial sensing ability to better perceive their surroundings. This study identified three parameters (i.e., intensity, signal length, and delay between consecutive pulses) needed for tactile-based signals for the construction workers to communicate quickly. We developed a prototype system based on these parameters, conducted experimental studies to quantify and validate the sensitivity of the parameters for quick communication, and analyzed test data to reveal what was added by this method in order to perceive information from the tactile signals. The findings disclosed that the parameters of tactile-based signals and their distinguishable ranges could be perceived in a short amount of time (i.e., a fraction of a second). Further experimentation demonstrated the capability of the identified unit signals combined with a signal mapping technique to effectively deliver simple information to individuals and offer an additional sense of awareness to the surroundings. The findings of this study could serve as a basis for future research in exploring advanced tactile-based messages to overcome challenges in environments for which communication is a struggle. PMID:29662008

Using hardware models to quantify sensory data acquisition across the rat vibrissal array.

Science.gov (United States)

Gopal, Venkatesh; Hartmann, Mitra J Z

2007-12-01

Our laboratory investigates how animals acquire sensory data to understand the neural computations that permit complex sensorimotor behaviors. We use the rat whisker system as a model to study active tactile sensing; our aim is to quantitatively describe the spatiotemporal structure of incoming sensory information to place constraints on subsequent neural encoding and processing. In the first part of this paper we describe the steps in the development of a hardware model (a 'sensobot') of the rat whisker array that can perform object feature extraction. We show how this model provides insights into the neurophysiology and behavior of the real animal. In the second part of this paper, we suggest that sensory data acquisition across the whisker array can be quantified using the complete derivative. We use the example of wall-following behavior to illustrate that computing the appropriate spatial gradients across a sensor array would enable an animal or mobile robot to predict the sensory data that will be acquired at the next time step.

Tactile and non-tactile sensory paradigms for fMRI and neurophysiologic studies in rodents

OpenAIRE

Sanganahalli, Basavaraju G.; Bailey, Christopher J.; Herman, Peter; Hyder, Fahmeed

2009-01-01

Functional magnetic resonance imaging (fMRI) has become a popular functional imaging tool for human studies. Future diagnostic use of fMRI depends, however, on a suitable neurophysiologic interpretation of the blood oxygenation level dependent (BOLD) signal change. This particular goal is best achieved in animal models primarily due to the invasive nature of other methods used and/or pharmacological agents applied to probe different nuances of neuronal (and glial) activity coupled to the BOLD...

Compliant Tactile Sensors

Science.gov (United States)

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.

The Design of Tactile Thematic Symbols

Science.gov (United States)

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…

Towards the Tactile Internet

DEFF Research Database (Denmark)

Szabó, Dávid; Gulyás, András; Fitzek, Frank

2015-01-01

5G communication networks enable the steering and control of Internet of Things and therefore require extreme low latency communication referred to as the tactile Internet. In this paper we show that the massive use of network coding throughout the network significantly improves latency and reduce...... the frequency of packet re-transmission, so an architecture built around network coding may be a feasible road towards realizing the tactile internet vision. Our contribution is threefold: (i) we show how network coding improves latency and reduces packet re-transmission with respect to other coding schemes...

Enhanced tactile encoding and memory recognition in congenital blindness.

Science.gov (United States)

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.

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

Science.gov (United States)

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

Sanshool on The Fingertip Interferes with Vibration Detection in a Rapidly-Adapting (RA Tactile Channel.

Directory of Open Access Journals (Sweden)

Scinob Kuroki

Full Text Available An Asian spice, Szechuan pepper (sanshool, is well known for the tingling sensation it induces on the mouth and on the lips. Electrophysiological studies have revealed that its active ingredient can induce firing of mechanoreceptor fibres that typically respond to mechanical vibration. Moreover, a human behavioral study has reported that the perceived frequency of sanshool-induced tingling matches with the preferred frequency range of the tactile rapidly adapting (RA channel, suggesting the contribution of sanshool-induced RA channel firing to its unique perceptual experience. However, since the RA channel may not be the only channel activated by sanshool, there could be a possibility that the sanshool tingling percept may be caused in whole or in part by other sensory channels. Here, by using a perceptual interference paradigm, we show that the sanshool-induced RA input indeed contributes to the human tactile processing. The absolute detection thresholds for vibrotactile input were measured with and without sanshool application on the fingertip. Sanshool significantly impaired detection of vibrations at 30 Hz (RA channel dominant frequency, but did not impair detection of higher frequency vibrations at 240 Hz (Pacinian-corpuscle (PC channel dominant frequency or lower frequency vibrations at 1 Hz (slowly adapting 1 (SA1 channel dominant frequency. These results show that the sanshool induces a peripheral RA channel activation that is relevant for tactile perception. This anomalous activation of RA channels may contribute to the unique tingling experience of sanshool.

Sensory perception in autism.

Science.gov (United States)

Robertson, Caroline E; Baron-Cohen, Simon

2017-11-01

Autism is a complex neurodevelopmental condition, and little is known about its neurobiology. Much of autism research has focused on the social, communication and cognitive difficulties associated with the condition. However, the recent revision of the diagnostic criteria for autism has brought another key domain of autistic experience into focus: sensory processing. Here, we review the properties of sensory processing in autism and discuss recent computational and neurobiological insights arising from attention to these behaviours. We argue that sensory traits have important implications for the development of animal and computational models of the condition. Finally, we consider how difficulties in sensory processing may relate to the other domains of behaviour that characterize autism.

Your place or mine: shared sensory experiences elicit a remapping of peripersonal space.

Science.gov (United States)

Maister, Lara; Cardini, Flavia; Zamariola, Giorgia; Serino, Andrea; Tsakiris, Manos

2015-04-01

Our perceptual systems integrate multisensory information about objects that are close to our bodies, which allow us to respond quickly and appropriately to potential threats, as well as act upon and manipulate useful tools. Intriguingly, the representation of this area close to our body, known as the multisensory 'peripersonal space' (PPS), can expand or contract during social interactions. However, it is not yet known how different social interactions can alter the representation of PPS. In particular, shared sensory experiences, such as those elicited by bodily illusions such as the enfacement illusion, can induce feelings of ownership over the other's body which has also been shown to increase the remapping of the other's sensory experiences onto our own bodies. The current study investigated whether such shared sensory experiences between two people induced by the enfacement illusion could alter the way PPS was represented, and whether this alteration could be best described as an expansion of one's own PPS towards the other or a remapping of the other's PPS onto one's own. An audio-tactile integration task allowed us to measure the extent of the PPS before and after a shared sensory experience with a confederate. Our results showed a clear increase in audio-tactile integration in the space close to the confederate's body after the shared experience. Importantly, this increase did not extend across the space between participant and confederate, as would be expected if the participant's PPS had expanded. Thus, the pattern of results is more consistent with a partial remapping of the confederate's PPS onto the participant's own PPS. These results have important consequences for our understanding of interpersonal space during different kinds of social interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diagnostic Accuracy of Quantitative Sensory Testing to Discriminate Inflammatory Toothache and Intraoral Neuropathic Pain.

Science.gov (United States)

Porporatti, André Luís; Costa, Yuri Martins; Stuginski-Barbosa, Juliana; Bonjardim, Leonardo Rigoldi; Duarte, Marco Antônio Hungaro; Conti, Paulo César Rodrigues

2015-10-01

A differential diagnosis between inflammatory toothache (IT) and intraoral neuropathic pain is challenging. The aim of this diagnostic study was to quantify somatosensory function of subjects with IT (acute pulpitis) and atypical odontalgia (AO, intraoral neuropathic pain) and healthy volunteers and to quantify how accurately quantitative sensory testing (QST) discriminates an IT or AO diagnosis. The sample consisted of 60 subjects equally divided (n = 20) into 3 groups: (1) IT, (2) AO, and (3) control. A sequence of 4 QST methods was performed over the dentoalveolar mucosa in the apical maxillar or mandibular area: mechanical detection threshold, pain detection threshold (PDT), dynamic mechanical allodynia, and temporal summation. One-way analysis of variance, Tukey post hoc analyses, and z score transformation were applied to the data. In addition, the receiver operating characteristic curve analysis, diagnostic accuracy, sensitivity, specificity, likelihood ratios, and diagnostic odds ratio of the QST methods were calculated (α = 5%). Somatosensory abnormalities were found for the AO group, which is consistent with a low detection threshold to touch and pain and the presence of mechanical allodynia. For the IT group, no somatosensory abnormality was observed when compared with the control group. The most accurate QST to discriminate the diagnostic differences between IT and healthy individuals is the PDT. The diagnostic differences between AO and healthy individuals and between IT and AO are best discriminated with the mechanical detection threshold, PDT, and dynamic mechanical allodynia. The proposed QST methods may aid in the differential diagnosis between IT and AO with strong accuracy and may be used as complementary diagnostic tests. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Tactile Stimulation and Consumer Response.

OpenAIRE

Hornik, Jacob

1992-01-01

Tactile behavior is a basic communication form as well as an expression of interpersonal involvement. This article presents three studies offering evidence for the positive role of casual interpersonal touch on consumer behavior. More specifically, it provides initial support for the view that tactile stimulation in various consumer behavior situations enhances the positive feeling for and evaluation of both the external stimuli and the touching source. Further, customers touched by a request...

Effects of the Brain-Derived Neurotrophic Factor Val66Met polymorphism and resting brain functional connectivity on individual differences in tactile cognitive performance in healthy young adults.

Science.gov (United States)

Yang, Xuejuan; Xu, Ziliang; Liu, Lin; Liu, Peng; Sun, Jinbo; Jin, Lingmin; Zhu, Yuanqiang; Fei, Ningbo; Qin, Wei

2017-07-28

Cognitive processes involve input from multiple sensory modalities and obvious differences in the level of cognitive function can be observed between individuals. Evidence to date understanding the biological basis of tactile cognitive variability, however, is limited compared with other forms of sensory cognition. Data from auditory and visual cognition research suggest that variations in both genetics and intrinsic brain function might contribute to individual differences in tactile cognitive performance. In the present study, by using the tactual performance test (TPT), a widely used neuropsychological assessment tool, we investigated the effects of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and resting-state brain functional connectivity (FC) on interindividual variability in TPT performance in healthy, young Chinese adults. Our results showed that the BDNF genotypes and resting-state FC had significant effects on the variability in TPT performance, together accounting for 32.5% and 19.1% of the variance on TPT total score and Memory subitem score respectively. Having fewer Met alleles, stronger anticorrelations between left posterior superior temporal gyrus and somatosensory areas (right postcentral gyrus and right parietal operculum cortex), and greater positive correlation between left parietal operculum cortex and left central opercular cortex, all correspond with better performance of TPT task. And FC between left parietal operculum cortex and left central opercular cortex might be a mediator of the relationship between BDNF genotypes and Memory subitem score. These data demonstrate a novel contribution of intrinsic brain function to tactile cognitive capacity, and further confirm the genetic basis of tactile cognition. Our findings might also explain the interindividual differences in cognitive ability observed in those who are blind and/or deaf from a new perspective. Copyright © 2017. Published by Elsevier Ltd.

Fluid-structure interaction-based biomechanical perception model for tactile sensing.

Directory of Open Access Journals (Sweden)

Zheng Wang

Full Text Available The reproduced tactile sensation of haptic interfaces usually selectively reproduces a certain object attribute, such as the object's material reflected by vibration and its surface shape by a pneumatic nozzle array. Tactile biomechanics investigates the relation between responses to an external load stimulus and tactile perception and guides the design of haptic interface devices via a tactile mechanism. Focusing on the pneumatic haptic interface, we established a fluid-structure interaction-based biomechanical model of responses to static and dynamic loads and conducted numerical simulation and experiments. This model provides a theoretical basis for designing haptic interfaces and reproducing tactile textures.

Maintenance of tactile short-term memory for locations is mediated by spatial attention.

Science.gov (United States)

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.

Sensory Robot Gripper

DEFF Research Database (Denmark)

Drimus, Alin

The project researches and proposes a tactile sensor system for equipping robotic grippers, thus giving them a sense of touch. We start by reviewing work that covers the building of tactile sensors and we focus on the flexible sensors with multiple sensing elements. As the piezoresistive, capacit......The project researches and proposes a tactile sensor system for equipping robotic grippers, thus giving them a sense of touch. We start by reviewing work that covers the building of tactile sensors and we focus on the flexible sensors with multiple sensing elements. As the piezoresistive......, such as establishing of contact, release of contact or slip. The proposed applications are just a few examples of the advantages of equipping robotic grippers with such a tactile sensor system, that is robust, fast, affordable, adaptable to any kind of gripper and has properties similar to the human sense of touch....... Based on experimental validation, we are confident that our proposed tactile sensor solution can be successfully employed in other application areas like reactive grasping, exploration of unknown objects, slip avoidance, dexterous manipulation or service robotics....

Sensory processing disorder: any of a nurse practitioner's business?

Science.gov (United States)

Byrne, Mary W

2009-06-01

Children who exhibit the confusing symptom patterns associated with sensory processing deficits are often seen first by primary care providers, including family and pediatric nurse practitioners (NPs). The purpose of this article is to alert NPs to the state of the science for these disorders and to the roles NPs could play in filling the knowledge gaps in assessment, treatment, education, and research. Literature searches using PubMed and MedLine databases and clinical practice observations. Sensory integration disorders have only begun to be defined during the past 35 years. They are not currently included in the DSM IV standard terminology, and are not yet substantively incorporated into most health disciplines' curricula or practice, including those of the NP. NPs are in a unique position to test hypothesized terminology for Sensory Processing Disorder (SPD) by contributing precise clinical descriptions of children who match as well as deviate from the criteria for three proposed diagnostic groups: Sensory Modulation Disorder (SMD), Sensory Discrimination Disorder (SDD), and Sensory-Based Motor Disorder (SBMD). Beyond the SPD diagnostic debate, for children with sensory deficit patterns the NP role can incorporate participating in interdisciplinary treatment plans, refining differential diagnoses, providing frontline referral and support for affected children and their families, and making both secondary prevention and critical causal research possible through validation of consistently accepted diagnostic criteria.

Magnetic Tactile Sensor for Braille Reading

KAUST Repository

Alfadhel, Ahmed

2016-04-27

We report a biomimetic magnetic tactile sensor for Braille characters reading. The sensor consists of magnetic nanocomposite artificial cilia implemented on magnetic micro sensors. The nanocomposite is produced from the highly elastic polydimethylsiloxane and iron nanowires that exhibit a permanent magnetic behavior. This design enables remote operation and does not require an additional magnetic field to magnetize the nanowires. The highly elastic nanocomposite is easy to pattern, corrosion resistant and thermally stable. The tactile sensors can detect vertical and shear forces, which allows recognizing small changes in surface texture, as in the case of Braille dots. The 6 dots of a braille cell are read from top to bottom with a tactile sensor array consisting of 4 elements and 1 mm long nanocomposite cilia.

Magnetic Tactile Sensor for Braille Reading

KAUST Repository

Alfadhel, Ahmed; Khan, Mohammed; Cardoso, Susana; Kosel, Jü rgen

2016-01-01

We report a biomimetic magnetic tactile sensor for Braille characters reading. The sensor consists of magnetic nanocomposite artificial cilia implemented on magnetic micro sensors. The nanocomposite is produced from the highly elastic polydimethylsiloxane and iron nanowires that exhibit a permanent magnetic behavior. This design enables remote operation and does not require an additional magnetic field to magnetize the nanowires. The highly elastic nanocomposite is easy to pattern, corrosion resistant and thermally stable. The tactile sensors can detect vertical and shear forces, which allows recognizing small changes in surface texture, as in the case of Braille dots. The 6 dots of a braille cell are read from top to bottom with a tactile sensor array consisting of 4 elements and 1 mm long nanocomposite cilia.

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

Science.gov (United States)

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.

Presentation of Various Tactile Sensations Using Micro-Needle Electrotactile Display.

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Mayuko Tezuka

Full Text Available Tactile displays provoke tactile sensations by artificially stimulating tactile receptors. While many types of tactile displays have been developed, electrotactile displays that exploit electric stimulation can be designed to be thin, light, flexible and thus, wearable. However, the high voltages required to stimulate tactile receptors and limited varieties of possible sensations pose problems. In our previous work, we developed an electrotactile display using a micro-needle electrode array that can drastically reduce the required voltage by penetrating through the high-impedance stratum corneum painlessly, but displaying various tactile sensations was still a challenge. In this work, we demonstrate presentation of tactile sensation of different roughness to the subjects, which is enabled by the arrangement of the electrodes; the needle electrodes are on the fingertip and the ground electrode is on the fingernail. With this arrangement, the display can stimulate the tactile receptors that are located not only in the shallow regions of the finger but also those in the deep regions. It was experimentally revealed that the required voltage was further reduced compared to previous devices and that the roughness presented by the display was controlled by the pulse frequency and the switching time, or the stimulation flow rate. The proposed electrotactile display is readily applicable as a new wearable haptic device for advanced information communication technology.

Sensory cortex underpinnings of traumatic brain injury deficits.

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Dasuni S Alwis

Full Text Available Traumatic brain injury (TBI can result in persistent sensorimotor and cognitive deficits including long-term altered sensory processing. The few animal models of sensory cortical processing effects of TBI have been limited to examination of effects immediately after TBI and only in some layers of cortex. We have now used the rat whisker tactile system and the cortex processing whisker-derived input to provide a highly detailed description of TBI-induced long-term changes in neuronal responses across the entire columnar network in primary sensory cortex. Brain injury (n=19 was induced using an impact acceleration method and sham controls received surgery only (n=15. Animals were tested in a range of sensorimotor behaviour tasks prior to and up to 6 weeks post-injury when there were still significant sensorimotor behaviour deficits. At 8-10 weeks post-trauma, in terminal experiments, extracellular recordings were obtained from barrel cortex neurons in response to whisker motion, including motion that mimicked whisker motion observed in awake animals undertaking different tasks. In cortex, there were lamina-specific neuronal response alterations that appeared to reflect local circuit changes. Hyper-excitation was found only in supragranular layers involved in intra-areal processing and long-range integration, and only for stimulation with complex, naturalistic whisker motion patterns and not for stimulation with simple trapezoidal whisker motion. Thus TBI induces long-term directional changes in integrative sensory cortical layers that depend on the complexity of the incoming sensory information. The nature of these changes allow predictions as to what types of sensory processes may be affected in TBI and contribute to post-trauma sensorimotor deficits.

Development of a Tactile Sensor Array

DEFF Research Database (Denmark)

Marian, Nicolae; Drimus, Alin; Bilberg, Arne

2010-01-01

Flexible grasping robots are needed for enabling automated, profitable and competitive production of small batch sizes including complex handling processes of often fragile objects. This development will create new conditions for value-adding activities in the production of the future world....... The paper describes the related research work we have developed for sensor design, exploration and control for a robot gripping system, in order to analyze normal forces applied on the tactile pixels for gripping force control and generate tactile images for gripping positioning and object recognition....... Section 1 gives an introduction of principles and technologies in tactile sensing for robot grippers. Section 2 presents the sensor cell (taxel) and array design and characterization. Section 3 introduces object recognition and shape analysis ideas showing a few preliminary examples, where geometrical...

Synaptic responses evoked by tactile stimuli in Purkinje cells in mouse cerebellar cortex Crus II in vivo.

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Chun-Ping Chu

Full Text Available Sensory stimuli evoke responses in cerebellar Purkinje cells (PCs via the mossy fiber-granule cell pathway. However, the properties of synaptic responses evoked by tactile stimulation in cerebellar PCs are unknown. The present study investigated the synaptic responses of PCs in response to an air-puff stimulation on the ipsilateral whisker pad in urethane-anesthetized mice.Thirty-three PCs were recorded from 48 urethane-anesthetized adult (6-8-week-old HA/ICR mice by somatic or dendritic patch-clamp recording and pharmacological methods. Tactile stimulation to the ipsilateral whisker pad was delivered by an air-puff through a 12-gauge stainless steel tube connected with a pressurized injection system. Under current-clamp conditions (I = 0, the air-puff stimulation evoked strong inhibitory postsynaptic potentials (IPSPs in the somata of PCs. Application of SR95531, a specific GABA(A receptor antagonist, blocked IPSPs and revealed stimulation-evoked simple spike firing. Under voltage-clamp conditions, tactile stimulation evoked a sequence of transient inward currents followed by strong outward currents in the somata and dendrites in PCs. Application of SR95531 blocked outward currents and revealed excitatory postsynaptic currents (EPSCs in somata and a temporal summation of parallel fiber EPSCs in PC dendrites. We also demonstrated that PCs respond to both the onset and offset of the air-puff stimulation.These findings indicated that tactile stimulation induced asynchronous parallel fiber excitatory inputs onto the dendrites of PCs, and failed to evoke strong EPSCs and spike firing in PCs, but induced the rapid activation of strong GABA(A receptor-mediated inhibitory postsynaptic currents in the somata and dendrites of PCs in the cerebellar cortex Crus II in urethane-anesthetized mice.

A Modified Tactile Brush Algorithm for Complex Touch Gestures

Energy Technology Data Exchange (ETDEWEB)

Ragan, Eric [Texas A& M University

2015-01-01

Several researchers have investigated phantom tactile sensation (i.e., the perception of a nonexistent actuator between two real actuators) and apparent tactile motion (i.e., the perception of a moving actuator due to time delays between onsets of multiple actuations). Prior work has focused primarily on determining appropriate Durations of Stimulation (DOS) and Stimulus Onset Asynchronies (SOA) for simple touch gestures, such as a single finger stroke. To expand upon this knowledge, we investigated complex touch gestures involving multiple, simultaneous points of contact, such as a whole hand touching the arm. To implement complex touch gestures, we modified the Tactile Brush algorithm to support rectangular areas of tactile stimulation.

Tactile cues can change movement: An example using tape to redistribute flexion from the lumbar spine to the hips and knees during lifting.

Science.gov (United States)

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.

Exploring mouthfeel in model wines: Sensory-to-instrumental approaches.

Science.gov (United States)

Laguna, Laura; Sarkar, Anwesha; Bryant, Michael G; Beadling, Andrew R; Bartolomé, Begoña; Victoria Moreno-Arribas, M

2017-12-01

Wine creates a group of oral-tactile stimulations not related to taste or aroma, such as astringency or fullness; better known as mouthfeel. During wine consumption, mouthfeel is affected by ethanol content, phenolic compounds and their interactions with the oral components. Mouthfeel arises through changes in the salivary film when wine is consumed. In order to understand the role of each wine component, eight different model wines with/without ethanol (8%), glycerol (10g/L) and commercial tannins (1g/L) were described using a trained panel. Descriptive analysis techniques were used to train the panel and measure the intensity of the mouthfeel attributes. Alongside, the suitability of different instrumental techniques (rheology, particle size, tribology and microstructure, using Transmission Electron Microscopy (TEM)) to measure wine mouthfeel sensation was investigated. Panelists discriminated samples based on their tactile-related components (ethanol, glycerol and tannins) at the levels found naturally in wine. Higher scores were found for all sensory attributes in the samples containing ethanol. Sensory astringency was associated mainly with the addition of tannins to the wine model and glycerol did not seem to play a discriminating role at the levels found in red wines. Visual viscosity was correlated with instrumental viscosity (R=0.815, p=0.014). Hydrodynamic diameter of saliva showed an increase in presence of tannins (almost 2.5-3-folds). However, presence of ethanol or glycerol decreased hydrodynamic diameter. These results were related with the sensory astringency and earthiness as well as with the formation of nano-complexes as observed by TEM. Rheologically, the most viscous samples were those containing glycerol or tannins. Tribology results showed that at a boundary lubrication regime, differences in traction coefficient lubrication were due by the presence of glycerol. However, no differences in traction coefficients were observed in presence

Effects of combining 2 weeks of passive sensory stimulation with active hand motor training in healthy adults.

Directory of Open Access Journals (Sweden)

Aija Marie Ladda

Full Text Available The gold standard to acquire motor skills is through intensive training and practicing. Recent studies have demonstrated that behavioral gains can also be acquired by mere exposure to repetitive sensory stimulation to drive the plasticity processes. Single application of repetitive electric stimulation (rES of the fingers has been shown to improve tactile perception in young adults as well as sensorimotor performance in healthy elderly individuals. The combination of repetitive motor training with a preceding rES has not been reported yet. In addition, the impact of such a training on somatosensory tactile and spatial sensitivity as well as on somatosensory cortical activation remains elusive. Therefore, we tested 15 right-handed participants who underwent repetitive electric stimulation of all finger tips of the left hand for 20 minutes prior to one hour of motor training of the left hand over the period of two weeks. Overall, participants substantially improved the motor performance of the left trained hand by 34%, but also showed a relevant transfer to the untrained right hand by 24%. Baseline ipsilateral activation fMRI-magnitude in BA 1 to sensory index finger stimulation predicted training outcome for somatosensory guided movements: those who showed higher ipsilateral activation were those who did profit less from training. Improvement of spatial tactile discrimination was positively associated with gains in pinch grip velocity. Overall, a combination of priming rES and repetitive motor training is capable to induce motor and somatosensory performance increase and representation changes in BA1 in healthy young subjects.

Optical Three-Axis Tactile Sensor for Robotic Fingers

OpenAIRE

Ohka, Masahiro; Takata, Jumpei; Kobayashi, Hiroaki; Suzuki, Hirofumi; Morisawa, Nobuyuki; Yussof, Hanafiah Bin

2008-01-01

A new three-axis tactile sensor to be mounted on multi-fingered hands is developed based on the principle of an optical waveguide-type tactile sensor comprised of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the present tactile sensor includes one columnar feeler and eight conical feelers. A three-axis force applied to the tip of the sensing element is detected by the contact areas of the conical feelers, which ma...

High Resolution Flexible Tactile Sensors

DEFF Research Database (Denmark)

Drimus, Alin; Bilberg, Arne

2011-01-01

both spatial distribution of pressure and dynamic events such as contact, release of contact and slip. Data acquisition and object recognition applications are described and it is proposed that such a sensor could be used in robotic grippers to improve object recognition, manipulation of objects......This paper describes the development of a tactile sensor for robotics inspired by the human sense of touch. It consists of two parts: a static tactile array sensor based on piezoresistive rubber and a dynamic sensor based on piezoelectric PVDF film. The combination of these two layers addresses...

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

Science.gov (United States)

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.

Primary or secondary tasks? Dual-task interference between cyclist hazard perception and cadence control using cross-modal sensory aids with rider assistance bike computers.

Science.gov (United States)

Yang, Chao-Yang; Wu, Cheng-Tse

2017-03-01

This research investigated the risks involved in bicycle riding while using various sensory modalities to deliver training information. To understand the risks associated with using bike computers, this study evaluated hazard perception performance through lab-based simulations of authentic riding conditions. Analysing hazard sensitivity (d') of signal detection theory, the rider's response time, and eye glances provided insights into the risks of using bike computers. In this study, 30 participants were tested with eight hazard perception tasks while they maintained a cadence of 60 ± 5 RPM and used bike computers with different sensory displays, namely visual, auditory, and tactile feedback signals. The results indicated that synchronously using different sense organs to receive cadence feedback significantly affects hazard perception performance; direct visual information leads to the worst rider distraction, with a mean sensitivity to hazards (d') of -1.03. For systems with multiple interacting sensory aids, auditory aids were found to result in the greatest reduction in sensitivity to hazards (d' mean = -0.57), whereas tactile sensory aids reduced the degree of rider distraction (d' mean = -0.23). Our work complements existing work in this domain by advancing the understanding of how to design devices that deliver information subtly, thereby preventing disruption of a rider's perception of road hazards. Copyright © 2016 Elsevier Ltd. All rights reserved.

Integration of auditory and tactile inputs in musical meter perception.

Science.gov (United States)

Huang, Juan; Gamble, Darik; Sarnlertsophon, Kristine; Wang, Xiaoqin; Hsiao, Steven

2013-01-01

Musicians often say that they not only hear but also "feel" music. To explore the contribution of tactile information to "feeling" music, we investigated the degree that auditory and tactile inputs are integrated in humans performing a musical meter-recognition task. Subjects discriminated between two types of sequences, "duple" (march-like rhythms) and "triple" (waltz-like rhythms), presented in three conditions: (1) unimodal inputs (auditory or tactile alone); (2) various combinations of bimodal inputs, where sequences were distributed between the auditory and tactile channels such that a single channel did not produce coherent meter percepts; and (3) bimodal inputs where the two channels contained congruent or incongruent meter cues. We first show that meter is perceived similarly well (70-85 %) when tactile or auditory cues are presented alone. We next show in the bimodal experiments that auditory and tactile cues are integrated to produce coherent meter percepts. Performance is high (70-90 %) when all of the metrically important notes are assigned to one channel and is reduced to 60 % when half of these notes are assigned to one channel. When the important notes are presented simultaneously to both channels, congruent cues enhance meter recognition (90 %). Performance dropped dramatically when subjects were presented with incongruent auditory cues (10 %), as opposed to incongruent tactile cues (60 %), demonstrating that auditory input dominates meter perception. These observations support the notion that meter perception is a cross-modal percept with tactile inputs underlying the perception of "feeling" music.

Review of Recent Inkjet-Printed Capacitive Tactile Sensors

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Ahmed Salim

2017-11-01

Full Text Available 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.

Testing Tactile Masking between the Forearms.

Science.gov (United States)

D'Amour, Sarah; Harris, Laurence R

2016-02-10

Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, usually using stimuli that are close together to reveal local interactions. Masking effects have also been demonstrated in which a tactile stimulus alters the perception of a touch at a distant location. Such effects can provide insight into how components of the body's representations in the brain may be linked. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at corresponding contralateral locations. To explore the matching of corresponding points across the body, we can measure the spatial tuning and effect of posture on contralateral masking. Careful controls are required to rule out direct effects of the remote stimulus, for example by mechanical transmission, and also attention effects in which thresholds may be altered by the participant's attention being drawn away from the stimulus of interest. The use of this technique is beneficial as a behavioural measure for exploring which parts of the body are functionally connected and whether the two sides of the body interact in a somatotopic representation. This manuscript describes a behavioural protocol that can be used for studying contralateral tactile masking.

Unmyelinated tactile cutaneous nerves signal erotic sensations.

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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

Hybrid-Actuated Finger Prosthesis with Tactile Sensing

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Cheng Yee Low

2013-10-01

Full Text Available Finger prostheses are devices developed to emulate the functionality of natural human fingers. On top of their aesthetic appearance in terms of shape, size and colour, such biomimetic devices require a high level of dexterity. They must be capable of gripping an object, and even manipulating it in the hand. This paper presents a biomimetic robotic finger actuated by a hybrid mechanism and integrated with a tactile sensor. The hybrid actuation mechanism comprises a DC micromotor and a Shape Memory Alloy (SMA wire. A customized test rig has been developed to measure the force and stroke produced by the SMA wire. In parallel with the actuator development, experimental investigations have been conducted on Quantum Tunnelling Composite (QTC and Pressure Conductive Rubber (PCR towards the development of a tactile sensor for the finger. The viability of using these materials for tactile sensing has been determined. Such a hybrid actuation approach aided with tactile sensing capability enables a finger design as an integral part of a prosthetic hand for applications up to the transradial amputation level.

Acquisition of a bodily-tactile language as first language

DEFF Research Database (Denmark)

Ask Larsen, Flemming

2013-01-01

Language acquisition in the bodily-tactile modality is difficult to understand, describe, and support. This chapter advocates a reinterpretation of the gestural and idiosyncratic bodily-tactile communication of people with congenital deafblindness (CDB) in terms of early language acquisition...... towards Tactile Sign Language (TSL). The access to participation in complex TSL culture is crucial for language acquisition. We already know how to transfer the patterns of social interaction into the bodily-tactile modality. This is the fundation on which to build actual linguistic participation. TSL...... as a first language is presently a theoretic possibility. We need more research on how to accommodate TSL to language Development and on how to fit TSL into participation in complex cultural activities....

Attention Modulates Visual-Tactile Interaction in Spatial Pattern Matching

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Göschl, Florian; Engel, Andreas K.; Friese, Uwe

2014-01-01

Factors influencing crossmodal interactions are manifold and operate in a stimulus-driven, bottom-up fashion, as well as via top-down control. Here, we evaluate the interplay of stimulus congruence and attention in a visual-tactile task. To this end, we used a matching paradigm requiring the identification of spatial patterns that were concurrently presented visually on a computer screen and haptically to the fingertips by means of a Braille stimulator. Stimulation in our paradigm was always bimodal with only the allocation of attention being manipulated between conditions. In separate blocks of the experiment, participants were instructed to (a) focus on a single modality to detect a specific target pattern, (b) pay attention to both modalities to detect a specific target pattern, or (c) to explicitly evaluate if the patterns in both modalities were congruent or not. For visual as well as tactile targets, congruent stimulus pairs led to quicker and more accurate detection compared to incongruent stimulation. This congruence facilitation effect was more prominent under divided attention. Incongruent stimulation led to behavioral decrements under divided attention as compared to selectively attending a single sensory channel. Additionally, when participants were asked to evaluate congruence explicitly, congruent stimulation was associated with better performance than incongruent stimulation. Our results extend previous findings from audiovisual studies, showing that stimulus congruence also resulted in behavioral improvements in visuotactile pattern matching. The interplay of stimulus processing and attentional control seems to be organized in a highly flexible fashion, with the integration of signals depending on both bottom-up and top-down factors, rather than occurring in an ‘all-or-nothing’ manner. PMID:25203102

Attention modulates visual-tactile interaction in spatial pattern matching.

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Florian Göschl

Full Text Available Factors influencing crossmodal interactions are manifold and operate in a stimulus-driven, bottom-up fashion, as well as via top-down control. Here, we evaluate the interplay of stimulus congruence and attention in a visual-tactile task. To this end, we used a matching paradigm requiring the identification of spatial patterns that were concurrently presented visually on a computer screen and haptically to the fingertips by means of a Braille stimulator. Stimulation in our paradigm was always bimodal with only the allocation of attention being manipulated between conditions. In separate blocks of the experiment, participants were instructed to (a focus on a single modality to detect a specific target pattern, (b pay attention to both modalities to detect a specific target pattern, or (c to explicitly evaluate if the patterns in both modalities were congruent or not. For visual as well as tactile targets, congruent stimulus pairs led to quicker and more accurate detection compared to incongruent stimulation. This congruence facilitation effect was more prominent under divided attention. Incongruent stimulation led to behavioral decrements under divided attention as compared to selectively attending a single sensory channel. Additionally, when participants were asked to evaluate congruence explicitly, congruent stimulation was associated with better performance than incongruent stimulation. Our results extend previous findings from audiovisual studies, showing that stimulus congruence also resulted in behavioral improvements in visuotactile pattern matching. The interplay of stimulus processing and attentional control seems to be organized in a highly flexible fashion, with the integration of signals depending on both bottom-up and top-down factors, rather than occurring in an 'all-or-nothing' manner.

A Case Study of Tactile Language and its Possible Structure

DEFF Research Database (Denmark)

Dammeyer, Jesper Herup; Nielsen, Anja; Strøm, Emilie

2015-01-01

Few published research papers concern the study of communication and language development among children with congenital deafblindness. The aim of this study is to explore and discuss linguistic features of what may be considered as tactile languages. By analysing one pilot video observation of a...... on direction, speed and acceleration of movements, pressure, and body position. It is discussed how tactile languages, if they exist, can be studied from its unique bodily-tactile nature and not as a modification of visual sign languages.......Few published research papers concern the study of communication and language development among children with congenital deafblindness. The aim of this study is to explore and discuss linguistic features of what may be considered as tactile languages. By analysing one pilot video observation...... of a five year old congenital deafblind child communicating with his mother about a slide experience tactile linguistic features of phonology, morphology, semantics and syntax were explored. The linguistic features of tactile language were found to involve a potential unique and complex structure based...

Sensory augmentation for the blind

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Silke Manuela Kärcher

2012-03-01

Full Text Available Enacted theories of consciousness conjecture that perception and cognition arise from an active experience of the regular relations that are tying together the sensory stimulation of different modalities and associated motor actions. Previous experiments investigated this concept by employing the technique of sensory substitution. Building on these studies, here we test a set of hypotheses derived from this framework and investigate the utility of sensory augmentation in handicapped people. We provide a late blind subject with a new set of sensorimotor laws: A vibro-tactile belt continually signals the direction of magnetic north. The subject completed a set of behavioral tests before and after an extended training period. The tests were complemented by questionnaires and interviews. This newly supplied information improved performance on different time scales. In a pointing task we demonstrate an instant improvement of performance based on the signal provided by the device. Furthermore, the signal was helpful in relevant daily tasks, often complicated for the blind, such as keeping a direction over longer distances or taking shortcuts in familiar environments. A homing task with an additional attentional load demonstrated a significant improvement after training. The subject found the directional information highly expedient for the adjustment of his inner maps of familiar environments and describes an increase in his feeling of security when exploring unfamiliar environments with the belt. The results give evidence for a firm integration of the newly supplied signals into the behavior of this late blind subject with better navigational performance and more courageous behavior in unfamiliar environments. Most importantly, the complementary information provided by the belt lead to a positive emotional impact with enhanced feeling of security. This experimental approach demonstrates the potential of sensory augmentation devices for the help of

Displaying Sensed Tactile Cues with a Fingertip Haptic Device.

Science.gov (United States)

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 Experience Shapes Prey-Capture Behavior in Etruscan Shrews

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Michael eBrecht

2012-06-01

Full Text Available A crucial role of tactile experience for the maturation of neural response properties in the somatosensory system is well established, but little is known about the role of tactile experience in the development of tactile behaviors. Here we study how tactile experience affects prey capture behavior in Etruscan shrews, Suncus etruscus. Prey capture in adult shrews is a high-speed behavior that relies on precise attacks guided by tactile Gestalt cues. We studied the role of tactile experience by three different approaches. First, we analyzed the hunting skills of young shrews right after weaning. We found that prey capture in young animals is most but not all aspects similar to that of adults. Second we performed whisker trimming for three to four weeks after birth. Such deprivation resulted in a lasting disruption of prey capture even after whisker re-growth: attacks lacked precise targeting and had a lower success rate. Third, we presented adult shrews with an entirely novel prey species, the giant cockroach. The shape of this roach is very different from the shrew’s normal (cricket prey and the thorax – the preferred point of attack in crickets – is protected a heavy cuticle. Initially shrews attacked giant roaches the same way they attack crickets and targeted the thoracic region. With progressive experience, however, shrews adopted a new attack strategy targeting legs and underside of the roaches while avoiding other body parts. Speed and efficiency of attacks improved. These data suggest that tactile experience shapes prey capture behavior.

Tactile Data Entry System

Science.gov (United States)

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 Studio, artigianato digitale al servizio dell’accessibilità

OpenAIRE

Riccardo Leone; Philippe Moreau

2017-01-01

Tactile Studio is a design agency for universal design in arts and culture. Tactile experiences are essential for people with visual impairm ents and gr eatly assist many people with cognitive disabilities. Tactile experiences should be included in every exhibition. Children, older adults, people with language diff iculties or fr om diff erent cultural backgr ounds..To name an audience who will not benefit fr om these designs is impossible. Pioneers in France, the nation's top museums have en...

Synesthesia, sensory-motor contingency, and semantic emulation: how swimming style-color synesthesia challenges the traditional view of synesthesia.

Science.gov (United States)

Mroczko-Wąsowicz, Aleksandra; Werning, Markus

2012-01-01

Synesthesia is traditionally regarded as a phenomenon in which an additional non-standard phenomenal experience occurs consistently in response to ordinary stimulation applied to the same or another modality. Recent studies suggest an important role of semantic representations in the induction of synesthesia. In the present proposal we try to link the empirically grounded theory of sensory-motor contingency and mirror system based embodied simulation/emulation to newly discovered cases of swimming style-color synesthesia. In the latter color experiences are evoked only by showing the synesthetes a picture of a swimming person or asking them to think about a given swimming style. Neural mechanisms of mirror systems seem to be involved here. It has been shown that for mirror-sensory synesthesia, such as mirror-touch or mirror-pain synesthesia (when visually presented tactile or noxious stimulation of others results in the projection of the tactile or pain experience onto oneself), concurrent experiences are caused by overactivity in the mirror neuron system responding to the specific observation. The comparison of different forms of synesthesia has the potential of challenging conventional thinking on this phenomenon and providing a more general, sensory-motor account of synesthesia encompassing cases driven by semantic or emulational rather than pure sensory or motor representations. Such an interpretation could include top-down associations, questioning the explanation in terms of hard-wired structural connectivity. In the paper the hypothesis is developed that the wide-ranging phenomenon of synesthesia might result from a process of hyperbinding between "too many" semantic attribute domains. This hypothesis is supplemented by some suggestions for an underlying neural mechanism.

Psychophysical sensory examination in individuals with a history of methylmercury exposure

International Nuclear Information System (INIS)

Takaoka, Shigeru; Fujino, Tadashi; Sekikawa, Tomoko; Miyaoka, Tetsu

2004-01-01

Paresthesias are the first symptom that people report following toxic doses of methylmercury. The authors conducted a psychophysical study of tactile sensation to evaluate the somatosensory abilities of subjects living in a methylmercury-polluted area around Minamata City, Japan. The authors examined control subjects and methylmercury-exposed subjects with and without numbness. A history of methylmercury exposure was taken and a neurological examination performed. Aluminum-oxide abrasive papers were used as stimuli in a psychophysical sensory examination of fine-surface-texture discrimination. Difference thresholds from 3 μm were calculated by the two-alternative, forced-choice technique. Difference thresholds in control subjects were also calculated for comparison. The difference threshold was 6.3 μm in exposed subjects with sensory symptoms, 4.9 μm in exposed subjects without sensory symptoms, and 2.7 μm in control subjects. Acuity of fine-surface-texture discrimination was disturbed not only in subjects with clinical complaints of hand numbness, but also in subjects without hand numbness who lived in the district where methylmercury exposure occurred. Sensory testing using a psychophysical test of fine-surface-texture discrimination in this population suggests that the number of individuals affected by methylmercury exposure in the polluted area was greater than previously reported

A Distributed Tactile Sensor for Intuitive Human-Robot Interfacing

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Andrea Cirillo

2017-01-01

Full Text Available Safety of human-robot physical interaction is enabled not only by suitable robot control strategies but also by suitable sensing technologies. For example, if distributed tactile sensors were available on the robot, they could be used not only to detect unintentional collisions, but also as human-machine interface by enabling a new mode of social interaction with the machine. Starting from their previous works, the authors developed a conformable distributed tactile sensor that can be easily conformed to the different parts of the robot body. Its ability to estimate contact force components and to provide a tactile map with an accurate spatial resolution enables the robot to handle both unintentional collisions in safe human-robot collaboration tasks and intentional touches where the sensor is used as human-machine interface. In this paper, the authors present the characterization of the proposed tactile sensor and they show how it can be also exploited to recognize haptic tactile gestures, by tailoring recognition algorithms, well known in the image processing field, to the case of tactile images. In particular, a set of haptic gestures has been defined to test three recognition algorithms on a group of 20 users. The paper demonstrates how the same sensor originally designed to manage unintentional collisions can be successfully used also as human-machine interface.

A magnetoencephalography study of multi-modal processing of pain anticipation in primary sensory cortices.

Science.gov (United States)

Gopalakrishnan, R; Burgess, R C; Plow, E B; Floden, D P; Machado, A G

2015-09-24

Pain anticipation plays a critical role in pain chronification and results in disability due to pain avoidance. It is important to understand how different sensory modalities (auditory, visual or tactile) may influence pain anticipation as different strategies could be applied to mitigate anticipatory phenomena and chronification. In this study, using a countdown paradigm, we evaluated with magnetoencephalography the neural networks associated with pain anticipation elicited by different sensory modalities in normal volunteers. When encountered with well-established cues that signaled pain, visual and somatosensory cortices engaged the pain neuromatrix areas early during the countdown process, whereas the auditory cortex displayed delayed processing. In addition, during pain anticipation, the visual cortex displayed independent processing capabilities after learning the contextual meaning of cues from associative and limbic areas. Interestingly, cross-modal activation was also evident and strong when visual and tactile cues signaled upcoming pain. Dorsolateral prefrontal cortex and mid-cingulate cortex showed significant activity during pain anticipation regardless of modality. Our results show pain anticipation is processed with great time efficiency by a highly specialized and hierarchical network. The highest degree of higher-order processing is modulated by context (pain) rather than content (modality) and rests within the associative limbic regions, corroborating their intrinsic role in chronification. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Effect of Means of Problem-Oriented Physical Rehabilitation on Pain and Tactile Sensitivity and Pain Syndrome Intensity in Women with Post-Mastectomy Syndrome

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Т. Є. Одинець

2015-03-01

Full Text Available The objective of the paper is to determine the effectiveness of problem-oriented physical rehabilitation of women with post-mastectomy syndrome in terms of normalization of their sensitivity and lessening of the pain syndrome. Materials and methods. The paper provides a review of the related literary sources and empirical data analyzed and summarized, offers definitions of pain by the Visual Analogue Scale, McGill Pain Questionnaire and the Verbal Rating Scale, evaluates tactile and pain sensitivity, and uses the methods of mathematical statistics. The participants in the study were 50 women with diagnosed with the post-mastectomy syndrome and at the stage of residential treatment. Results: The developed problem-oriented physical rehabilitation experimentally proved effective by showing improvements in tactile and pain sensitivity, and pain lessening by the sensory, affective and rating scales in women with post-mastectomy syndrome at the stage of residential treatment.

Tactile Radar: experimenting a computer game with visually disabled.

Science.gov (United States)

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.

Degree of skin denervation and its correlation to objective thermal sensory test in leprosy patients.

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Ismael Alves Rodrigues Júnior

Full Text Available BACKGROUND: Leprosy is an infectious disease affecting skin and peripheral nerves resulting in increased morbidity and physical deformities. Early diagnosis provides opportune treatment and reduces its complications, relying fundamentally on the demonstration of impaired sensation in suggestive cutaneous lesions. The loss of tactile sensitivity in the lesions is preceded by the loss of thermal sensitivity, stressing the importance of the thermal test in the suspicious lesions approach. The gold-standard method for the assessment of thermal sensitivity is the quantitative sensory test (QST. Morphological study may be an alternative approach to access the thin nerve fibers responsible for thermal sensitivity transduction. The few studies reported in leprosy patients pointed out a rarefaction of thin dermo-epidermal fibers in lesions, but used semi-quantitative evaluation methods. METHODOLOGY/PRINCIPAL FINDINGS: This work aimed to study the correlation between the degree of thermal sensitivity impairment measured by QST and the degree of denervation in leprosy skin lesions, evaluated by immunohistochemistry anti-PGP 9.5 and morphometry. Twenty-two patients were included. There were significant differences in skin thermal thresholds among lesions and contralateral skin (cold, warm, cold induced pain and heat induced pain. The mean reduction in the density of intraepidermal and subepidermal fibers in lesions was 79.5% (SD = 19.6 and 80.8% (SD = 24.9, respectively. CONCLUSIONS/SIGNIFICANCE: We observed a good correlation between intraepidermal and subepidermal fibers deficit, but no correlation between these variables and those accounting for the degree of impairment in thermal thresholds, since the thin fibers rarefaction was homogeneously intense in all patients, regardless of the degree of sensory deficit. We believe that the homogeneously intense denervation in leprosy lesions should be objective of further investigations focused on its

Sensory modulation disorder symptoms in anorexia nervosa and bulimia nervosa: A pilot study.

Science.gov (United States)

Brand-Gothelf, Ayelet; Parush, Shula; Eitan, Yehudith; Admoni, Shai; Gur, Eitan; Stein, Daniel

2016-01-01

Individuals with anorexia nervosa (AN) and bulimia nervosa (BN) may exhibit reduced ability to modulate sensory, physiological, and affective responses. The aim of the present study is to assess sensory modulation disorder (SMD) symptoms in patients with AN and BN. We assessed female adolescent and young adult inpatients with restrictive type anorexia nervosa (AN-R; n = 20) and BN (n = 20) evaluated in the acute stage of their illness, and 27 female controls. Another group of 20 inpatients with AN-R was assessed on admission and discharge, upon achieving their required weight. Participants completed standardized questionnaires assessing the severity of their eating disorder (ED) and the sensory responsiveness questionnaire (SRQ). Inpatients with AN-R demonstrated elevated overall sensory over-responsiveness as well as elevated scores on the taste/gustatory, vestibular/kinesthetic and somatosensory/tactile SRQ modalities compared with patients with BN and controls. Significant correlations between the severity of sensory over-responsiveness and ED-related symptomatology were found in acutely-ill patients with AN-R and to a lesser extent, following weight restoration. Elevated sensory over-responsiveness was retained in weight-restored inpatients with AN-R. Inpatients with BN demonstrated greater sensory under-responsiveness in the intensity subscale of the SRQ, but not in the frequency and combined SRQ dimensions. Female inpatients with AN-R exhibited sensory over-responsiveness both in the acute stage of their illness and following weight restoration, suggesting that sensory over-responsiveness may represent a trait related to the illness itself above and beyond the influence of malnutrition. The finding for sensory under-responsiveness in BN is less consistent. © 2015 Wiley Periodicals, Inc.

Role of PAF receptor in proinflammatory cytokine expression in the dorsal root ganglion and tactile allodynia in a rodent model of neuropathic pain.

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Shigeo Hasegawa

Full Text Available BACKGROUND: Neuropathic pain is a highly debilitating chronic pain following damage to peripheral sensory neurons and is often resistant to all treatments currently available, including opioids. We have previously shown that peripheral nerve injury induces activation of cytosolic phospholipase A(2 (cPLA(2 in injured dorsal root ganglion (DRG neurons that contribute to tactile allodynia, a hallmark of neuropathic pain. However, lipid mediators downstream of cPLA(2 activation to produce tactile allodynia remain to be determined. PRINCIPAL FINDINGS: Here we provide evidence that platelet-activating factor (PAF is a potential candidate. Pharmacological blockade of PAF receptors (PAFRs reduced the development and expression of tactile allodynia following nerve injury. The expression of PAFR mRNA was increased in the DRG ipsilateral to nerve injury, which was seen mainly in macrophages. Furthermore, mice lacking PAFRs showed a reduction of nerve injury-induced tactile allodynia and, interestingly, a marked suppression of upregulation of tumor necrosis factor alpha (TNFalpha and interleukin-1beta (IL-1beta expression in the injured DRG, crucial proinflammatory cytokines involved in pain hypersensitivity. Conversely, a single injection of PAF near the DRG of naïve rats caused a decrease in the paw withdrawal threshold to mechanical stimulation in a dose-dependent manner and an increase in the expression of mRNAs for TNFalpha and IL-1beta, both of which were inhibited by pretreatment with a PAFR antagonist. CONCLUSIONS: Our results indicate that the PAF/PAFR system has an important role in production of TNFalpha and IL-1beta in the DRG and tactile allodynia following peripheral nerve injury and suggest that blocking PAFRs may be a viable therapeutic strategy for treating neuropathic pain.

TACTILE STIMULATION EVOKES LONG-LASTING POTENTIATION OF PURKINJE CELL DISCHARGE IN VIVO

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Ramakrishnan eKanchipuram

2016-02-01

Full Text Available In the cerebellar network, a precise relationship between plasticity and neuronal discharge has been predicted. However, the potential generation of persistent changes in PC spike discharge as a consequence of plasticity following natural stimulation patterns has not been clearly determined. Here we show that facial tactile stimuli organized in theta-patterns can induce stereotyped NMDA and GABA-A receptor-dependent changes in Purkinje cell (PCs and molecular layer interneuron (MLIs firing: invariably, all PCs showed a long-lasting increase (spike-related potentiation or SR-P and MLIs a long-lasting decrease (spike-related suppression or SR-S in baseline activity and spike response probability. These observations suggests that natural sensory stimulation engages multiple long-term plastic changes that are distributed along the mossy fiber – parallel fiber pathway and operate synergistically to potentiate spike generation in PCs. In contrast, theta-pattern electrical stimulation of PFs indistinctly induced SR-P and SR-S both in PCs and MLIs, suggesting that natural sensory stimulation preordinates plasticity upstream of the PF-PC synapse. All these effects occurred in the absence of complex spike changes, supporting the theoretical prediction that Purkinje cell activity is potentiated when the mossy fiber - parallel fiber system is activated in the absence of conjunctive climbing fiber activity.

Stable phase-shift despite quasi-rhythmic movements: a CPG-driven dynamic model of active tactile exploration in an insect

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Nalin eHarischandra

2015-08-01

Full Text Available An essential component of autonomous and flexible behaviour in animals is active exploration of the environment, allowing for perception-guided planning and control of actions. An important sensory system involved is active touch. Here, we introduce a general modelling framework of Central Pattern Generators (CPGs for movement generation in active tactile exploration behaviour. The CPG consists of two network levels: (i phase-coupled Hopf oscillators for rhythm generation, and (ii pattern formation networks for capturing the frequency and phase characteristics of individual joint oscillations. The model captured the natural, quasi-rhythmic joint kinematics as observed in coordinated antennal movements of walking stick insects. Moreover, it successfully produced tactile exploration behaviour on a three-dimensional skeletal model of the insect antennal system with physically realistic parameters. The effect of proprioceptor ablations could be simulated by changing the amplitude and offset parameters of the joint oscillators, only. As in the animal, the movement of both antennal joints was coupled with a stable phase difference, despite the quasi-rhythmicity of the joint angle time courses. We found that the phase-lead of the distal scape-pedicel joint relative to the proximal head-scape joint was essential for producing the natural tactile exploration behaviour and, thus, for tactile efficiency. For realistic movement patterns, the phase-lead could vary within a limited range of 10 to 30 degrees only. Tests with artificial movement patterns strongly suggest that this phase sensitivity is not a matter of the frequency composition of the natural movement pattern. Based on our modelling results, we propose that a constant phase difference is coded into the CPG of the antennal motor system and that proprioceptors are acting locally to regulate the joint movement amplitude.

Magnetic resonance imaging-compatible tactile sensing device based on a piezoelectric array.

Science.gov (United States)

Hamed, Abbi; Masamune, Ken; Tse, Zion Tsz Ho; Lamperth, Michael; Dohi, Takeyoshi

2012-07-01

Minimally invasive surgery is a widely used medical technique, one of the drawbacks of which is the loss of direct sense of touch during the operation. Palpation is the use of fingertips to explore and make fast assessments of tissue morphology. Although technologies are developed to equip minimally invasive surgery tools with haptic feedback capabilities, the majority focus on tissue stiffness profiling and tool-tissue interaction force measurement. For greatly increased diagnostic capability, a magnetic resonance imaging-compatible tactile sensor design is proposed, which allows minimally invasive surgery to be performed under image guidance, combining the strong capability of magnetic resonance imaging soft tissue and intuitive palpation. The sensing unit is based on a piezoelectric sensor methodology, which conforms to the stringent mechanical and electrical design requirements imposed by the magnetic resonance environment The sensor mechanical design and the device integration to a 0.2 Tesla open magnetic resonance imaging scanner are described, together with the device's magnetic resonance compatibility testing. Its design limitations and potential future improvements are also discussed. A tactile sensing unit based on a piezoelectric sensor principle is proposed, which is designed for magnetic resonance imaging guided interventions.

Tactile Toe Agnosia and Percept of a "Missing Toe" in Healthy Humans.

Science.gov (United States)

Cicmil, Nela; Meyer, Achim P; Stein, John F

2016-03-01

A disturbance of body representation is central to many neurological and psychiatric conditions, but the mechanisms by which body representations are constructed by the brain are not fully understood. We demonstrate a directional disturbance in tactile identification of the toes in healthy humans. Nineteen young adult participants underwent tactile stimulation of the digits with the eyes closed and verbally reported the identity of the stimulated digit. In the majority of individuals, responses to the second and third toes were significantly biased toward the laterally neighboring digit. The directional bias was greater for the nondominant foot and was affected by the identity of the immediately preceding stimulated toe. Unexpectedly, 9/19 participants reported the subjective experience of a "missing toe" or "missing space" during the protocol. These findings challenge current models of somatosensory localization, as they cannot be explained simply by a lack of distinct representations for toes compared with fingers, or by overt toe-finger correspondences. We present a novel theory of equal spatial representations of digit width combined with a "preceding neighbor" effect to explain the observed phenomena. The diagnostic implications for neurological disorders that involve "digit agnosia" are discussed. © The Author(s) 2015.

Comparative Evaluation of Tactile Sensation by Electrical and Mechanical Stimulation.

Science.gov (United States)

Yem, Vibol; Kajimoto, Hiroyuki

2017-01-01

An electrotactile display is a tactile interface that provides tactile perception by passing electrical current through the surface of the skin. It is actively used instead of mechanical tactile displays for tactile feedback because of several advantages such as its small and thin size, light weight, and high responsiveness. However, the similarities and differences between these sensations is still not clear. This study directly compares the intensity sensation of electrotactile stimulation to that of mechanical stimulation, and investigates the characteristic sensation of anodic and cathodic stimulation. In the experiment, participants underwent a 30 pps electrotactile stimulus every one second to their middle finger, and were asked to match this intensity by adjusting the intensity of a mechanical tactile stimulus to an index finger. The results showed that anodic stimulation mainly produced vibration sensation, whereas cathodic sensation produced both vibration and pressure sensations. Relatively low pressure sensation was also observed for anodic stimulation but it remains low, regardless of the increasing of electrical intensity.

Altered functional magnetic resonance imaging responses to nonpainful sensory stimulation in fibromyalgia patients.

Science.gov (United States)

López-Solà, Marina; Pujol, Jesus; Wager, Tor D; Garcia-Fontanals, Alba; Blanco-Hinojo, Laura; Garcia-Blanco, Susana; Poca-Dias, Violant; Harrison, Ben J; Contreras-Rodríguez, Oren; Monfort, Jordi; Garcia-Fructuoso, Ferran; Deus, Joan

2014-11-01

Fibromyalgia (FM) is a disorder characterized by chronic pain and enhanced responses to acute noxious events. However, the sensory systems affected in FM may extend beyond pain itself, as FM patients show reduced tolerance to non-nociceptive sensory stimulation. Characterizing the neural substrates of multisensory hypersensitivity in FM may thus provide important clues about the underlying pathophysiology of the disorder. The aim of this study was to characterize brain responses to non-nociceptive sensory stimulation in FM patients and their relationship to subjective sensory sensitivity and clinical pain severity. Functional magnetic resonance imaging (MRI) was used to assess brain response to auditory, visual, and tactile motor stimulation in 35 women with FM and 25 matched controls. Correlation and mediation analyses were performed to establish the relationship between brain responses and 3 types of outcomes: subjective hypersensitivity to daily sensory stimulation, spontaneous pain, and functional disability. Patients reported increased subjective sensitivity (increased unpleasantness) in response to multisensory stimulation in daily life. Functional MRI revealed that patients showed reduced task-evoked activation in primary/secondary visual and auditory areas and augmented responses in the insula and anterior lingual gyrus. Reduced responses in visual and auditory areas were correlated with subjective sensory hypersensitivity and clinical severity measures. FM patients showed strong attenuation of brain responses to nonpainful events in early sensory cortices, accompanied by an amplified response at later stages of sensory integration in the insula. These abnormalities are associated with core FM symptoms, suggesting that they may be part of the pathophysiology of the disease. Copyright © 2014 by the American College of Rheumatology.

Design and Qualitative Evaluation of Tactile Devices for Stroke Rehabilitation

OpenAIRE

Merrett, Geoff V; Metcalf, Cheryl D; Zheng, Deyi; Cunningham, Sarah; Barrow, Stuart; Demain, Sara H

2011-01-01

Rehabilitation environments combining virtual reality with everyday motor tasks can promote recovery from neurological illness, such as stroke. Tactile devices, providing physical stimulation to the skin, may improve motor retraining. While many tactile devices have been reported, there is a distinct paucity of studies evaluating how they are perceived. This multidisciplinary research has investigated three tactile devices (vibration motors, a motor-driven ‘squeezer’, and shape memory alloys)...

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

Science.gov (United States)

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.

Tactile mouse generating velvet hand illusion on human palm

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Nadar Rajaei

2016-09-01

Full Text Available To enhance virtual reality (VR generated by tactile displays, we have focused on a novel tactile illusion, called the Velvet Hand Illusion (VHI. In VHI, moving two parallel wires back and forth between the two hands leads humans to perceive a velvet-like surface between their hands. In earlier studies, we revealed that the intensity of VHI could be controlled by a ratio (r/D, where r and D are the wire stroke and wire distance, respectively. According to these findings, we investigate in this study whether a common tactile display is able to produce VHI, and whether the ratio can also control VHI intensity. We prepare a dot-matrix display as a tactile display in which moving one line of the display’s pins is considered as a wire pattern. We investigate the VHI intensity with regard to changing the stroke r and the line distance D using paired comparison. Experimental results show that the VHI intensity is increased or decreased by changing r and D. We conclude that VHI can be created by the tactile display, and the intensity of VHI is controlled by changing the ratio of r/D.

Sensory adaptation to electrical stimulation of the somatosensory nerves.

Science.gov (United States)

Graczyk, Emily Lauren; Delhaye, Benoit; Schiefer, Matthew A; Bensmaia, Sliman J; Tyler, Dustin J

2018-03-19

Sensory systems adapt their sensitivity to ambient stimulation levels to improve their responsiveness to changes in stimulation. The sense of touch is also subject to adaptation, as evidenced by the desensitization produced by prolonged vibratory stimulation of the skin. Electrical stimulation of nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial touch is also subject to adaptation, despite the fact that the peripheral mechanotransducers are bypassed. Approach: Using well-established psychophysical paradigms, we characterize the time course and magnitude of sensory adaptation caused by extended electrical stimulation of the residual somatosensory nerves in three human amputees implanted with cuff electrodes. Main results: We find that electrical stimulation of the nerve also induces perceptual adaptation that recovers after cessation of the stimulus. The time course and magnitude of electrically-induced adaptation are equivalent to their mechanically-induced counterparts. Significance: We conclude that, in natural touch, the process of mechanotransduction is not required for adaptation, and artificial touch naturally experiences adaptation-induced adjustments of the dynamic range of sensations. Further, as it does for native hands, adaptation confers to bionic hands enhanced sensitivity to changes in stimulation and thus a more natural sensory experience. . Creative Commons Attribution license.

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

Science.gov (United States)

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).

Acquisition of multiple prior distributions in tactile temporal order judgment

Directory of Open Access Journals (Sweden)

Yasuhito eNagai

2012-08-01

Full Text Available The Bayesian estimation theory proposes that the brain acquires the prior distribution of a task and integrates it with sensory signals to minimize the effect of sensory noise. Psychophysical studies have demonstrated that our brain actually implements Bayesian estimation in a variety of sensory-motor tasks. However, these studies only imposed one prior distribution on participants within a task period. In this study, we investigated the conditions that enable the acquisition of multiple prior distributions in temporal order judgment (TOJ of two tactile stimuli across the hands. In Experiment 1, stimulation intervals were randomly selected from one of two prior distributions (biased to right hand earlier and biased to left hand earlier in association with color cues (green and red, respectively. Although the acquisition of the two priors was not enabled by the color cues alone, it was significant when participants shifted their gaze (above or below in response to the color cues. However, the acquisition of multiple priors was not significant when participants moved their mouths (opened or closed. In Experiment 2, the spatial cues (above and below were used to identify which eye position or retinal cue position was crucial for the eye-movement-dependent acquisition of multiple priors in Experiment 1. The acquisition of the two priors was significant when participants moved their gaze to the cues (i.e., the cue positions on the retina were constant across the priors, as well as when participants did not shift their gazes (i.e., the cue positions on the retina changed according to the priors. Thus, both eye and retinal cue positions were effective in acquiring multiple priors. Based on previous neurophysiological reports, we discuss possible neural correlates that contribute to the acquisition of multiple priors.

What You Don't Notice Can Harm You: Age-Related Differences in Detecting Concurrent Visual, Auditory, and Tactile Cues.

Science.gov (United States)

Pitts, Brandon J; Sarter, Nadine

2018-06-01

Objective This research sought to determine whether people can perceive and process three nonredundant (and unrelated) signals in vision, hearing, and touch at the same time and how aging and concurrent task demands affect this ability. Background Multimodal displays have been shown to improve multitasking and attention management; however, their potential limitations are not well understood. The majority of studies on multimodal information presentation have focused on the processing of only two concurrent and, most often, redundant cues by younger participants. Method Two experiments were conducted in which younger and older adults detected and responded to a series of singles, pairs, and triplets of visual, auditory, and tactile cues in the absence (Experiment 1) and presence (Experiment 2) of an ongoing simulated driving task. Detection rates, response times, and driving task performance were measured. Results Compared to younger participants, older adults showed longer response times and higher error rates in response to cues/cue combinations. Older participants often missed the tactile cue when three cues were combined. They sometimes falsely reported the presence of a visual cue when presented with a pair of auditory and tactile signals. Driving performance suffered most in the presence of cue triplets. Conclusion People are more likely to miss information if more than two concurrent nonredundant signals are presented to different sensory channels. Application The findings from this work help inform the design of multimodal displays and ensure their usefulness across different age groups and in various application domains.

Speed of reaction to sensory stimulation is enhanced during movement.

Science.gov (United States)

Juravle, Georgiana; Spence, Charles

2015-10-01

We report four experiments on the speed of people's reactions to sensory stimulation while throwing and catching a basketball. Thirty participants participated in Experiment 1, split according to basketball expertise: none, intermediate (6years on average), or advanced (20years or more). The participants had to catch a bouncing basketball. The movement triggered a short tactile pulse in a tactor attached to their wrist to which they made a speeded vocal response (RT). The pulse could be presented either at rest, at two time-points during the reaching movement, or when the hand reached forward to catch the ball. The results indicated that participants responded more rapidly to vibrations on the moving hand relative to preparing or catching the ball, with expert athletes responding significantly faster than novices. In a second experiment, participants made a speeded vocal response to an auditory signal. As in Experiment 1, faster auditory RTs were observed when the hand was moving, as compared to the other time-points. In a third study, the participants responded to a pulse delivered at their resting hand at various time-points corresponding to the average timings of stimulation in Experiment 1. The results revealed comparable RTs across the tested time-points. In a final experiment, the participants made a vocal response to a pulse presented at various time-points while they were throwing the basketball. The results indicated faster tactile RTs while the ball was being thrown. These results are discussed with reference to the literature on goal-directed movements and in terms of current theories of attention and sensory suppression. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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.

Tactile acuity charts: a reliable measure of spatial acuity.

Science.gov (United States)

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.

Psychometric Properties of Dunn\\'s Sensory Profile School Companion

Directory of Open Access Journals (Sweden)

Guita Movallali

2017-10-01

Conclusion The results showed that Dunn's sensory profile has good reliability and validity. Dunn's sensory profile is a useful tool for assessing sensory processing patterns in school and kindergarten settings, and can be used by occupational therapists in clinical environments and by psychologists in educational environments. Information obtained from this profile can have diagnostic value and could also be used for the design of curriculum and classroom space.

Meet our Neighbours - a tactile experience

Science.gov (United States)

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.

Retention of high tactile acuity throughout the life span in blindness.

Science.gov (United States)

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

2008-11-01

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 reexamined this age dependence with two newly designed tactile-acuity charts that require 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 from 12 to 85 years old 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 life span.

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

Science.gov (United States)

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.

Early vision impairs tactile perception in the blind.

Science.gov (United States)

Röder, Brigitte; Rösler, Frank; Spence, Charles

2004-01-20

Researchers have known for more than a century that crossing the hands can impair both tactile perception and the execution of appropriate finger movements. Sighted people find it more difficult to judge the temporal order when two tactile stimuli, one applied to either hand, are presented and their hands are crossed over the midline as compared to when they adopt a more typical uncrossed-hands posture. It has been argued that because of the dominant role of vision in motor planning and execution, tactile stimuli are remapped into externally defined coordinates (predominantly determined by visual inputs) that takes longer to achieve when external and body-centered codes (determined primarily by somatosensory/proprioceptive inputs) are in conflict and that involves both multisensory parietal and visual cortex. Here, we show that the performance of late, but not of congenitally, blind people was impaired by crossing the hands. Moreover, we provide the first empirical evidence for superior temporal order judgments (TOJs) for tactile stimuli in the congenitally blind. These findings suggest a critical role of childhood vision in modulating the perception of touch that may arise from the emergence of specific crossmodal links during development.

Tactile acuity charts: a reliable measure of spatial acuity.

Directory of Open Access Journals (Sweden)

Patrick Bruns

Full Text Available 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.

Performance of Brain-computer Interfacing based on tactile selective sensation and motor imagery

DEFF Research Database (Denmark)

Yao, Lin; Sheng, Xinjun; Mrachacz-Kersting, Natalie

2018-01-01

We proposed a multi-class tactile brain-computer interface that utilizes stimulus-induced oscillatory dynamics. It was hypothesized that somatosensory attention can modulate tactile induced oscillation changes, which can decode different sensation attention tasks. Subjects performed four tactile...

Generalization of a tactile stimulus in horses.

OpenAIRE

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...

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

Science.gov (United States)

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

Oscillatory activity reflects differential use of spatial reference frames by sighted and blind individuals in tactile attention.

Science.gov (United States)

Schubert, Jonathan T W; Buchholz, Verena N; Föcker, Julia; Engel, Andreas K; Röder, Brigitte; Heed, Tobias

2015-08-15

Touch can be localized either on the skin in anatomical coordinates, or, after integration with posture, in external space. Sighted individuals are thought to encode touch in both coordinate systems concurrently, whereas congenitally blind individuals exhibit a strong bias for using anatomical coordinates. We investigated the neural correlates of this differential dominance in the use of anatomical and external reference frames by assessing oscillatory brain activity during a tactile spatial attention task. The EEG was recorded while sighted and congenitally blind adults received tactile stimulation to uncrossed and crossed hands while detecting rare tactile targets at one cued hand only. In the sighted group, oscillatory alpha-band activity (8-12Hz) in the cue-target interval was reduced contralaterally and enhanced ipsilaterally with uncrossed hands. Hand crossing attenuated the degree of posterior parietal alpha-band lateralization, indicating that attention deployment was affected by external spatial coordinates. Beamforming suggested that this posture effect originated in the posterior parietal cortex. In contrast, cue-related lateralization of central alpha-band as well as of beta-band activity (16-24Hz) were unaffected by hand crossing, suggesting that these oscillations exclusively encode anatomical coordinates. In the blind group, central alpha-band activity was lateralized, but did not change across postures. The pattern of beta-band activity was indistinguishable between groups. Because the neural mechanisms for posterior alpha-band generation seem to be linked to developmental vision, we speculate that the lack of this neural mechanism in blind individuals is related to their preferred use of anatomical over external spatial codes in sensory processing. Copyright © 2015 Elsevier Inc. All rights reserved.

Scalable fabric tactile sensor arrays for soft bodies

Science.gov (United States)

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.

Individual Differences in the Rubber Hand Illusion Are Related to Sensory Suggestibility.

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Angela Marotta

Full Text Available In the rubber hand illusion (RHI, watching a rubber hand being stroked in synchrony with one's own hidden hand may induce a sense of ownership over the rubber hand. The illusion relies on bottom-up multisensory integration of visual, tactile, and proprioceptive information, and on top-down processes through which the rubber hand is incorporated into pre-existing representations of the body. Although the degree of illusory experience varies largely across individuals, the factors influencing individual differences are unknown. We investigated whether sensory suggestibility might modulate susceptibility to the RHI. Sensory suggestibility is a personality trait related to how individuals react to sensory information. Because of its sensory nature, this trait could be relevant for studies using the RHI paradigm. Seventy healthy volunteers were classified by Sensory Suggestibility Scale (SSS scores as having high or low suggestibility and assigned to either a high- (High-SSS or a low-suggestibility (Low-SSS group. Two components of the RHI were evaluated in synchronous and asynchronous stroking conditions: subjective experience of sense of ownership over the rubber hand via a 9-statement questionnaire, and proprioceptive drift as measured with a ruler. The High-SSS group was generally more susceptible to the subjective component; in the synchronous condition, they rated the statement assessing the sense of ownership higher than the Low-SSS group. The scores for this statement significantly correlated with the total SSS score, indicating that the higher the sensory suggestibility, the stronger the sense of ownership. No effect of sensory suggestibility on proprioceptive drift was observed, suggesting that the effect is specific for the subjective feeling of ownership. This study demonstrates that sensory suggestibility may contribute to participants' experience of the illusion and should be considered when using the RHI paradigm.

Individual Differences in the Rubber Hand Illusion Are Related to Sensory Suggestibility.

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Marotta, Angela; Tinazzi, Michele; Cavedini, Clelia; Zampini, Massimiliano; Fiorio, Mirta

2016-01-01

In the rubber hand illusion (RHI), watching a rubber hand being stroked in synchrony with one's own hidden hand may induce a sense of ownership over the rubber hand. The illusion relies on bottom-up multisensory integration of visual, tactile, and proprioceptive information, and on top-down processes through which the rubber hand is incorporated into pre-existing representations of the body. Although the degree of illusory experience varies largely across individuals, the factors influencing individual differences are unknown. We investigated whether sensory suggestibility might modulate susceptibility to the RHI. Sensory suggestibility is a personality trait related to how individuals react to sensory information. Because of its sensory nature, this trait could be relevant for studies using the RHI paradigm. Seventy healthy volunteers were classified by Sensory Suggestibility Scale (SSS) scores as having high or low suggestibility and assigned to either a high- (High-SSS) or a low-suggestibility (Low-SSS) group. Two components of the RHI were evaluated in synchronous and asynchronous stroking conditions: subjective experience of sense of ownership over the rubber hand via a 9-statement questionnaire, and proprioceptive drift as measured with a ruler. The High-SSS group was generally more susceptible to the subjective component; in the synchronous condition, they rated the statement assessing the sense of ownership higher than the Low-SSS group. The scores for this statement significantly correlated with the total SSS score, indicating that the higher the sensory suggestibility, the stronger the sense of ownership. No effect of sensory suggestibility on proprioceptive drift was observed, suggesting that the effect is specific for the subjective feeling of ownership. This study demonstrates that sensory suggestibility may contribute to participants' experience of the illusion and should be considered when using the RHI paradigm.

Effect of sensory substitution on suture-manipulation forces for robotic surgical systems.

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Kitagawa, Masaya; Dokko, Daniell; Okamura, Allison M; Yuh, David D

2005-01-01

Direct haptic (force or tactile) feedback is not yet available in commercial robotic surgical systems. Previous work by our group and others suggests that haptic feedback might significantly enhance the execution of surgical tasks requiring fine suture manipulation, specifically those encountered in cardiothoracic surgery. We studied the effects of substituting direct haptic feedback with visual and auditory cues to provide the operating surgeon with a representation of the forces he or she is applying with robotic telemanipulators. Using the robotic da Vinci surgical system (Intuitive Surgical, Inc, Sunnyvale, Calif), we compared applied forces during a standardized surgical knot-tying task under 4 different sensory-substitution scenarios: no feedback, auditory feedback, visual feedback, and combined auditory-visual feedback. The forces applied with these sensory-substitution modes more closely approximate suture tensions achieved under ideal haptic conditions (ie, hand ties) than forces applied without such sensory feedback. The consistency of applied forces during robot-assisted suture tying aided by visual feedback or combined auditory-visual feedback sensory substitution is superior to that achieved with hand ties. Robot-assisted ties aided with auditory feedback revealed levels of consistency that were generally equivalent or superior to those attained with hand ties. Visual feedback and auditory feedback improve the consistency of robotically applied forces. Sensory substitution, in the form of visual feedback, auditory feedback, or both, confers quantifiable advantages in applied force accuracy and consistency during the performance of a simple surgical task.

Sensory over responsivity and obsessive compulsive symptoms: A cluster analysis.

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Ben-Sasson, Ayelet; Podoly, Tamar Yonit

2017-02-01

Several studies have examined the sensory component in Obsesseive Compulsive Disorder (OCD) and described an OCD subtype which has a unique profile, and that Sensory Phenomena (SP) is a significant component of this subtype. SP has some commonalities with Sensory Over Responsivity (SOR) and might be in part a characteristic of this subtype. Although there are some studies that have examined SOR and its relation to Obsessive Compulsive Symptoms (OCS), literature lacks sufficient data on this interplay. First to further examine the correlations between OCS and SOR, and to explore the correlations between SOR modalities (i.e. smell, touch, etc.) and OCS subscales (i.e. washing, ordering, etc.). Second, to investigate the cluster analysis of SOR and OCS dimensions in adults, that is, to classify the sample using the sensory scores to find whether a sensory OCD subtype can be specified. Our third goal was to explore the psychometric features of a new sensory questionnaire: the Sensory Perception Quotient (SPQ). A sample of non clinical adults (n=350) was recruited via e-mail, social media and social networks. Participants completed questionnaires for measuring SOR, OCS, and anxiety. SOR and OCI-F scores were moderately significantly correlated (n=274), significant correlations between all SOR modalities and OCS subscales were found with no specific higher correlation between one modality to one OCS subscale. Cluster analysis revealed four distinct clusters: (1) No OC and SOR symptoms (NONE; n=100), (2) High OC and SOR symptoms (BOTH; n=28), (3) Moderate OC symptoms (OCS; n=63), (4) Moderate SOR symptoms (SOR; n=83). The BOTH cluster had significantly higher anxiety levels than the other clusters, and shared OC subscales scores with the OCS cluster. The BOTH cluster also reported higher SOR scores across tactile, vision, taste and olfactory modalities. The SPQ was found reliable and suitable to detect SOR, the sample SPQ scores was normally distributed (n=350). SOR is a

The sensory channel of presentation alters subjective ratings and autonomic responses towards disgusting stimuli -Blood pressure, heart rate and skin conductance in response to visual, auditory, haptic and olfactory presented disgusting stimuli-

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Ilona eCroy

2013-09-01

Full Text Available Disgust causes specific reaction patterns, observable in mimic responses and body reactions. Most research on disgust deals with visual stimuli. However, pictures may cause another disgust experience than sounds, odors or tactile stimuli. Therefore disgust experience evoked by four different sensory channels was compared.A total of 119 participants received 3 different disgusting and one control stimulus, each presented through the visual, auditory, tactile and olfactory channel. Ratings of evoked disgust as well as responses of the autonomic nervous system (heart rate, skin conductance level, systolic blood pressure were recorded and the effect of stimulus labeling and of repeated presentation was analyzed. Ratings suggested that disgust could be evoked through all senses; they were highest for visual stimuli. However, autonomic reaction towards disgusting stimuli differed according to the channel of presentation. In contrast to the other, olfactory disgust stimuli provoked a strong decrease of systolic blood pressure. Additionally, labeling enhanced disgust ratings and autonomic reaction for olfactory and tactile, but not for visual and auditory stimuli. Repeated presentation indicated that participant’s disgust rating diminishes to all but olfactory disgust stimuli. Taken together we argue that the sensory channel through which a disgust reaction is evoked matters.

A Multi-Sensorial Hybrid Control for Robotic Manipulation in Human-Robot Workspaces

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Juan A. Corrales

2011-10-01

Full Text Available Autonomous manipulation in semi-structured environments where human operators can interact is an increasingly common task in robotic applications. This paper describes an intelligent multi-sensorial approach that solves this issue by providing a multi-robotic platform with a high degree of autonomy and the capability to perform complex tasks. The proposed sensorial system is composed of a hybrid visual servo control to efficiently guide the robot towards the object to be manipulated, an inertial motion capture system and an indoor localization system to avoid possible collisions between human operators and robots working in the same workspace, and a tactile sensor algorithm to correctly manipulate the object. The proposed controller employs the whole multi-sensorial system and combines the measurements of each one of the used sensors during two different phases considered in the robot task: a first phase where the robot approaches the object to be grasped, and a second phase of manipulation of the object. In both phases, the unexpected presence of humans is taken into account. This paper also presents the successful results obtained in several experimental setups which verify the validity of the proposed approach.

Introducing the tactile speller: an ERP-based brain-computer interface for communication

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van der Waal, Marjolein; Severens, Marianne; Geuze, Jeroen; Desain, Peter

2012-08-01

In this study, a tactile speller was developed and compared with existing visual speller paradigms in terms of classification performance and elicited event-related potentials (ERPs). The fingertips of healthy participants were stimulated with short mechanical taps while electroencephalographic activity was measured. The letters of the alphabet were allocated to different fingers and subjects could select one of the fingers by silently counting the number of taps on that finger. The offline and online performance of the tactile speller was compared to the overt and covert attention visual matrix speller and the covert attention Hex-o-Spell speller. For the tactile speller, binary target versus non-target classification accuracy was 67% on average. Classification and decoding accuracies of the tactile speller were lower than the overt matrix speller, but higher than the covert matrix speller, and similar to Hex-o-Spell. The average maximum information transfer rate of the tactile speller was 7.8 bits min-1 (1.51 char min-1), with the best subject reaching a bit-rate of 27 bits min-1 (5.22 char min-1). An increased amplitude of the P300 ERP component was found in response to attended stimuli versus unattended stimuli in all speller types. In addition, the tactile and overt matrix spellers also used the N2 component for discriminating between targets and non-targets. Overall, this study shows that it is possible to use a tactile speller for communication. The tactile speller provides a useful alternative to the visual speller, especially for people whose eye gaze is impaired.

TMS-induced neural noise in sensory cortex interferes with short-term memory storage

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Tyler D Bancroft

2014-03-01

Full Text Available In a previous study, Harris et al. (2002 found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation to primary somatosensory cortex (SI early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.’s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature.

Use of a forced-choice test of tactile discrimination in the evaluation of functional sensory loss: a report of 3 cases.

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Greve, Kevin W; Bianchini, Kevin J; Ameduri, Clifford J

2003-08-01

The loss of sensation is not an uncommon associated finding after injury to the peripheral nerves and the spinal cord. However, the sensory examination is prone to the influence of nonphysiologic factors, and one cannot use it to determine whether functional sensory loss reflects unconscious or intentional symptom production. This distinction has important implications for differential diagnosis and for decision making in the context of workers' compensation claims and personal injury litigation. We present 3 cases of patients with chronic pain and nondermatomal patterns of loss of fine-touch sensation, whose sensory loss was examined by a sensory forced-choice symptom validity test. Their below-chance scores showed intentionally produced sensory symptoms. The use of this methodology in differential diagnosis is discussed.

Effect of Electrostatic Tactile Feedback on Accuracy and Efficiency of Pan Gestures on Touch Screens.

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Liu, Guohong; Sun, Xiaoying; Wang, Dangxiao; Liu, Yue; Zhang, Yuru

2018-01-01

Recently, many studies examined electrostatic tactile feedback on touch screens to enrich interaction experience. However, it is unclear as to whether added tactile feedback during a sliding process increases the accuracy of pan gestures with velocity constraints. In this study, a custom-designed electrostatic tactile display was considered. Initially, the accuracy and efficiency of pan gestures were compared under two conditions, namely with and without electrostatic tactile feedback. This was followed by exploring the evolution of completion time (CT) with different indices of difficulties (ID). Experimental results with 12 participants indicated that the accuracy and completion time of pan gestures with added tactile feedback significantly exceeded those without tactile feedback. Furthermore, the relationship between CT and ID satisfied Fitts' Law with a correlation coefficient exceeding 0.9. Based on the findings, a "Tactile Fruit Sorting" game was designed, and subjective and objective evaluations were conducted. The results confirmed that the added tactile feedback enhanced both user performance and interest with respect to the game.

The sensory construction of dreams and nightmare frequency in congenitally blind and late blind individuals.

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Meaidi, Amani; Jennum, Poul; Ptito, Maurice; Kupers, Ron

2014-05-01

We aimed to assess dream content in groups of congenitally blind (CB), late blind (LB), and age- and sex-matched sighted control (SC) participants. We conducted an observational study of 11 CB, 14 LB, and 25 SC participants and collected dream reports over a 4-week period. Every morning participants filled in a questionnaire related to the sensory construction of the dream, its emotional and thematic content, and the possible occurrence of nightmares. We also assessed participants' ability of visual imagery during waking cognition, sleep quality, and depression and anxiety levels. All blind participants had fewer visual dream impressions compared to SC participants. In LB participants, duration of blindness was negatively correlated with duration, clarity, and color content of visual dream impressions. CB participants reported more auditory, tactile, gustatory, and olfactory dream components compared to SC participants. In contrast, LB participants only reported more tactile dream impressions. Blind and SC participants did not differ with respect to emotional and thematic dream content. However, CB participants reported more aggressive interactions and more nightmares compared to the other two groups. Our data show that blindness considerably alters the sensory composition of dreams and that onset and duration of blindness plays an important role. The increased occurrence of nightmares in CB participants may be related to a higher number of threatening experiences in daily life in this group. Copyright © 2014 Elsevier B.V. All rights reserved.

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

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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.

Making sense. What can we learn from experts of tactile knowledge?

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Camilla Groth

2013-09-01

Full Text Available This article describes an embodied way of making sense through making with the hands. We examine the potential o ftactile experience in the making process and analyse what tactile experiences mean. The study takes place in the context of an era marked by audio-visual dominance.The article presents a case study that observed and interviewed deafblind makers while they worked with clay. The findings reveal that modelling in clay resembles the visualisation process of sketching. As such, it may contribute to thinking through the hands. Language is not a self-evident communication tool for transferring tactile skills. Based on our case study, we propose the use of tactile communication in the process of transferring tactile knowledge through making with another person’s hands.

Autistic Traits and Abnormal Sensory Experiences in Adults

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Horder, Jamie; Wilson, C. Ellie; Mendez, M. Andreina; Murphy, Declan G.

2014-01-01

Sensory processing abnormalities are common in autism spectrum disorders (ASD), and now form part of the "Diagnostic and Statistical Manual 5th Edition" (DSM-5) diagnostic criteria, but it is unclear whether they characterize the "broader phenotype" of the disorder. We recruited adults (n = 772) with and without an ASD and…

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

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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.

AWARENESS: Tactility and Experience as Transformational Strategy

DEFF Research Database (Denmark)

Riisberg, Vibeke; Bang, Anne Louise; Locher, Laura

2015-01-01

with users. By employing participatory methods in the field of fashion and textiles, we seek to develop an alternative transformational strategy that may further the design of products and services for a more sustainable future. In the initial theoretical section, we define tactile sensibility, which...... “tacit knowledge” and a “tacit experience”. Finally, we conclude that if designers wish to promote change related to sustainability, it is likely that an embodied participatory dialogue that builds on the combination of user experience and tactile sensibility can be further developed into didactic tools...

Quantitative sensory testing of temperature, pain, and touch in adults with Down syndrome.

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de Knegt, Nanda; Defrin, Ruth; Schuengel, Carlo; Lobbezoo, Frank; Evenhuis, Heleen; Scherder, Erik

2015-12-01

The spinothalamic pathway mediates sensations of temperature, pain, and touch. These functions seem impaired in children with Down syndrome (DS), but have not been extensively examined in adults. The objective of the present study was to compare the spinothalamic-mediated sensory functions between adults with DS and adults from the general population and to examine in the DS group the relationship between the sensory functions and level of intellectual functioning. Quantitative sensory testing (QST) was performed in 188 adults with DS (mean age 37.5 years) and 142 age-matched control participants (median age 40.5 years). Temperature, pain, and touch were evaluated with tests for cold-warm discrimination, sharp-dull discrimination (pinprick), and tactile threshold, respectively. Level of intellectual functioning was estimated with the Social Functioning Scale for Intellectual Disability (intellectual disability level) and the Wechsler Preschool and Primary Scale of Intelligence--Revised (intelligence level). Overall, the difference in spinothalamic-mediated sensory functions between the DS and control groups was not statistically significant. However, DS participants with a lower intelligence level had a statistically significant lower performance on the sharp-dull discrimination test than DS participants with higher intelligence level (adjusted p=.006) and control participants (adjusted p=.017). It was concluded that intellectual functioning level is an important factor to take into account for the assessment of spinothalamic-mediated sensory functioning in adults with DS: a lower level could coincide with impaired sensory functioning, but could also hamper QST assessment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tactile spatial acuity in childhood: effects of age and fingertip size.

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Ryan M Peters

Full Text Available Tactile acuity is known to decline with age in adults, possibly as the result of receptor loss, but less is understood about how tactile acuity changes during childhood. Previous research from our laboratory has shown that fingertip size influences tactile spatial acuity in young adults: those with larger fingers tend to have poorer acuity, possibly because mechanoreceptors are more sparsely distributed in larger fingers. We hypothesized that a similar relationship would hold among children. If so, children's tactile spatial acuity might be expected to worsen as their fingertips grow. However, concomitant CNS maturation might result in more efficient perceptual processing, counteracting the effect of fingertip growth on tactile acuity. To investigate, we conducted a cross-sectional study, testing 116 participants ranging in age from 6 to 16 years on a precision-controlled tactile grating orientation task. We measured each participant's grating orientation threshold on the dominant index finger, along with physical properties of the fingertip: surface area, volume, sweat pore spacing, and temperature. We found that, as in adults, children with larger fingertips (at a given age had significantly poorer acuity, yet paradoxically acuity did not worsen significantly with age. We propose that finger growth during development results in a gradual decline in innervation density as receptive fields reposition to cover an expanding skin surface. At the same time, central maturation presumably enhances perceptual processing.

TRPM7 is required within zebrafish sensory neurons for the activation of touch-evoked escape behaviors

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Low, Sean E.; Amburgey, Kimberly; Horstick, Eric; Linsley, Jeremy; Sprague, Shawn M.; Cui, Wilson W.; Zhou, Weibin; Hirata, Hiromi; Saint-Amant, Louis; Hume, Richard I.; Kuwada, John Y.

2011-01-01

Mutations in the gene encoding TRPM7 (trpm7), a member of the TRP superfamily of cation channels that possesses an enzymatically active kinase at its carboxyl terminus, cause the touch-unresponsive zebrafish mutant touchdown. We identified and characterized a new allele of touchdown, as well as two previously reported alleles, and found that all three alleles harbor mutations which abolish channel activity. Through the selective restoration of TRPM7 expression in sensory neurons we found that TRPM7’s kinase activity, and selectivity for divalent cations over monovalent cations, were dispensable for touch-evoked activation of escape behaviors in zebrafish. Additional characterization revealed that sensory neurons were present and capable of responding to tactile stimuli in touchdown mutants, indicating that TRPM7 is not required for sensory neuron survival or mechanosensation. Finally, exposure to elevated concentrations of divalent cations was found to restore touch-evoked behaviors in touchdown mutants. Collectively these findings are consistent with a role for zebrafish TRPM7 within sensory neurons in the modulation of neurotransmitter release at central synapses, similar to that proposed for mammalian TRPM7 at peripheral synapses. PMID:21832193

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

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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.

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

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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.

Interhemispheric Inhibition Induced by Transcranial Magnetic Stimulation Over Primary Sensory Cortex.

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Iwata, Yasuyuki; Jono, Yasutomo; Mizusawa, Hiroki; Kinoshita, Atsushi; Hiraoka, Koichi

2016-01-01

The present study investigated whether the long-interval interhemispheric inhibition (LIHI) is induced by the transcranial magnetic stimulation over the primary sensory area (S1-TMS) without activation of the conditioning side of the primary motor area (M1) contributing to the contralateral motor evoked potential (MEP), whether the S1-TMS-induced LIHI is dependent on the status of the S1 modulated by the tactile input, and whether the pathways mediating the LIHI are different from those mediating the M1-TMS-induced LIHI. In order to give the TMS over the S1 without eliciting the MEP, the intensity of the S1-TMS was adjusted to be the sub-motor-threshold level and the trials with the MEP response elicited by the S1-TMS were discarded online. The LIHI was induced by the S1-TMS given 40 ms before the test TMS in the participants with the attenuation of the tactile perception of the digit stimulation (TPDS) induced by the S1-TMS, indicating that the LIHI is induced by the S1-TMS without activation of the conditioning side of the M1 contributing to the contralateral MEP in the participants in which the pathways mediating the TPDS is sensitive to the S1-TMS. The S1-TMS-induced LIHI was positively correlated with the attenuation of the TPDS induced by the S1-TMS, indicating that the S1-TMS-induced LIHI is dependent on the effect of the S1-TMS on the pathways mediating the TPDS at the S1. In another experiment, the effect of the digit stimulation given before the conditioning TMS on the S1- or M1-TMS-induced LIHI was examined. The digit stimulation produces tactile input to the S1 causing change in the status of the S1. The S1-TMS-induced LIHI was enhanced when the S1-TMS was given in the period in which the tactile afferent volley produced by the digit stimulation just arrived at the S1, while the LIHI induced by above-motor-threshold TMS over the contralateral M1 was not enhanced by the tactile input. Thus, the S1-TMS-induced LIHI is dependent on the status of the S1

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

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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.

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

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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…

Evaluating tactile feedback in robotic surgery for potential clinical application using an animal model.

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Wottawa, Christopher R; Genovese, Bradley; Nowroozi, Bryan N; Hart, Steven D; Bisley, James W; Grundfest, Warren S; Dutson, Erik P

2016-08-01

The aims of this study were to evaluate (1) grasping forces with the application of a tactile feedback system in vivo and (2) the incidence of tissue damage incurred during robotic tissue manipulation. Robotic-assisted minimally invasive surgery has been shown to be beneficial in a variety of surgical specialties, particularly radical prostatectomy. This innovative surgical tool offers advantages over traditional laparoscopic techniques, such as improved wrist-like maneuverability, stereoscopic video displays, and scaling of surgical gestures to increase precision. A widely cited disadvantage associated with robotic systems is the absence of tactile feedback. Nineteen subjects were categorized into two groups: 5 experts (six or more robotic cases) and 14 novices (five cases or less). The subjects used the da Vinci with integrated tactile feedback to run porcine bowel in the following conditions: (T1: deactivated tactile feedback; T2: activated tactile feedback; and T3: deactivated tactile feedback). The grasping force, incidence of tissue damage, and the correlation of grasping force and tissue damage were analyzed. Tissue damage was evaluated both grossly and histologically by a pathologist blinded to the sample. Tactile feedback resulted in significantly decreased grasping forces for both experts and novices (P system was deactivated (P > 0.05 in all subjects). The in vivo application of integrated tactile feedback in the robotic system demonstrates significantly reduced grasping forces, resulting in significantly less tissue damage. This tactile feedback system may improve surgical outcomes and broaden the use of robotic-assisted minimally invasive surgery.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Research for improved flexible tactile sensor sensitivity

International Nuclear Information System (INIS)

Yun, Hae Yong; Kim, Ho Chan; Lee, In Hwan

2015-01-01

With the development of robotic technologies, in recent years these technologies have been applied to multidisciplinary fields of study. To operate similarly to a human being, many robot technologies require devices that can receive exterior stimulus, temperature, visual data, and the sense of smell, etc. The robot's hand needs sensor devices that can receive exterior stimuli in order to operate similarly to human skin. The flexible tactile sensor for the robot has to be manufactured to have a shape similar to the shape of human skin. The research studied the development of a system and materials that will enable exterior stimuli to be received effectively. This research used carbon nano tube as a material. Carbon nano tube is used because it has a high electrical conductivity and outstanding mechanical characteristics. In addition, the two composite Materials are used to improve the stimulation sensitivity at different rates, the flexible tactile sensor to measure the sensitivity. Using 3D printing technology, the fabrication of a flexible tactile sensor system is introduced.

Research for improved flexible tactile sensor sensitivity

Energy Technology Data Exchange (ETDEWEB)

Yun, Hae Yong; Kim, Ho Chan [Andong National University, Andong (Korea, Republic of); Lee, In Hwan [Chungbuk National University, Chungju (Korea, Republic of)

2015-11-15

With the development of robotic technologies, in recent years these technologies have been applied to multidisciplinary fields of study. To operate similarly to a human being, many robot technologies require devices that can receive exterior stimulus, temperature, visual data, and the sense of smell, etc. The robot's hand needs sensor devices that can receive exterior stimuli in order to operate similarly to human skin. The flexible tactile sensor for the robot has to be manufactured to have a shape similar to the shape of human skin. The research studied the development of a system and materials that will enable exterior stimuli to be received effectively. This research used carbon nano tube as a material. Carbon nano tube is used because it has a high electrical conductivity and outstanding mechanical characteristics. In addition, the two composite Materials are used to improve the stimulation sensitivity at different rates, the flexible tactile sensor to measure the sensitivity. Using 3D printing technology, the fabrication of a flexible tactile sensor system is introduced.

Supramodal Theta, Gamma, and Sustained Fields Predict Modality-specific Modulations of Alpha and Beta Oscillations during Visual and Tactile Working Memory.

Science.gov (United States)

van Ede, Freek; Jensen, Ole; Maris, Eric

2017-08-01

Flexible control over currently relevant sensory representations is an essential feature of primate cognition. We investigated the neurophysiological bases of such flexible control in humans during an intermodal working memory task in which participants retained visual or tactile sequences. Using magnetoencephalography, we first show that working memory retention engages early visual and somatosensory areas, as reflected in the sustained load-dependent suppression of alpha and beta oscillations. Next, we identify three components that are also load dependent but modality independent: medial prefrontal theta synchronization, frontoparietal gamma synchronization, and sustained parietal event-related fields. Critically, these domain-general components predict (across trials and within load conditions) the modality-specific suppression of alpha and beta oscillations, with largely unique contributions per component. Thus, working memory engages multiple complementary frontoparietal components that have discernible neuronal dynamics and that flexibly modulate retention-related activity in sensory areas in a manner that tracks the current contents of working memory.

A Prototype Tactile Sensor Array.

Science.gov (United States)

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

Flexible PZT Thin Film Tactile Sensor for Biomedical Monitoring

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Wen-Jong Wu

2013-04-01

Full Text Available 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.

Flexible PZT thin film tactile sensor for biomedical monitoring.

Science.gov (United States)

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.

Small-scale tactile graphics for virtual reality systems

Science.gov (United States)

Roberts, John W.; Slattery, Oliver T.; Swope, Brett; Min, Volker; Comstock, Tracy

2002-05-01

As virtual reality technology moves forward, there is a need to provide the user with options for greater realism for closer engagement to the human senses. Haptic systems use force feedback to create a large-scale sensation of physical interaction in a virtual environment. Further refinement can be created by using tactile graphics to reproduce a detailed sense of touch. For example, a haptic system might create the sensation of the weight of a virtual orange that the user picks up, and the sensation of pressure on the fingers as the user squeezes the orange. A tactile graphic system could create the texture of the orange on the user's fingertips. IN the real wold, a detailed sense of touch plays a large part in picking up and manipulating small objects. Our team is working to develop technology that can drive a high density fingertip array of tactile simulators at a rapid refresh rate, sufficient to produce a realistic sense of touch. To meet the project criteria, the mechanism must be much lower cost than existing technologies, and must be sufficiently lightweight and compact to permit portable use and to enable installation of the stimulator array in the fingertip of a tactile glove. The primary intended applications for this technology are accessibility for the blind and visually impaired, teleoperation, and virtual reality systems.

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

Directory of Open Access Journals (Sweden)

Ramiro Velázquez

2015-01-01

Full Text Available 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.

Application of artificial tactile sensing approach in kidney-stone-removal laparoscopy.

Science.gov (United States)

Afshari, Elnaz; Najarian, Siamak; Simforoosh, Nasser

2010-01-01

Artificial tactile sensing is a novel method for obtaining different characteristics of a hard object embedded in a soft tissue. In this regard, artificial palpation is one of the most valuable achievements of artificial tactile sensing that can be used in various fields of medicine and more specifically in surgery. In this study, considering the present problems and limitations in kidney-stone-removal laparoscopy, a new application will be presented for artificial tactile sensing approach. Having imitated surgeon's palpation during open surgery and modeled it conceptually, indications of stone existence that appear on the surface of kidney (due to exerting mechanical load) were determined. A number of different cases were created and solved by the software. Using stress distribution contours and stress graphs, it is illustrated that the created stress patterns on the surface of kidney not only show the existence of stone inside, but also its exact location. In fact, the reliability and accuracy of artificial tactile sensing method in detection of kidney stone during laparoscopy is demonstrated by means of finite element analysis. Also, in this paper, the functional principles of tactile system capable of determining the exact location of stone during laparoscopy will be presented.

3D Printing Technologies for Flexible Tactile Sensors toward Wearable Electronics and Electronic Skin

Directory of Open Access Journals (Sweden)

Changyong Liu

2018-06-01

Full Text Available 3D printing has attracted a lot of attention in recent years. Over the past three decades, various 3D printing technologies have been developed including photopolymerization-based, materials extrusion-based, sheet lamination-based, binder jetting-based, power bed fusion-based and direct energy deposition-based processes. 3D printing offers unparalleled flexibility and simplicity in the fabrication of highly complex 3D objects. Tactile sensors that emulate human tactile perceptions are used to translate mechanical signals such as force, pressure, strain, shear, torsion, bend, vibration, etc. into electrical signals and play a crucial role toward the realization of wearable electronics and electronic skin. To date, many types of 3D printing technologies have been applied in the manufacturing of various types of tactile sensors including piezoresistive, capacitive and piezoelectric sensors. This review attempts to summarize the current state-of-the-art 3D printing technologies and their applications in tactile sensors for wearable electronics and electronic skin. The applications are categorized into five aspects: 3D-printed molds for microstructuring substrate, electrodes and sensing element; 3D-printed flexible sensor substrate and sensor body for tactile sensors; 3D-printed sensing element; 3D-printed flexible and stretchable electrodes for tactile sensors; and fully 3D-printed tactile sensors. Latest advances in the fabrication of tactile sensors by 3D printing are reviewed and the advantages and limitations of various 3D printing technologies and printable materials are discussed. Finally, future development of 3D-printed tactile sensors is discussed.

EAP application to artificial tactile feel display of virtual reality

Science.gov (United States)

Konyo, Masashi; Tadokoro, Satoshi; Takamori, Toshi; Oguro, Keisuke

2001-07-01

A tactile feel display device for virtual reality was developed using Nafion-Platinum composite type EAP actuator (known as IPMC or ICPF). Conventional tactile displays can hardly express tactile human feeling of the fine touch of the surface of a cloth, because their mechanisms cannot excite minute distributed stimuli on human skin. We propose a new ciliary device using ICPF actuators. The ICPF has sufficient softness, utilizing the passive material property, that complex control is not required. The low drive voltage is safe enough for the touch of fingers. Its simple operation mechanism allows miniaturization for practical equipments. The developed device was designed with a number of cilia consisting of ICPF actuators, where a cilium is 2 mm wide and 5 mm long. An ICPF membrane is cut into pectination, and only the cilium part is plated and has a function of an actuator. An inclined configuration of the cilia produces variety of stimuli to human skin controlling frequencies. We tried to display both pressure and vibration at the same time using modulated low and high frequencies. The result clearly shows that over 80% of the subjects sensed some special tactile feeling. A comparison with real material samples shows that this display can present a subtle distinction of tactile feeling of cloth, especially like a towel and denim.

Neural correlates associated with superior tactile symmetry perception in the early blind

OpenAIRE

Bauer, Corinna; Yazzolino, Lindsay; Hirsch, Gabriella; Cattaneo, Zaira; Vecchi, Tomaso; Merabet, Lotfi B.

2014-01-01

Symmetry is an organizational principle that is ubiquitous throughout the visual world. However, this property can also be detected through non-visual modalities such as touch. The role of prior visual experience on detecting tactile patterns containing symmetry remains unclear. We compared the behavioral performance of early blind and sighted (blindfolded) controls on a tactile symmetry detection task. The tactile patterns used were similar in design and complexity as in previous visual perc...

El universo plástico y sensorial de la mano (Wong Kar Wai, 2004

Directory of Open Access Journals (Sweden)

Ana MELENDO CRUZ

2014-10-01

Full Text Available In this article, we show how Wong Kar Wai, heir to a filmography closely linked to cinematographic modernity, explores themes such as loneliness, melancholy, or self-absorption in his short film The Hand (2004. These themes, together with his study of geometry, saturated colours and pictorial qualities through the prism of metaphysical realism, give rise to purely optical, sonorous and tactile situations. In this way, the Chinese film director reveals, through the presence of a body fragment and metonymy, the colourful and sonorous textures that form the sensory-motor spaces of the underworld in which the story is set

A new paradigm of electrical stimulation to enhance sensory neural function.

Science.gov (United States)

Breen, Paul P; ÓLaighin, Gearóid; McIntosh, Caroline; Dinneen, Sean F; Quinlan, Leo R; Serrador, Jorge M

2014-08-01

The ability to improve peripheral neural transmission would have significant therapeutic potential in medicine. A technology of this kind could be used to restore and/or enhance sensory function in individuals with depressed sensory function, such as older adults or patients with peripheral neuropathies. The goal of this study was to investigate if a new paradigm of subsensory electrical noise stimulation enhances somatosensory function. Vibration (50Hz) was applied with a Neurothesiometer to the plantar aspect of the foot in the presence or absence of subsensory electrical noise (1/f type). The noise was applied at a proximal site, on a defined region of the tibial nerve path above the ankle. Vibration perception thresholds (VPT) of younger adults were measured in control and experimental conditions, in the absence or presence of noise respectively. An improvement of ∼16% in VPT was found in the presence of noise. These are the first data to demonstrate that modulation of axonal transmission with externally applied electrical noise improves perception of tactile stimuli in humans. Copyright © 2014 IPEM. All rights reserved.

Tactile Data Entry System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Building on our successful Phase I Tactile Data Entry program, Barron Associates proposes development of a Glove-Enabled Computer Operations (GECO) system to permit...

Tactile display for virtual 3D shape rendering

CERN Document Server

Mansutti, Alessandro; Bordegoni, Monica; Cugini, Umberto

2017-01-01

This book describes a novel system for the simultaneous visual and tactile rendering of product shapes which allows designers to simultaneously touch and see new product shapes during the conceptual phase of product development. This system offers important advantages, including potential cost and time savings, compared with the standard product design process in which digital 3D models and physical prototypes are often repeatedly modified until an optimal design is achieved. The system consists of a tactile display that is able to represent, within a real environment, the shape of a product. Designers can explore the rendered surface by touching curves lying on the product shape, selecting those curves that can be considered style features and evaluating their aesthetic quality. In order to physically represent these selected curves, a flexible surface is modeled by means of servo-actuated modules controlling a physical deforming strip. The tactile display is designed so as to be portable, low cost, modular,...

Brief Report: DSM-5 Sensory Behaviours in Children with and without an Autism Spectrum Disorder

Science.gov (United States)

Green, Dido; Chandler, Susie; Charman, Tony; Simonoff, Emily; Baird, Gillian

2016-01-01

Atypical responses to sensory stimuli are a new criterion in DSM-5 for the diagnosis of an autism spectrum disorder (ASD) but are also reported in other developmental disorders. Using the Short Sensory profile (SSP) and Autism Diagnostic Interview-Revised we compared atypical sensory behaviour (hyper- or hypo-reactivity to sensory input or unusual…

City Walks and Tactile Experience

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Mădălina Diaconu

2011-01-01

Full Text Available This paper is an attempt to develop categories of the pedestrian’s tactile and kinaesthetic experience of the city. The beginning emphasizes the haptic qualities of surfaces and textures, which can be “palpated” visually or experienced by walking. Also the lived city is three-dimensional; its corporeal depth is discussed here in relation to the invisible sewers, protuberant profiles, and the formal diversity of roofscapes. A central role is ascribed in the present analysis to the formal similarities between the representation of the city by walking through it and the representation of the tactile form of objects. Additional aspects of the “tactile” experience of the city in a broad sense concern the feeling of their rhythms and the exposure to weather conditions. Finally, several aspects of contingency converge in the visible age of architectural works, which record traces of individual and collective histories.

Vestibulo-tactile interactions regarding motion perception and eye movements in yaw

NARCIS (Netherlands)

Bos, J.E.; Erp, J.B.F. van; Groen, E.L.; Veen, H.J. van

2005-01-01

This paper shows that tactile stimulation can override vestibular information regarding spinning sensations and eye movements. However, we conclude that the current data do not support the hypothesis that tactile stimulation controls eye movements directly. To this end, twenty-four subjects were

A microfabricated strain gauge array on polymer substrate for tactile neuroprostheses in rats

International Nuclear Information System (INIS)

Beygi, M; Mutlu, S; Güçlü, B

2016-01-01

In this study, we present the design, microfabrication and characterization of a tactile sensor system which can be used for sensory neuroprostheses in rats. The sensor system consists of an array of 2  ×  7 cells, each of which has a series combination of four strain gauges. Each group of four strain gauges is placed around a square membrane with a size of 2.5  ×  2.5 mm 2 . Unlike most common tactile sensors based on silicon substrates, we used 3D-printed polylactic acid as a substrate, because it is not brittle, and under local extremes, it would prevent the catastrophic failure of all cells. The strain gauges were fabricated by depositing and patterning a 50 nm thick aluminum (Al) film on a polyimide sheet with a thickness of 0.125 mm. Polydimethylsiloxane (PDMS) elastomer was bonded on the top surface of the PI membrane. The PDMS layer was prepared in two different thicknesses, 1.2 and 1.7 mm, to investigate its effect on the static response of the sensor. The sensitivity and the maximum allowable force, corresponding to the maximum deformation of 0.9 mm at the center of each cell, changed based on the thickness of the PDMS layer. Sensor cells operated linearly up to 3 N with an average sensitivity of 200 mΩ N −1 (0.7 Ω mm −1 ) for 1.2 mm thick PDMS. These values changed to 4 N and 70 mΩ N −1 (0.3 Ω mm −1 ), respectively, for 1.7 mm thick PDMS. The nonlinearity was less than 3%. The cells had low cross-talk (∼5 mΩ N −1 and 0.02 Ω mm −1 ) relative to the average sensitivity. Additionally, the dynamic response of the sensor was characterized at several frequencies by using a vibrotactile stimulation system previously designed for psychophysics experiments. The sensor was also tested inside the rat conditioning chamber to demonstrate the relevant signals in a tactile neuroprosthesis. (paper)

A microfabricated strain gauge array on polymer substrate for tactile neuroprostheses in rats

Science.gov (United States)

Beygi, M.; Mutlu, S.; Güçlü, B.

2016-08-01

In this study, we present the design, microfabrication and characterization of a tactile sensor system which can be used for sensory neuroprostheses in rats. The sensor system consists of an array of 2  ×  7 cells, each of which has a series combination of four strain gauges. Each group of four strain gauges is placed around a square membrane with a size of 2.5  ×  2.5 mm2. Unlike most common tactile sensors based on silicon substrates, we used 3D-printed polylactic acid as a substrate, because it is not brittle, and under local extremes, it would prevent the catastrophic failure of all cells. The strain gauges were fabricated by depositing and patterning a 50 nm thick aluminum (Al) film on a polyimide sheet with a thickness of 0.125 mm. Polydimethylsiloxane (PDMS) elastomer was bonded on the top surface of the PI membrane. The PDMS layer was prepared in two different thicknesses, 1.2 and 1.7 mm, to investigate its effect on the static response of the sensor. The sensitivity and the maximum allowable force, corresponding to the maximum deformation of 0.9 mm at the center of each cell, changed based on the thickness of the PDMS layer. Sensor cells operated linearly up to 3 N with an average sensitivity of 200 mΩ N-1 (0.7 Ω mm-1) for 1.2 mm thick PDMS. These values changed to 4 N and 70 mΩ N-1 (0.3 Ω mm-1), respectively, for 1.7 mm thick PDMS. The nonlinearity was less than 3%. The cells had low cross-talk (~5 mΩ N-1 and 0.02 Ω mm-1) relative to the average sensitivity. Additionally, the dynamic response of the sensor was characterized at several frequencies by using a vibrotactile stimulation system previously designed for psychophysics experiments. The sensor was also tested inside the rat conditioning chamber to demonstrate the relevant signals in a tactile neuroprosthesis.

The interaction between felt touch and tactile consequences of observed actions: an action-based somatosensory congruency paradigm.

Science.gov (United States)

Deschrijver, Eliane; Wiersema, Jan R; Brass, Marcel

2016-07-01

Action observation leads to a representation of both the motor aspect of an observed action (motor simulation) and its somatosensory consequences (action-based somatosensory simulation) in the observer's brain. In the current electroencephalography-study, we investigated the neuronal interplay of action-based somatosensory simulation and felt touch. We presented index or middle finger tapping movements of a human or a wooden hand, while simultaneously presenting 'tap-like' tactile sensations to either the corresponding or non-corresponding fingertip of the participant. We focused on an early stage of somatosensory processing [P50, N100 and N140 sensory evoked potentials (SEPs)] and on a later stage of higher-order processing (P3-complex). The results revealed an interaction effect of animacy and congruency in the early P50 SEP and an animacy effect in the N100/N140 SEPs. In the P3-complex, we found an interaction effect indicating that the influence of congruency was larger in the human than in the wooden hand. We argue that the P3-complex may reflect higher-order self-other distinction by signaling simulated action-based touch that does not match own tactile information. As such, the action-based somatosensory congruency paradigm might help understand higher-order social processes from a somatosensory point of view. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Sensory Processing Difficulties in Toddlers With Nonorganic Failure-to-Thrive and Feeding Problems.

Science.gov (United States)

Yi, Sook-Hee; Joung, Yoo-Sook; Choe, Yon Ho; Kim, Eun-Hye; Kwon, Jeong-Yi

2015-06-01

Failure-to-thrive is defined as an abnormally low weight and/or height for age. The term "nonorganic failure-to-thrive" (NOFT) has been used to describe "failure-to-thrive" without an obvious cause underlying the growth failure. The purpose of the present study was to compare sensory processing abilities between toddlers with NOFT and feeding problems and age-matched controls. Toddlers with NOFT and feeding problems (N = 16) were recruited from the pediatric feeding clinic in a tertiary university hospital, and age-matched controls (N = 16) were recruited from community volunteers. They were evaluated for sensory processing ability using an Infant/Toddler Sensory Profile (ITSP), and for development of cognition, motor skills, and language using the Bayley Scales of Infant Development II and Sequenced Language Scale for Infants. Behavior at mealtime was evaluated using the Behavioral Pediatrics Feeding Assessment Scale. In the NOFT with feeding problems group, atypical performances were more frequently observed in 3 of 5 ITSP section items (tactile, vestibular, and oral) compared with those in the control group. Significant delayed development of cognition, motor skills, and language was observed in the NOFT with feeding problems group compared with that in the control group. In addition, children who showed 1 or more atypical performances in ITSP had delayed development in cognition, motor skills, and language. Sensory processing problems were more commonly observed in toddlers with feeding problems and growth deficiency. The present study could provide a preliminary evidence for a possible impact of the sensory processing problems on the feeding difficulties in toddlers with NOFT. Future large studies should be conducted to clarify the relation between sensory processing difficulties and feeding problems in toddlers.

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

Science.gov (United States)

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 sensibility in digital nerve injuries without combined nerve, tendon, and bone injuries.

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

Science.gov (United States)

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%.

Bilateral Symmetry of Distortions of Tactile Size Perception.

Science.gov (United States)

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.

Oscillatory activity in neocortical networks during tactile discrimination near the limit of spatial acuity.

Science.gov (United States)

Adhikari, Bhim M; Sathian, K; Epstein, Charles M; Lamichhane, Bidhan; Dhamala, Mukesh

2014-05-01

Oscillatory interactions within functionally specialized but distributed brain regions are believed to be central to perceptual and cognitive functions. Here, using human scalp electroencephalography (EEG) recordings combined with source reconstruction techniques, we study how oscillatory activity functionally organizes different neocortical regions during a tactile discrimination task near the limit of spatial acuity. While undergoing EEG recordings, blindfolded participants felt a linear three-dot array presented electromechanically, under computer control, and reported whether the central dot was offset to the left or right. The average brain response differed significantly for trials with correct and incorrect perceptual responses in the timeframe approximately between 130 and 175ms. During trials with correct responses, source-level peak activity appeared in the left primary somatosensory cortex (SI) at around 45ms, in the right lateral occipital complex (LOC) at 130ms, in the right posterior intraparietal sulcus (pIPS) at 160ms, and finally in the left dorsolateral prefrontal cortex (dlPFC) at 175ms. Spectral interdependency analysis of activity in these nodes showed two distinct distributed networks, a dominantly feedforward network in the beta band (12-30Hz) that included all four nodes and a recurrent network in the gamma band (30-100Hz) that linked SI, pIPS and dlPFC. Measures of network activity in both bands were correlated with the accuracy of task performance. These findings suggest that beta and gamma band oscillatory networks coordinate activity between neocortical regions mediating sensory and cognitive processing to arrive at tactile perceptual decisions. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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…

Other ways of seeing: From behavior to neural mechanisms in the online “visual” control of action with sensory substitution

Science.gov (United States)

Proulx, Michael J.; Gwinnutt, James; Dell’Erba, Sara; Levy-Tzedek, Shelly; de Sousa, Alexandra A.; Brown, David J.

2015-01-01

Vision is the dominant sense for perception-for-action in humans and other higher primates. Advances in sight restoration now utilize the other intact senses to provide information that is normally sensed visually through sensory substitution to replace missing visual information. Sensory substitution devices translate visual information from a sensor, such as a camera or ultrasound device, into a format that the auditory or tactile systems can detect and process, so the visually impaired can see through hearing or touch. Online control of action is essential for many daily tasks such as pointing, grasping and navigating, and adapting to a sensory substitution device successfully requires extensive learning. Here we review the research on sensory substitution for vision restoration in the context of providing the means of online control for action in the blind or blindfolded. It appears that the use of sensory substitution devices utilizes the neural visual system; this suggests the hypothesis that sensory substitution draws on the same underlying mechanisms as unimpaired visual control of action. Here we review the current state of the art for sensory substitution approaches to object recognition, localization, and navigation, and the potential these approaches have for revealing a metamodal behavioral and neural basis for the online control of action. PMID:26599473

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

Directory of Open Access Journals (Sweden)

Shuyang Ding

2017-11-01

Full Text Available 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.

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

Science.gov (United States)

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

Science.gov (United States)

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.

Science.gov (United States)

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.

A silicon-based flexible tactile sensor for ubiquitous robot companion applications

International Nuclear Information System (INIS)

Kim, Kunnyun; Lee, Kang Ryeol; Lee, Dae Sung; Cho, Nam-Kyu; Kim, Won Hyo; Park, Kwang-Bum; Park, Hyo-Derk; Kim, Yong Kook; Park, Yon-Kyu; Kim, Jong-Ho

2006-01-01

We present the fabrication process and characteristics of a 3-axes flexible tactile sensor available for normal and shear mode fabricated using Si micromachining and packaging technologies. The fabrication processes for the 3 axes flexible tactile sensor were classified in the fabrication of sensor chips and their packaging on the flexible PCB. The variation rate of resistance was about 2.1%/N and 0.5%/N in applying normal and shear force, respectively. Because this tactile sensor can measure the variations of resistance of the semiconductor strain gauge for normal and shear force, it can be used to sense touch, pressure, hardness, and slip

Design of a Large-scale Three-dimensional Flexible Arrayed Tactile Sensor

Directory of Open Access Journals (Sweden)

Junxiang Ding

2011-01-01

Full Text Available This paper proposes a new type of large-scale three-dimensional flexible arrayed tactile sensor based on conductive rubber. It can be used to detect three-dimensional force information on the continuous surface of the sensor, which realizes a true skin type tactile sensor. The widely used method of liquid rubber injection molding (LIMS method is used for "the overall injection molding" sample preparation. The structure details of staggered nodes and a new decoupling algorithm of force analysis are given. Simulation results show that the sensor based on this structure can achieve flexible measurement of large-scale 3-D tactile sensor arrays.

Audio-tactile stimulation: A tool to improve health and well-being?

NARCIS (Netherlands)

Dijk, E.O.; Nijholt, A.; Erp, J.B.F. van; Wolferen, G. van; Kuyper, E.

2013-01-01

Stimulation of the tactile sense or the hearing sense can be used to improve a person's health and well-being. For example, to make someone relax, feel better or sleep better. In this position paper, we present the concept of auditory-tactile stimulation for health and well-being. Through carefully

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex.

Science.gov (United States)

Bancroft, Tyler D; Hogeveen, Jeremy; Hockley, William E; Servos, Philip

2014-01-01

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.'s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature.

The motive for sensory pleasure: enjoyment of nature and its representation in painting, music, and literature.

Science.gov (United States)

Eisenberger, Robert; Sucharski, Ivan L; Yalowitz, Steven; Kent, Robert J; Loomis, Ross J; Jones, Jason R; Paylor, Sarah; Aselage, Justin; Mueller, Meta Steiger; McLaughlin, John P

2010-04-01

Eight studies assessed the motive for sensory pleasure (MSP) involving a general disposition to enjoy and pursue pleasant nature-related experiences and avoid unpleasant nature-related experiences. The stated enjoyment of pleasant sights, smells, sounds, and tactile sensations formed a unitary construct that was distinct from sensation seeking, novelty preference, and need for cognition. MSP was found to be related to (a) enjoyment of pleasant nature scenes and music of high but not low clarity; (b) enjoyment of writings that portrayed highly detailed nature scenes; (c) enjoyment of pleasantly themed paintings and dislike of unpleasant paintings, as distinct from findings with Openness to Experience; (d) choice of pleasant nature scenes over exciting or intellectually stimulating scenes; (e) view duration and memory of artistically rendered quilts; (f) interest in detailed information about nature scenes; and (g) frequency of sensory-type suggestions for improvement of a museum exhibit.

The tactile movement aftereffect.

Science.gov (United States)

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

Recruitment of the middle temporal area by tactile motion in congenital blindness

DEFF Research Database (Denmark)

Ptito, Maurice; Matteau, Isabelle; Gjedde, Albert

2009-01-01

We used positron emission tomography to investigate whether tactile motion discrimination activates the dorsal visual stream in congenitally blind (CB) participants compared with sighted controls. The tactile stimuli consisted of either static dots, dots moving coherently in one of two possible...

Direct tactile manipulation of the flight plan in a modern aircraft cockpit

DEFF Research Database (Denmark)

Alapetite, Alexandre; Fogh, Rune; Zammit-Mangion, David

2012-01-01

An original experimental approach has been chosen, with an incremental progression from a traditional physical cockpit, to a tactile flight simulator reproducing traditional controls, to a prototype navigation display with direct tactile functionality, first located in the traditional low position...

Pure Amorphagnosia without Tactile Object Agnosia.

Science.gov (United States)

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.

Generalization of a tactile stimulus in horses.

Science.gov (United States)

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.

Analgesia induced by self-initiated electrotactile sensation is mediated by top-down modulations.

Science.gov (United States)

Zhao, Ke; Tang, Zhengyu; Wang, Huiquan; Guo, Yifei; Peng, Weiwei; Hu, Li

2017-06-01

It is well known that sensory perception can be attenuated when sensory stimuli are controlled by self-initiated actions. This phenomenon is explained by the consistency between forward models of anticipated action effects and actual sensory feedback. Specifically, the brain state related to the binding between motor processing and sensory perception would have inhibitory function by gating sensory information via top-down control. Since the brain state could casually influence the perception of subsequent stimuli of different sensory modalities, we hypothesize that pain evoked by nociceptive stimuli following the self-initiated tactile stimulation would be attenuated as compared to that following externally determined tactile stimulation. Here, we compared psychophysical and neurophysiological responses to identical nociceptive-specific laser stimuli in two different conditions: self-initiated tactile sensation condition (STS) and nonself-initiated tactile sensation condition (N-STS). We observed that pain intensity and unpleasantness, as well as laser-evoked brain responses, were significantly reduced in the STS condition compared to the N-STS condition. In addition, magnitudes of alpha and beta oscillations prior to laser onset were significantly larger in the STS condition than in the N-STS condition. These results confirmed that pain perception and pain-related brain responses were attenuated when the tactile stimulation was initiated by subjects' voluntary actions, and exploited neural oscillations reflecting the binding between motor processing and sensory feedback. Thus, our study elaborated the understanding of underlying neural mechanisms related to top-down modulations of the analgesic effect induced by self-initiated tactile sensation, which provided theoretical basis to improve the analgesic effect in various clinical applications. © 2017 Society for Psychophysiological Research.

Acrolein involvement in sensory and behavioral hypersensitivity following spinal cord injury in the rat

Science.gov (United States)

Zheng, Lingxing; Walls, Michael; Allette, Yohance M.; White, Fletcher A.; Shi, Riyi

2013-01-01

Growing evidence suggests that oxidative stress, as associated with spinal cord injury (SCI), may play a critical role in both neuroinflammation and neuropathic pain conditions. The production of the endogenous aldehyde acrolein, following lipid peroxidation during the inflammatory response, may contribute to peripheral sensitization and hyperreflexia following SCI via the TRPA1-dependent mechanism. Here we report that there are enhanced levels of acrolein and increased neuronal sensitivity to the aldehyde for at least 14 days after SCI. Concurrent with injury-induced increases in acrolein concentration is an increased expression of TRPA1 in the lumbar (L3-L6) sensory ganglia. As proof of the potential pronociceptive role for acrolein, intrathecal injections of acrolein revealed enhanced sensitivity to both tactile and thermal stimuli for up to 10 days, supporting the compound’s pro-nociceptive functionality. Treatment of SCI animals with the acrolein scavenger hydralazine produced moderate improvement in tactile responses as well as robust changes in thermal sensitivity for up to 49 days. Taken together, these data suggests that acrolein directly modulates SCI-associated pain behavior, making it a novel therapeutic target for preclinical and clinical SCI as an analgesic. PMID:24147766

Integration of force reflection with tactile sensing for minimally invasive robotics-assisted tumor localization.

Science.gov (United States)

Talasaz, A; Patel, R V

2013-01-01

Tactile sensing and force reflection have been the subject of considerable research for tumor localization in soft-tissue palpation. The work presented in this paper investigates the relevance of force feedback (presented visually as well as directly) during tactile sensing (presented visually only) for tumor localization using an experimental setup close to one that could be applied for real robotics-assisted minimally invasive surgery. The setup is a teleoperated (master-slave) system facilitated with a state-of-the-art minimally invasive probe with a rigidly mounted tactile sensor at the tip and an externally mounted force sensor at the base of the probe. The objective is to capture the tactile information and measure the interaction forces between the probe and tissue during palpation and to explore how they can be integrated to improve the performance of tumor localization. To quantitatively explore the effect of force feedback on tactile sensing tumor localization, several experiments were conducted by human subjects to locate artificial tumors embedded in the ex vivo bovine livers. The results show that using tactile sensing in a force-controlled environment can realize, on average, 57 percent decrease in the maximum force and 55 percent decrease in the average force applied to tissue while increasing the tumor detection accuracy by up to 50 percent compared to the case of using tactile feedback alone. The results also show that while visual presentation of force feedback gives straightforward quantitative measures, improved performance of tactile sensing tumor localization is achieved at the expense of longer times for the user. Also, the quickness and intuitive data mapping of direct force feedback makes it more appealing to experienced users.

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

Science.gov (United States)

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

Directory of Open Access Journals (Sweden)

Paolo eMotto Ros

2014-04-01

Full Text Available 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 0.7 mm as well as tunable strength of the pins displacement, and refresh rate up to 50 s-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

Continuous theta-burst stimulation modulates tactile synchronization.

Science.gov (United States)

Lee, Kevin Gh; Jacobs, Mark F; Asmussen, Michael J; Zapallow, Christopher M; Tommerdahl, Mark; Nelson, Aimee J

2013-08-23

Temporal order judgement (TOJ) is the ability to detect the order of occurrence of two sequentially delivered stimuli. Previous research has shown that TOJ in the presence of synchronized periodic conditioning stimuli impairs TOJ performance, and this phenomenon is suggested to be mediated by GABAergic interneurons that cause perceptual binding across the two skin sites. Application of continuous theta-burst repetitive TMS (cTBS) over primary somatosensory cortex (SI) alters temporal and spatial tactile perception. The purpose of this study was to examine TOJ perception in the presence and absence of synchronized periodic conditioning stimuli before and after cTBS applied over left-hemisphere SI. A TOJ task was administered on the right index and middle finger (D2 and D3) in two separate sessions in the presence and absence of conditioning stimuli (a background low amplitude sinusoidal vibration). CTBS reduced the impact of the conditioning stimuli on TOJ performance for up to 18 minutes following stimulation while sham cTBS did not affect TOJ performance. In contrast, the TOJ task performed in the absence of synchronized conditioning stimulation was unaltered following cTBS. We conclude that cTBS suppresses inhibitory networks in SI that mediate perceptual binding during TOJ synchronization. CTBS offers one method to suppress cortical excitability in the cortex and potentially benefit clinical populations with altered inhibitory cortical circuits. Additionally, TOJ measures with conditioning stimuli may provide an avenue to assess sensory processing in neurologically impaired patient populations.

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

Science.gov (United States)

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.

Perceptual grouping over time within and across auditory and tactile modalities.

Directory of Open Access Journals (Sweden)

I-Fan Lin

Full Text Available In auditory scene analysis, population separation and temporal coherence have been proposed to explain how auditory features are grouped together and streamed over time. The present study investigated whether these two theories can be applied to tactile streaming and whether temporal coherence theory can be applied to crossmodal streaming. The results show that synchrony detection between two tones/taps at different frequencies/locations became difficult when one of the tones/taps was embedded in a perceptual stream. While the taps applied to the same location were streamed over time, the taps applied to different locations were not. This observation suggests that tactile stream formation can be explained by population-separation theory. On the other hand, temporally coherent auditory stimuli at different frequencies were streamed over time, but temporally coherent tactile stimuli applied to different locations were not. When there was within-modality streaming, temporally coherent auditory stimuli and tactile stimuli were not streamed over time, either. This observation suggests the limitation of temporal coherence theory when it is applied to perceptual grouping over time.

Acoustic Tactile Representation of Visual Information

Science.gov (United States)

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

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

Science.gov (United States)

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.

Guidelines for the use of vibro-tactile displays in human computer interaction

NARCIS (Netherlands)

Erp, J.B.F. van

2002-01-01

Vibro-tactile displays convey messages by presenting vibration to the user's skin. In recent years, the interest in and application of vibro-tactile displays is growing. Vibratory displays are introduced in mobile devices, desktop applications and even in aircraft [1]. Despite the growing interest,

Motion makes sense: an adaptive motor-sensory strategy underlies the perception of object location in rats.

Science.gov (United States)

Saraf-Sinik, Inbar; Assa, Eldad; Ahissar, Ehud

2015-06-10

Tactile perception is obtained by coordinated motor-sensory processes. We studied the processes underlying the perception of object location in freely moving rats. We trained rats to identify the relative location of two vertical poles placed in front of them and measured at high resolution the motor and sensory variables (19 and 2 variables, respectively) associated with this whiskers-based perceptual process. We found that the rats developed stereotypic head and whisker movements to solve this task, in a manner that can be described by several distinct behavioral phases. During two of these phases, the rats' whiskers coded object position by first temporal and then angular coding schemes. We then introduced wind (in two opposite directions) and remeasured their perceptual performance and motor-sensory variables. Our rats continued to perceive object location in a consistent manner under wind perturbations while maintaining all behavioral phases and relatively constant sensory coding. Constant sensory coding was achieved by keeping one group of motor variables (the "controlled variables") constant, despite the perturbing wind, at the cost of strongly modulating another group of motor variables (the "modulated variables"). The controlled variables included coding-relevant variables, such as head azimuth and whisker velocity. These results indicate that consistent perception of location in the rat is obtained actively, via a selective control of perception-relevant motor variables. Copyright © 2015 the authors 0270-6474/15/358777-13$15.00/0.

Repeated touch and needle-prick stimulation in the neonatal period increases the baseline mechanical sensitivity and postinjury hypersensitivity of adult spinal sensory neurons.

Science.gov (United States)

van den Hoogen, Nynke J; Patijn, Jacob; Tibboel, Dick; Joosten, Bert A; Fitzgerald, Maria; Kwok, Charlie H T

2018-03-08

Noxious stimulation at critical stages of development has long-term consequences on somatosensory processing in later life, but it is not known whether this developmental plasticity is restricted to nociceptive pathways. Here, we investigate the effect of repeated neonatal noxious or innocuous hind paw stimulation on adult spinal dorsal horn cutaneous mechanical sensitivity. Neonatal Sprague-Dawley rats of both sexes received 4 unilateral left hind paw needle pricks (NPs, n = 13) or 4 tactile (cotton swab touch) stimuli, per day (TC, n = 11) for the first 7 days of life. Control pups were left undisturbed (n = 17). When adult (6-8 weeks), lumbar wide-dynamic-range neuron activity in laminae III-V was recorded using in vivo extracellular single-unit electrophysiology. Spike activity evoked by cutaneous dynamic tactile (brush), pinch and punctate (von Frey hair) stimulation, and plantar receptive field areas were recorded, at baseline and 2 and 5 days after left plantar hind paw incision. Baseline brush receptive fields, von Frey hair, and pinch sensitivity were significantly enhanced in adult NP and TC animals compared with undisturbed controls, although effects were greatest in NP rats. After incision, injury sensitivity of adult wide-dynamic-range neurons to both noxious and dynamic tactile hypersensitivity was significantly greater in NP animals compared with TC and undisturbed controls. We conclude that both repeated touch and needle-prick stimulation in the neonatal period can alter adult spinal sensory neuron sensitivity to both innocuous and noxious mechanical stimulation. Thus, spinal sensory circuits underlying touch and pain processing are shaped by a range of early-life somatosensory experiences.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Craniosacral therapy as a relaxation method for hyperreactivity in a child with sensory integration disorder – a case report

Directory of Open Access Journals (Sweden)

Katarzyna Strojek

2017-06-01

Full Text Available Impaired sensory processing, the so-called sensory integration disorder, occurs when the brain is unable to correctly process the stimuli coming from the internal and the external environment. Proper sensory integration allows the child for normal everyday functioning (learning, playing, resting, whereas children with impaired sensory integration often lack the psycho-affective balance. They suffer from psychosomatic disorders, which may be caused by e.g. stress due to peer competition at school. Children affected by this disorder need relaxation to regain the balance necessary for proper physical and mental development. The aim of the study is to assess the therapeutic outcomes in a 7-year-old girl diagnosed with vestibular, tactile and proprioceptive deficits. Craniosacral therapy and somatosensory integration method were used. Relaxation therapy had beneficial effects on child’s development, behaviour and the manner of communication with the environment. The hyperesthesia sites, which were present before the therapy, resolved. Previously reported self-aggressive behaviours are no longer observed. Furthermore, the child’s independence, which is crucial for the psychosocial development, also increased during the therapy.

Rectal sensory threshold for pain is a diagnostic marker of irritable bowel syndrome and functional abdominal pain in children.

Science.gov (United States)

Halac, Ugur; Noble, Angela; Faure, Christophe

2010-01-01

To evaluate the diagnostic value of the rectal sensory threshold for pain (RSTP) in children and adolescents with chronic abdominal pain. Fifty-one patients (25 girls; median age 14.2 years; range 8.4-17.6) with abdominal pain >2 months underwent a series of rectal distensions with an electronic barostat. RSTP and viscerosomatic referrals were assessed. Three months after the barostat, the final diagnosis was documented. Thirty-five patients had a functional gastrointestinal disorder (FGID) (irritable bowel syndrome or functional abdominal pain), and 16 had an organic disease. RSTP was lower in the FGID group than in the organic disease group (25.4mm Hg vs 37.1mm Hg; P = .0002). At the cutoff of 30mm Hg, the RSTP measurement for the diagnosis of FGID had a sensitivity of 94% and a specificity of 77%. Both groups similarly reported aberrant viscerosomatic projections. In children, RSTP is a diagnostic marker of irritable bowel syndrome and functional abdominal pain. Viscerosomatic referrals are similar in children with FGID and organic diseases.

Bouba/Kiki in Touch: Associations Between Tactile Perceptual Qualities and Japanese Phonemes

Directory of Open Access Journals (Sweden)

Maki Sakamoto

2018-03-01

Full Text Available Several studies have shown cross-modal associations between sounds and vision or gustation by asking participants to match pre-defined sound-symbolic words (SSWs, such as “bouba” or “kiki,” with visual or gustatory materials. Here, we conducted an explorative study on cross-modal associations of tactile sensations using spontaneous production of Japanese SSWs and semantic ratings. The Japanese language was selected, because it has a large number of SSWs that can represent a wide range of tactile perceptual spaces with fine resolution, and it shows strong associations between sound and touch. In the experiment, we used 120 everyday materials to cover basic material categories that could be associated with fundamental dimensions of tactile perception. Upon contact with these materials, participants expressed their tactile sensations by using Japanese SSWs, and at the same time, evaluated the tactile sensations by semantic differential scales using adjective pairs. Thanks to the variety of testing materials, we were able to demonstrate the existence of systematic associations between sounds and tactile fundamental perceptual dimensions in a more detailed and comprehensive way than ever done so before. In particular, we found that for vowels, positive tactile ratings were associated with the back vowel (/u/, while negative ratings were associated with the front vowels (/i/ and /e/. The central vowels (/o/ and /a/ were mainly associated with rough, hard, and dry feelings. Consonants were categorized based on vocal features and articulation. The category of the voiced consonants (e.g., /dz/ and /g/ corresponded to feelings of roughness, while that of voiceless consonants (e.g., /ʦ/, and /s/ corresponded to feelings of smoothness. The categories of the bilabial plosive (/p/ and /b/ and voiced alveolar nasal (/n/ consonants were mainly related to soft, sticky and wet feelings, while that of voiceless alveolar affricate (/ʦ/ and voiceless velar

Artificial Skin Ridges Enhance Local Tactile Shape Discrimination

Directory of Open Access Journals (Sweden)

Shuzhi Sam Ge

2011-09-01

Full Text Available One of the fundamental requirements for an artificial hand to successfully grasp and manipulate an object is to be able to distinguish different objects’ shapes and, more specifically, the objects’ surface curvatures. In this study, we investigate the possibility of enhancing the curvature detection of embedded tactile sensors by proposing a ridged fingertip structure, simulating human fingerprints. In addition, a curvature detection approach based on machine learning methods is proposed to provide the embedded sensors with the ability to discriminate the surface curvature of different objects. For this purpose, a set of experiments were carried out to collect tactile signals from a 2 × 2 tactile sensor array, then the signals were processed and used for learning algorithms. To achieve the best possible performance for our machine learning approach, three different learning algorithms of Naïve Bayes (NB, Artificial Neural Networks (ANN, and Support Vector Machines (SVM were implemented and compared for various parameters. Finally, the most accurate method was selected to evaluate the proposed skin structure in recognition of three different curvatures. The results showed an accuracy rate of 97.5% in surface curvature discrimination.

Hybrid fabrication process of additive manufacturing and direct writing for a 4 X 4 mm matrix flexible tactile sensor

Energy Technology Data Exchange (ETDEWEB)

Woo, Sang Gu; Lee, In Hwan [Chungbuk National University, Chungju (Korea, Republic of); Lee, Kyong Chang [Pukyong National University, Busan (Korea, Republic of)

2015-09-15

Various machines require data from their external environments for safety and/or accuracy. In this respect, many sensors that mimic the human sensory system have been investigated. Among these, tactile sensors may be useful for obtaining data on the roughness of, and external forces acting upon, an object. Several tactile sensors have been developed; however, these are typically fabricated via a series of complex processes, and hence are unsuitable for volume manufacturing. In this paper, we report a fabrication process for a 4 X 4 mm matrix flexible sensor element using layered manufacturing and direct-write technology. A composite composed of photocurable resin and Multi-walled carbon nanotubes (MWCNTs) was used as the sensing material. The MWCNTs were mixed with the photocurable resin using ultrasonic dispersion, and the liquid mixture exhibited excellent piezoresistive properties following curing using ultraviolet light. The used photocurable resin is flexible and elastic after curing. Therefore, the composite material can be bent and deformed. To use this composite material with the flexible sensor, dispensing characteristics were examined using direct-write technology. For the acquisition of sensor data, a commercial pin-header was inserted and photocurable resin was filled up to the height of pin-header and cured . Then, the composite material was dispensed onto the pin-header as a sensing material. Using this process, a flexible sensor with piezoresistive properties was formed.

Hybrid fabrication process of additive manufacturing and direct writing for a 4 X 4 mm matrix flexible tactile sensor

International Nuclear Information System (INIS)

Woo, Sang Gu; Lee, In Hwan; Lee, Kyong Chang

2015-01-01

Various machines require data from their external environments for safety and/or accuracy. In this respect, many sensors that mimic the human sensory system have been investigated. Among these, tactile sensors may be useful for obtaining data on the roughness of, and external forces acting upon, an object. Several tactile sensors have been developed; however, these are typically fabricated via a series of complex processes, and hence are unsuitable for volume manufacturing. In this paper, we report a fabrication process for a 4 X 4 mm matrix flexible sensor element using layered manufacturing and direct-write technology. A composite composed of photocurable resin and Multi-walled carbon nanotubes (MWCNTs) was used as the sensing material. The MWCNTs were mixed with the photocurable resin using ultrasonic dispersion, and the liquid mixture exhibited excellent piezoresistive properties following curing using ultraviolet light. The used photocurable resin is flexible and elastic after curing. Therefore, the composite material can be bent and deformed. To use this composite material with the flexible sensor, dispensing characteristics were examined using direct-write technology. For the acquisition of sensor data, a commercial pin-header was inserted and photocurable resin was filled up to the height of pin-header and cured . Then, the composite material was dispensed onto the pin-header as a sensing material. Using this process, a flexible sensor with piezoresistive properties was formed.

The Tactile Modality: A Review of Tactile Sensitivity and Human Tactile Interfaces

National Research Council Canada - National Science Library

Myles, Kimberly; Binseel, Mary S

2007-01-01

.... Because humans have a limited capacity to receive, hold in working memory, and cognitively process information taken from the environment, the use of one sensory modality to convey information within...

Pure Amorphagnosia without Tactile Object Agnosia

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Shinichirou Kubota

2017-04-01

Full Text Available 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.

Intuitive tactile algorithms to guide blind runners by means of a belt with vibrators.

Science.gov (United States)

Durá-Gil, Juan V; Bazuelo-Ruiz, Bruno; Mollà, Fernando; Barberà-Guillem, Ricard; Jakab, Àgnes; Csielka, Tamás

2015-01-01

Visually impaired people do not have equal possibilities to practice sports. In the case of running they need a sighted guide. This paper compare different possibilities for indicating direction to blind people by means of a belt that transmits tactile messages, and defines design requirements based on anthropometric analysis. The results shows that intuitive tactile messages are achieved with tactile stimuli applied in the ventral section, from the iliac crests to the navel.

Tactile graphic: the possible form of information and inclusion of the visually impaired

Directory of Open Access Journals (Sweden)

Leia de Andrade

2011-07-01

Full Text Available Although the graphics are present in the textbooks, these are not so accessible to the blind. In this case you need to generate them in high relief to be allowed to read through the tactile sense. For research in the development of tactile graphics with students in 5th grade the urban perimeter of Maringá (PR, drew on the Piaget’s theory, who directed the evaluation of the cognitive development of students in the tasks, and also semiology graphics proposed by Bertin, who helped design treatment information for this production. In order to show the importance of tactile graphics for visually impaired students, which are inserted into the regular classroom, it was evaluated the techniques of construction and production of tactile graphic, and the steps of reading material. The results show that the graphs constructed instigate exploration, as much as it was a favor to tactile perception. It is necessary to respect the "living space" of the chart, in the case indicated by the distance between the hands. Regarding reading, the difficulties encountered were the identification of form, the notion of scale and coordinate system.

Investigating Tactile Stimulation in Symbiotic Systems

DEFF Research Database (Denmark)

Orso, Valeria; Mazza, Renato; Gamberini, Luciano

2017-01-01

The core characteristics of tactile stimuli, i.e., recognition reliability and tolerance to ambient interference, make them an ideal candidate to be integrated into a symbiotic system. The selection of the appropriate stimulation is indeed important in order not to hinder the interaction from...

Bio-inspired grasp control in a robotic hand with massive sensorial input.

Science.gov (United States)

Ascari, Luca; Bertocchi, Ulisse; Corradi, Paolo; Laschi, Cecilia; Dario, Paolo

2009-02-01

The capability of grasping and lifting an object in a suitable, stable and controlled way is an outstanding feature for a robot, and thus far, one of the major problems to be solved in robotics. No robotic tools able to perform an advanced control of the grasp as, for instance, the human hand does, have been demonstrated to date. Due to its capital importance in science and in many applications, namely from biomedics to manufacturing, the issue has been matter of deep scientific investigations in both the field of neurophysiology and robotics. While the former is contributing with a profound understanding of the dynamics of real-time control of the slippage and grasp force in the human hand, the latter tries more and more to reproduce, or take inspiration by, the nature's approach, by means of hardware and software technology. On this regard, one of the major constraints robotics has to overcome is the real-time processing of a large amounts of data generated by the tactile sensors while grasping, which poses serious problems to the available computational power. In this paper a bio-inspired approach to tactile data processing has been followed in order to design and test a hardware-software robotic architecture that works on the parallel processing of a large amount of tactile sensing signals. The working principle of the architecture bases on the cellular nonlinear/neural network (CNN) paradigm, while using both hand shape and spatial-temporal features obtained from an array of microfabricated force sensors, in order to control the sensory-motor coordination of the robotic system. Prototypical grasping tasks were selected to measure the system performances applied to a computer-interfaced robotic hand. Successful grasps of several objects, completely unknown to the robot, e.g. soft and deformable objects like plastic bottles, soft balls, and Japanese tofu, have been demonstrated.

Sensation, mechanoreceptor, and nerve fiber function after nerve regeneration

DEFF Research Database (Denmark)

Krarup, Christian; Rosén, Birgitta; Boeckstyns, Michel

2017-01-01

Objective: Sensation is essential for recovery after peripheral nerve injury. However, the relationship between sensory modalities and function of regenerated fibers is uncertain. We have investigated the relationships between touch threshold, tactile gnosis, and mechanoreceptor and sensory fiber...... function after nerve regeneration. Methods: Twenty-one median or ulnar nerve lesions were repaired by a collagen nerve conduit or direct suture. Quantitative sensory hand function and sensory conduction studies by near-nerve technique, including tactile stimulation of mechanoreceptors, were followed for 2...... years, and results were compared to noninjured hands. Results: At both repair methods, touch thresholds at the finger tips recovered to 81 ± 3% and tactile gnosis only to 20 ± 4% (p nerve action potentials (SNAPs) remained dispersed and areas recovered to 23 ± 2...

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

Science.gov (United States)

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.

The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates

Directory of Open Access Journals (Sweden)

Hui-Xin eQi

2014-05-01

Full Text Available In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b. However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord

Development of a System to Assist Automatic Translation of Hand-Drawn Maps into Tactile Graphics and Its Usability Evaluation

Directory of Open Access Journals (Sweden)

Jianjun Chen

2014-01-01

Full Text Available Tactile graphics are images that use raised surfaces so that a visually impaired person can feel them. Tactile maps are used by blind and partially sighted people when navigating around an environment, and they are also used prior to a visit for orientation purposes. Since the ability to read tactile graphics deeply depends on individuals, providing tactile graphics individually is needed. This implies that producing tactile graphics should be as simple as possible. Based on this background, we are developing a system for automating production of tactile maps from hand-drawn figures. In this paper, we first present a pattern recognition method for hand-drawn maps. The usability of our system is then evaluated by comparing it with the two different methods to produce tactile graphics.

Footwear discrimination using dynamic tactile information

DEFF Research Database (Denmark)

Drimus, Alin; Mikov, Vedran

2017-01-01

Abstract: This paper shows that it is possible to differentiate among various type of footwear solely by using highly dimensional pressure information provided by a sensorised insole. In order to achieve this, a person equipped with two sensorised insoles streaming real-time tactile data to a com...

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies.

Science.gov (United States)

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.

The Psychometric Properties of a New Measure of Sensory Behaviors in Autistic Children

Science.gov (United States)

Neil, Louise; Green, Dido; Pellicano, Elizabeth

2017-01-01

Unusual reactions to sensory input became part of the diagnostic criteria for autism spectrum disorder in the DSM-5. Measures accurately assessing these symptoms are important for clinical decisions. This study examined the reliability and validity of the Sensory Behavior Questionnaire, a parent-report scale designed to assess frequency and impact…

Omega-3 and -6 fatty acid supplementation and sensory processing in toddlers with ASD symptomology born preterm: A randomized controlled trial.

Science.gov (United States)

Boone, Kelly M; Gracious, Barbara; Klebanoff, Mark A; Rogers, Lynette K; Rausch, Joseph; Coury, Daniel L; Keim, Sarah A

2017-12-01

Despite advances in the health and long-term survival of infants born preterm, they continue to face developmental challenges including higher risk for autism spectrum disorder (ASD) and atypical sensory processing patterns. This secondary analysis aimed to describe sensory profiles and explore effects of combined dietary docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and gamma-linolenic acid (GLA) supplementation on parent-reported sensory processing in toddlers born preterm who were exhibiting ASD symptoms. 90-day randomized, double blinded, placebo-controlled trial. 31 children aged 18-38months who were born at ≤29weeks' gestation. Mixed effects regression analyses followed intent to treat and explored effects on parent-reported sensory processing measured by the Infant/Toddler Sensory Profile (ITSP). Baseline ITSP scores reflected atypical sensory processing, with the majority of atypical scores falling below the mean. Sensory processing sections: auditory (above=0%, below=65%), vestibular (above=13%, below=48%), tactile (above=3%, below=35%), oral sensory (above=10%; below=26%), visual (above=10%, below=16%); sensory processing quadrants: low registration (above=3%; below=71%), sensation avoiding (above=3%; below=39%), sensory sensitivity (above=3%; below=35%), and sensation seeking (above=10%; below=19%). Twenty-eight of 31 children randomized had complete outcome data. Although not statistically significant (p=0.13), the magnitude of the effect for reduction in behaviors associated with sensory sensitivity was medium to large (effect size=0.57). No other scales reflected a similar magnitude of effect size (range: 0.10 to 0.32). The findings provide support for larger randomized trials of omega fatty acid supplementation for children at risk of sensory processing difficulties, especially those born preterm. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigating the time course of tactile reflexive attention using a non-spatial discrimination task.

Science.gov (United States)

Miles, Eleanor; Poliakoff, Ellen; Brown, Richard J

2008-06-01

Peripheral cues are thought to facilitate responses to stimuli presented at the same location because they lead to exogenous attention shifts. Facilitation has been observed in numerous studies of visual and auditory attention, but there have been only four demonstrations of tactile facilitation, all in studies with potential confounds. Three studies used a spatial (finger versus thumb) discrimination task, where the cue could have provided a spatial framework that might have assisted the discrimination of subsequent targets presented on the same side as the cue. The final study circumvented this problem by using a non-spatial discrimination; however, the cues were informative and interspersed with visual cues which may have affected the attentional effects observed. In the current study, therefore, we used a non-spatial tactile frequency discrimination task following a non-informative tactile white noise cue. When the target was presented 150 ms after the cue, we observed faster discrimination responses to targets presented on the same side compared to the opposite side as the cue; by 1000 ms, responses were significantly faster to targets presented on the opposite side to the cue. Thus, we demonstrated that tactile attentional facilitation can be observed in a non-spatial discrimination task, under unimodal conditions and with entirely non-predictive cues. Furthermore, we provide the first demonstration of significant tactile facilitation and tactile inhibition of return within a single experiment.

Magnetic Nanocomposite Cilia Tactile Sensor

KAUST Repository

Alfadhel, Ahmed; Kosel, Jü rgen

2015-01-01

A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor's high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

Magnetic Nanocomposite Cilia Tactile Sensor

KAUST Repository

Alfadhel, Ahmed

2015-10-21

A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor\\'s high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

Classification of rigid and deformable objects using a novel tactile sensor

DEFF Research Database (Denmark)

Drimus, Alin; Kootstra, Gert; Bilberg, Arne

2011-01-01

. A real time acquisition system scans the data from the array which is then further processed. We validate the properties of the sensor in an application that classifies a number of household objects while performing a palpation procedure with a robotic gripper. Based on the haptic feedback, we classify......In this paper, we present a novel array tactile sensor for use in robotic grippers based on a flexible piezoresistive rubber. We start by describing the physical principles of piezoresistive materials and continue by outlining how to build a flexible array tactile sensor using stitch electrodes...... the results with the ones obtained from an experimental setup that uses a Weiss Robotics tactile sensor with similar characteristics and we conclude by exemplifying how the results of the classification can be used in different industrial applications....

Investigation of the touch sensitivity of ER fluid based tactile display

Science.gov (United States)

Liu, Yanju; Davidson, Rob; Taylor, Paul

2005-05-01

A tactile display is programmable device whose controlled surface is intended to be investigated by human touch. It has a great number of potential applications in the field of virtual reality and elsewhere. In this research, a 5x5 touch sensitive tactile display array including electrorheological (ER) fluid has been developed and investigated. Experimental results show that the sensed surface information could be controlled effectively by adjusting the voltage activation pattern imposed on the tactels. In the meantime, it is possible to sense the touching force normal to the display"s surface by monitoring the change of current passing through the ER fluid. These encouraging results are helpful for constructing a new type of tactile display based on ER fluid which can act as both sensor and actuator at the same time.

Neonatal Whisker Trimming Impairs Fear/Anxiety-Related Emotional Systems of the Amygdala and Social Behaviors in Adult Mice.

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Hitomi Soumiya

Full Text Available Abnormalities in tactile perception, such as sensory defensiveness, are common features in autism spectrum disorder (ASD. While not a diagnostic criterion for ASD, deficits in tactile perception contribute to the observed lack of social communication skills. However, the influence of tactile perception deficits on the development of social behaviors remains uncertain, as do the effects on neuronal circuits related to the emotional regulation of social interactions. In neonatal rodents, whiskers are the most important tactile apparatus, so bilateral whisker trimming is used as a model of early tactile deprivation. To address the influence of tactile deprivation on adult behavior, we performed bilateral whisker trimming in mice for 10 days after birth (BWT10 mice and examined social behaviors, tactile discrimination, and c-Fos expression, a marker of neural activation, in adults after full whisker regrowth. Adult BWT10 mice exhibited significantly shorter crossable distances in the gap-crossing test than age-matched controls, indicating persistent deficits in whisker-dependent tactile perception. In contrast to controls, BWT10 mice exhibited no preference for the social compartment containing a conspecific in the three-chamber test. Furthermore, the development of amygdala circuitry was severely affected in BWT10 mice. Based on the c-Fos expression pattern, hyperactivity was found in BWT10 amygdala circuits for processing fear/anxiety-related responses to height stress but not in circuits for processing reward stimuli during whisker-dependent cued learning. These results demonstrate that neonatal whisker trimming and concomitant whisker-dependent tactile discrimination impairment severely disturbs the development of amygdala-dependent emotional regulation.

Sensorial saturation for infants' pain.

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Bellieni, Carlo Valerio; Tei, Monica; Coccina, Francesca; Buonocore, Giuseppe

2012-04-01

Sensorial saturation (SS) is a multisensorial stimulation consisting of delicate tactile, gustative, auditory and visual stimuli. This procedure consists of simultaneously: attracting the infant's attention by massaging the infant's face; speaking to the infant gently, but firmly, and instilling a sweet solution on the infant's tongue. We performed a systematic Medline search of for articles focusing on human neonatal studies related to SS. The search was performed within the last 10 years and was current as of January 2012. We retrieved 8 articles that used a complete form of SS and 2 articles with an incomplete SS. Data show that the use of SS is effective in relieving newborns' pain. Oral solution alone are less effective than SS, but the stimuli without oral sweet solution are ineffective. the partial forms of SS have some effectiveness, but minor than the complete SS. Only one article showed lack of SS as analgesic method, after endotracheal suctioning. SS can be used for all newborns undergoing blood samples or other minor painful procedures. It is more effective than oral sugar alone. SS also promotes interaction between nurse and infant and is a simple effective form of analgesia for the neonatal intensive care unit.

Cross-Modal Correspondences Enhance Performance on a Colour-to-Sound Sensory Substitution Device.

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Hamilton-Fletcher, Giles; Wright, Thomas D; Ward, Jamie

Visual sensory substitution devices (SSDs) can represent visual characteristics through distinct patterns of sound, allowing a visually impaired user access to visual information. Previous SSDs have avoided colour and when they do encode colour, have assigned sounds to colour in a largely unprincipled way. This study introduces a new tablet-based SSD termed the ‘Creole’ (so called because it combines tactile scanning with image sonification) and a new algorithm for converting colour to sound that is based on established cross-modal correspondences (intuitive mappings between different sensory dimensions). To test the utility of correspondences, we examined the colour–sound associative memory and object recognition abilities of sighted users who had their device either coded in line with or opposite to sound–colour correspondences. Improved colour memory and reduced colour-errors were made by users who had the correspondence-based mappings. Interestingly, the colour–sound mappings that provided the highest improvements during the associative memory task also saw the greatest gains for recognising realistic objects that also featured these colours, indicating a transfer of abilities from memory to recognition. These users were also marginally better at matching sounds to images varying in luminance, even though luminance was coded identically across the different versions of the device. These findings are discussed with relevance for both colour and correspondences for sensory substitution use.

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

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Calogero Maria Oddo

2009-04-01

Full Text Available A compliant 2x2 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.

RETENTION OF HIGH TACTILE ACUITY THROUGHOUT THE LIFESPAN IN BLINDNESS

OpenAIRE

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

2008-01-01

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 test...

Symbol recognition produced by points of tactile stimulation: the illusion of linear continuity.

Science.gov (United States)

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.

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

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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

Assessment of rival males through the use of multiple sensory cues in the fruitfly Drosophila pseudoobscura.

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Chris P Maguire

Full Text Available Environments vary stochastically, and animals need to behave in ways that best fit the conditions in which they find themselves. The social environment is particularly variable, and responding appropriately to it can be vital for an animal's success. However, cues of social environment are not always reliable, and animals may need to balance accuracy against the risk of failing to respond if local conditions or interfering signals prevent them detecting a cue. Recent work has shown that many male Drosophila fruit flies respond to the presence of rival males, and that these responses increase their success in acquiring mates and fathering offspring. In Drosophila melanogaster males detect rivals using auditory, tactile and olfactory cues. However, males fail to respond to rivals if any two of these senses are not functioning: a single cue is not enough to produce a response. Here we examined cue use in the detection of rival males in a distantly related Drosophila species, D. pseudoobscura, where auditory, olfactory, tactile and visual cues were manipulated to assess the importance of each sensory cue singly and in combination. In contrast to D. melanogaster, male D. pseudoobscura require intact olfactory and tactile cues to respond to rivals. Visual cues were not important for detecting rival D. pseudoobscura, while results on auditory cues appeared puzzling. This difference in cue use in two species in the same genus suggests that cue use is evolutionarily labile, and may evolve in response to ecological or life history differences between species.

[Advances in the research of function of Merkel cells in tactile formation of skin].

Science.gov (United States)

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.

An Outdoor Navigation System for Blind Pedestrians Using GPS and Tactile-Foot Feedback

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Ramiro Velázquez

2018-04-01

Full Text Available This paper presents a novel, wearable navigation system for visually impaired and blind pedestrians that combines a global positioning system (GPS for user outdoor localization and tactile-foot stimulation for information presentation. Real-time GPS data provided by a smartphone are processed by dedicated navigation software to determine the directions to a destination. Navigational directions are then encoded as vibrations and conveyed to the user via a tactile display that inserts into the shoe. The experimental results showed that users were capable of recognizing with high accuracy the tactile feedback provided to their feet. The preliminary tests conducted in outdoor locations involved two blind users who were guided along 380–420 m predetermined pathways, while sharing the space with other pedestrians and facing typical urban obstacles. The subjects successfully reached the target destinations. The results suggest that the proposed system enhances independent, safe navigation of blind pedestrians and show the potential of tactile-foot stimulation in assistive devices.

Shared Neural Mechanisms for the Evaluation of Intense Sensory Stimulation and Economic Reward, Dependent on Stimulation-Seeking Behavior.

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Norbury, Agnes; Valton, Vincent; Rees, Geraint; Roiser, Jonathan P; Husain, Masud

2016-09-28

Why are some people strongly motivated by intense sensory experiences? Here we investigated how people encode the value of an intense sensory experience compared with economic reward, and how this varies according to stimulation-seeking preference. Specifically, we used a novel behavioral task in combination with computational modeling to derive the value individuals assigned to the opportunity to experience an intense tactile stimulus (mild electric shock). We then examined functional imaging data recorded during task performance to see how the opportunity to experience the sensory stimulus was encoded in stimulation-seekers versus stimulation-avoiders. We found that for individuals who positively sought out this kind of sensory stimulation, there was common encoding of anticipated economic and sensory rewards in the ventromedial prefrontal cortex. Conversely, there was robust encoding of the modeled probability of receiving such stimulation in the insula only in stimulation-avoidant individuals. Finally, we found preliminary evidence that sensory prediction error signals may be positively signed for stimulation-seekers, but negatively signed for stimulation-avoiders, in the posterior cingulate cortex. These findings may help explain why high intensity sensory experiences are appetitive for some individuals, but not for others, and may have relevance for the increased vulnerability for some psychopathologies, but perhaps increased resilience for others, in high sensation-seeking individuals. People vary in their preference for intense sensory experiences. Here, we investigated how different individuals evaluate the prospect of an unusual sensory experience (electric shock), compared with the opportunity to gain a more traditional reward (money). We found that in a subset of individuals who sought out such unusual sensory stimulation, anticipation of the sensory outcome was encoded in the same way as that of monetary gain, in the ventromedial prefrontal cortex

Practice makes perfect: the neural substrates of tactile discrimination by Mah-Jong experts include the primary visual cortex

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Honda Manabu

2006-12-01

Full Text Available Abstract Background It has yet to be determined whether visual-tactile cross-modal plasticity due to visual deprivation, particularly in the primary visual cortex (V1, is solely due to visual deprivation or if it is a result of long-term tactile training. Here we conducted an fMRI study with normally-sighted participants who had undergone long-term training on the tactile shape discrimination of the two dimensional (2D shapes on Mah-Jong tiles (Mah-Jong experts. Eight Mah-Jong experts and twelve healthy volunteers who were naïve to Mah-Jong performed a tactile shape matching task using Mah-Jong tiles with no visual input. Furthermore, seven out of eight experts performed a tactile shape matching task with unfamiliar 2D Braille characters. Results When participants performed tactile discrimination of Mah-Jong tiles, the left lateral occipital cortex (LO and V1 were activated in the well-trained subjects. In the naïve subjects, the LO was activated but V1 was not activated. Both the LO and V1 of the well-trained subjects were activated during Braille tactile discrimination tasks. Conclusion The activation of V1 in subjects trained in tactile discrimination may represent altered cross-modal responses as a result of long-term training.

Movement Induces the Use of External Spatial Coordinates for Tactile Localization in Congenitally Blind Humans.

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Heed, Tobias; Möller, Johanna; Röder, Brigitte

2015-01-01

To localize touch, the brain integrates spatial information coded in anatomically based and external spatial reference frames. Sighted humans, by default, use both reference frames in tactile localization. In contrast, congenitally blind individuals have been reported to rely exclusively on anatomical coordinates, suggesting a crucial role of the visual system for tactile spatial processing. We tested whether the use of external spatial information in touch can, alternatively, be induced by a movement context. Sighted and congenitally blind humans performed a tactile temporal order judgment task that indexes the use of external coordinates for tactile localization, while they executed bimanual arm movements with uncrossed and crossed start and end postures. In the sighted, start posture and planned end posture of the arm movement modulated tactile localization for stimuli presented before and during movement, indicating automatic, external recoding of touch. Contrary to previous findings, tactile localization of congenitally blind participants, too, was affected by external coordinates, though only for stimuli presented before movement start. Furthermore, only the movement's start posture, but not the planned end posture affected blind individuals' tactile performance. Thus, integration of external coordinates in touch is established without vision, though more selectively than when vision has developed normally, and possibly restricted to movement contexts. The lack of modulation by the planned posture in congenitally blind participants suggests that external coordinates in this group are not mediated by motor efference copy. Instead the task-related frequent posture changes, that is, movement consequences rather than planning, appear to have induced their use of external coordinates.

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

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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.

A novel flexible tactile sensor based on Ce-doped BaTiO3 nanofibers

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Zhuang, Yongyong; Xu, Zhuo; Fu, Xiaotian; Li, Fei; Li, Jinglei; Liao, Zhipeng; Liu, Weihua

2017-07-01

The performance of a robotic hand is severely limited by the tactile feedback information similar to a human hand. Hence, a novel and robust tactile sensor has been developed to cope with the challenge of robotic hand technology. Piezoelectric material is proposed as a suitable candidate for a new efficient tactile sensor due to its excellent piezoelectric properties. In this paper, a novel flexible tactile sensor based on Ce-doped BTO nanofibers was developed. The doping mechanism of cerium ions and the working process of the sensor were analysed. The results showed that sheer stress had no contribution to the sensor, this indicated that the sensor was easy to control according to the individual’s wish. The output voltage of the sensor could reach up to 0.078 V which showed great potential for the future of intelligent robot skin application.

Unmyelinated Tactile Cutaneous Nerves Signal Erotic Sensations

NARCIS (Netherlands)

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

IntroductionIntrapersonal 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

Visual and tactile interfaces for bi-directional human robot communication

Science.gov (United States)

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.

Sensing through friction: the biomechanics of texture perception in rodents and primates

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Debrégeas, Georges; Boubenec, Yves

2015-10-01

Rodents and primates possess an exquisite tactile sensitivity, which allows them to extract a wealth of information about their immediate environment. They can distinguish subtle differences in surface roughness through tactile exploration in a much more precise way than they can do visually. In both sensory systems, tactile information is contained in the sequence of deformation of the tactile organ--the facial hair for rodents (the whiskers), the digital skin for primates -- elicited by active rubbing on the probed surface (Figure 8.1). These deformations, registered by mechanosensitive neurons located in inner tissues, are processed by the central nervous system to produce a sensory representation of the surface...

High Resolution Tactile Sensors for Curved Robotic Fingertips

DEFF Research Database (Denmark)

Drimus, Alin; Jankovics, Vince; Gorsic, Matija

2014-01-01

Tactile sensing is a key element for various animals that interact with the environment and surrounding objects. Touch provides information about contact forces, torques and pressure distribution and by the means of exploration it provides object properties such as geometry, stiffness and texture...... trivial to obtain, dealing with limited accuracy, occlusions and calibration problems. In terms of sensors for static stimuli, such as pressure, there are a range of technologies that can be used to manufacture transducers with various results[5].......Tactile sensing is a key element for various animals that interact with the environment and surrounding objects. Touch provides information about contact forces, torques and pressure distribution and by the means of exploration it provides object properties such as geometry, stiffness and texture[5...

Weber's Illusion and Body Shape: Anisotropy of Tactile Size Perception on the Hand

Science.gov (United States)

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…

Spatial Asynchronous Visuo-Tactile Stimuli influence Ownership of Virtual Wings

DEFF Research Database (Denmark)

Andreasen, Anastassia; Nilsson, Niels Chr.; Serafin, Stefania

2018-01-01

This poster describes a within-subject study of the virtual body ownership (VBO) illusion using anatomically similar but morphologically different body of a virtual bat. Participants experienced visuo-tactile stimulation of their arms while seeing an object touching the wing of the bat. The mapping...... between the real and the virtual touch points varied across three conditions: no spatial deviation between visual and tactile input, 50% deviation, and 70% deviation. The results suggest that the degree of experienced VBO varies across the conditions. The illusion was broken in the absence of visuo...

Object texture recognition by dynamic tactile sensing using active exploration

DEFF Research Database (Denmark)

Drimus, Alin; Børlum Petersen, Mikkel; Bilberg, Arne

with a dynamic tactile transducer based on polyvinylidene fluoride (PVDF) piezoelectric film. Different test surfaces are actively explored and the signal from the sensor is used for feature extraction, which is subsequently used for classification. A comparison between the significance of different extracted......For both humans and robots, tactile sensing is important for interaction with the environment: it is the core sensing used for exploration and manipulation of objects. In this paper, we present a method for determining object texture by active exploration with a robotic fingertip equipped...

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

International Nuclear Information System (INIS)

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

2014-01-01

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. (papers)

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

Science.gov (United States)

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.

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

Science.gov (United States)

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

2016-02-01

Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

The Invisible Universe: A Tactile and Braille Exhibit of Astronomical Images

Science.gov (United States)

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.

Evaluation of Circle Diameter by Distributed Tactile Information in Active Tracing

Directory of Open Access Journals (Sweden)

Hiroyuki Nakamoto

2013-01-01

Full Text Available Active touch with voluntary movement on the surface of an object is important for human to obtain the local and detailed features on it. In addition, the active touch is considered to enhance the human spatial resolution. In order to improve dexterity performance of multifinger robotic hands, it is necessary to study an active touch method for robotic hands. In this paper, first, we define four requirements of a tactile sensor for active touch and design a distributed tactile sensor model, which can measure a distribution of compressive deformation. Second, we suggest a measurement process with the sensor model, a synthesis method of distributed deformations. In the experiments, a five-finger robotic hand with tactile sensors traces on the surface of cylindrical objects and evaluates the diameters. We confirm that the hand can obtain more information of the diameters by tracing the finger.

Arborealities: The Tactile Ecology of Hardy’s Woodlanders

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William A. Cohen

2014-10-01

Full Text Available This article asks what consequences two recent movements in scholarship - affect theory and environmental studies - might have for understanding the Victorian tactile imagination. Thomas Hardy's 1887 novel 'The Woodlanders' provides a means of addressing this question, for it shares with posthumanist critics a view that people are material things in a world of things, and that the world is itself a collection of vital agencies and networked actors. Hardy shows how a tactile modality provides a point of entry into discussions of both affect and ecology, situating the human in a proximate, contiguous relation to both bodily and environmental materialities. 'The Woodlanders' offers a world in which trees, in particular, work on - and are in turn worked on by - human objects; a world in which, one might say, the trees are people and the people are trees. This arboreality is far from a sentimental oneness with nature, nor is it an exercise in anthropomorphization. Instead, it provides a recognition of the inhuman, material, and sensate aspects of the human; or, perhaps better, of the human as rooted, budding, leafy, and abloom. Like some recent theoretical accounts, 'The Woodlanders' disperses agency among human and non-human elements alike, employing a tactile mode of representation to break down distinctions between them. Normal 0 false false false EN-US X-NONE X-NONE

Tactile spatial resolution in blind braille readers.

Science.gov (United States)

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.

Play with your food! Sensory play is associated with tasting of fruits and vegetables in preschool children.

Science.gov (United States)

Coulthard, Helen; Sealy, Annemarie

2017-06-01

The objective of the current study was to ascertain whether taking part in a sensory play activity with real fruits and vegetables (FV) can encourage tasting in preschool children, compared to a non-food activity or visual exposure to the activity. Three to four year old pre-school children (N = 62) were recruited from three preschool nursery classes from a school in Northamptonshire, UK. A between participants experimental study was conducted with each class assigned to one of three conditions; sensory FV play, sensory non-food play and visual FV exposure. Parental report of several baseline variables were taken; child baseline liking of the foods used in the study, parental and child FV consumption (portions/day), child neophobia and child tactile sensitivity. Outcome measures were the number of fruits and vegetables tasted in a post experiment taste test which featured (n = 5) or did not feature (n = 3) in the task. Analyses of covariance controlling for food neophobia and baseline liking of foods, showed that after the activity children in the sensory FV play condition tried more FV than both children in the non-food sensory play task (p foods used in the activity (p foods that were not used in the activity (p vegetables may encourage FV tasting in preschool children more than non food play or visual exposure alone. Long term intervention studies need to be carried out to see if these effects can be sustained over time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Research progress of functional magnetic resonance imaging in cross-modal activation of visual cortex during tactile perception

International Nuclear Information System (INIS)

Zhan Jie; Gong Honghan

2013-01-01

An increasing amount of neuroimaging studies recently demonstrated activation of visual cortex in both blind and sighted participants when performing a variety of tactile tasks such as Braille reading and tactile object recognition, which indicates that visual cortex not only receives visual information, but may participate in tactile perception. To address these cross-modal changes of visual cortex and the neurophysiological mechanisms, many researchers conducted explosive studies using functional magnetic resonance imaging (fMRI) and have made some achievements. This review focuses on cross-modal activation of visual cortex and the underlying mechanisms during tactile perception in both blind and sighted individuals. (authors)

The Tactile Ethics of Soft Robotics: Designing Wisely for Human-Robot Interaction.

Science.gov (United States)

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.

Perception-Based Tactile Soft Keyboard for the Touchscreen of Tablets

Directory of Open Access Journals (Sweden)

Kwangtaek Kim

2018-01-01

Full Text Available Most mobile devices equipped with touchscreens provide on-screen soft keyboard as an input method. However, many users are experiencing discomfort due to lack of physical feedback that causes slow typing speed and error-prone typing, as compared to the physical keyboard. To solve the problem, a platform-independent haptic soft keyboard suitable for tablet-sized touchscreens was proposed and developed. The platform-independent haptic soft keyboard was verified on both Android and Windows. In addition, a psychophysical experiment has been conducted to find an optimal strength of key click feedback on touchscreens, and the perception result was applied for making uniform tactile forces on touchscreens. The developed haptic soft keyboard can be easily integrated with existing tablets by putting the least amount of effort. The evaluation results confirm platform independency, fast tactile key click feedback, and uniform tactile force distribution on touchscreen with using only two piezoelectric actuators. The proposed system was developed on a commercial tablet (Mu Pad that has dual platforms (Android and Windows.

[Hereditary motor and sensory neuropathy type 4A].

Science.gov (United States)

Shagina, O A; Dadali, E L; Fedotov, V P; Tiburkova, T B; Poliakov, A V

2010-01-01

The first in the Russian Federation clinical cases of patients with autosomal-recessive type of hereditary motor and sensory neuropathy, type 4A, (HMSN 4A) are presented. In all cases, the diagnosis has been verified using molecular-genetic methods (DNA diagnostics). An analysis of features of clinical manifestations was performed in patients, aged from 5 to 34 years, with different disease duration (from 3-to 29 years). Criteria of selection of patients for DNA diagnostics for searching mutations in the GDAP1 gene are specified.

Compact Tactile Sensors for Robot Fingers

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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.

Vertically stacked nanocellulose tactile sensor.

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Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun

2017-11-16

Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10 4 loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

3D capacitive tactile sensor using DRIE micromachining

Science.gov (United States)

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.

Evidence for embodied predictive coding: the anterior insula coordinates cortical processing of tactile deviancy

DEFF Research Database (Denmark)

Allen, Micah; Fardo, Francesca; Dietz, Martin

2015-01-01

this possibility in the somatosensory domain, we measured brain activity using functional magnetic resonance imaging while healthy participants discriminated tactile stimuli in a roving oddball design. Dynamic Causal Modelling revealed that unexpected stimuli increased the strength of forward connections...... processing of tactile changes to support body awareness....

Stereo camera based virtual cane system with identifiable distance tactile feedback for the blind.

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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.

Short-term memory for spatial configurations in the tactile modality: a comparison with vision.

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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.

Tactile object familiarity in the blind brain reveals the supramodal perceptual-mnemonic nature of the perirhinal cortex

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Laura eCacciamani

2016-04-01

Full Text Available 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 subjects 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. 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.

Tecnologia tátil para a avaliação da dor em cegos Tecnología táctil para la evaluación del dolor en ciegos Tactile technology for pain evaluation in blind people

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Ana Cláudia de Souza Toniolli

2003-03-01

Full Text Available Trata-se de um estudo descritivo e exploratório das percepções dos cegos acerca do protótipo chamado Escala Tátil, para avaliação da intensidade da dor. Por meio de uma entrevista semi-estruturada, foram obtidos os relatos de cegos da Associação dos Cegos do Ceará, para descrever a natureza do protótipo, estabelecendo relações entre as suas experiências dolorosas e buscando significados para a sua utilização na cultura dos cegos. Dos relatos, foram identificados e analisados três temas: intensidade da dor na ponta dos dedos, percepção da escala tátil da dor, destacando-se textura, forma e tamanho, lapidando-se a Escala Tátil. A percepção sensorial tátil dos cegos gerou novos parâmetros de reflexão para o estudo da dor e direcionou a performance do protótipo para um processo de comunicação da dor mais satisfatório.Este es un estudio descriptivo de las percepciones de los ciegos acerca del prototipo llamado Escala Táctil para evaluación de la intensidad del dolor. A través de una entrevista semi-estructurada, se obtuvieron relatos de ciegos de la Asociación del Ciegos de la ciudad de Ceará-BR para describir la naturaleza del prototipo, estableciendo relaciones entre sus experiencias dolorosas y buscando significados para su utilización en la cultura de los ciegos. De los relatos fueron identificados y analizados tres temas: intensidad del dolor en la punta de los dedos, percepción de la escala táctil del dolor: textura, forma y tamaño y puliendo la Escala Táctil. La percepción sensorial de las personas ciegas generó nuevos parámetros de reflexión para el estudio del dolor y orientó la performance del prototipo hacia un proceso de comunicación del dolor más satisfactorio.This is a descriptive study of blind people perceptions about a prototype called Tactile Scale for pain intensity evaluation. By means of a half-structured interview, reports were collected from blind people from the Ceará Blind

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

Science.gov (United States)

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.

A delivery device for presentation of tactile stimuli during functional magnetic resonance imaging.

Science.gov (United States)

Dykes, Robert W; Miqueé, Aline; Xerri, Christian; Zennou-Azogui, Yoh'i; Rainville, Constant; Dumoulin, André; Marineau, Daniel

2007-01-30

We describe a novel stimulus delivery system designed to present tactile stimuli to a subject in the tunnel of a magnetic resonance imaging (MRI) system. Using energy from an air-driven piston to turn a wheel, the device advances a conveyor belt with a pre-determined sequence of stimuli that differ in their spatial features into the tunnel of the MRI. The positioning of one or several stimulus objects in a window near the subject's hand is controlled by a photoelectric device that detects periodic openings in the conveyor belt. Using this electric signal to position each presentation avoids cumulative positioning errors and provides a signal related to the progression of the experiment. We used a series of shapes that differed in their spatial features but the device could carry stimuli with a diversity of shapes and textures. This flexibility allows the experimenter to design a wide variety of psychophysical experiments in the haptic world and possibly to compare and contrast these stimuli with the cognitive treatment of similar stimuli delivered to the other senses. Appropriate experimental design allows separation of motor, sensory and memory storage phases of mental processes.

Cortical processing of tactile stimuli applied in quick succession across the fingertips: temporal evolution of dipole sources revealed by magnetoencephalography.

Science.gov (United States)

Karageorgiou, Elissaios; Koutlas, Ioannis G; Alonso, Aurelio A; Leuthold, Arthur C; Lewis, Scott M; Georgopoulos, Apostolos P

2008-08-01

We used magnetoencephalography (MEG) in 10 healthy human subjects to study cortical responses to tactile stimuli applied to the fingertips of digits 2-5 of the right hand. Each stimulus lasted 50 ms and was produced by air-driven elastic membranes. Four-hundred stimuli were delivered on each finger in three temporal patterns (conditions). In the "Discrete" condition, stimuli were applied to each finger repetitively with an interstimulus interval (ISI) of 1-2 s. In the "Continuous" condition, stimuli were applied to the fingers sequentially as four-stimulus trains with zero ISI and 1-2 s intervening between trains. Finally, in the "Gap" condition, stimuli were applied as in the Continuous condition but with an ISI of 50 ms. A sensation of tactile motion across fingers (digit 2 --> digit 5) was reported by all subjects in the Continuous and Gap conditions. Cortical responses were extracted as single equivalent current dipoles over a period of 1 s following stimulus onset. In all three conditions, initial responses in left primary somatosensory cortex (SI) were observed ~20 to 50 ms after stimulus onset and were followed by additional left SI responses and bilateral responses in the secondary somatosensory cortex (SII). In addition, in the Continuous and Gap conditions, there was an activation of the precentral gyrus, the temporal aspects of which depended on the temporal relation of the administered stimuli, as follows. An ISI of 0 ms led to activation of the precentral gyrus shortly after the second stimulation, whereas an ISI of 50 ms led to activation of the precentral gyrus after the third stimulation. The current findings support results from previous studies on temporal activity patterns in SI and SII, verify the participation of the precentral gyrus during tactile motion perception and, in addition, reveal aspects of integration of sequential sensory stimulations over nonadjacent areas as well as temporal activity patterns in the postcentral and precentral

Can you see what you feel? Color and folding properties affect visual-tactile material discrimination of fabrics.

Science.gov (United States)

Xiao, Bei; Bi, Wenyan; Jia, Xiaodan; Wei, Hanhan; Adelson, Edward H

2016-01-01

Humans can often estimate tactile properties of objects from vision alone. For example, during online shopping, we can often infer material properties of clothing from images and judge how the material would feel against our skin. What visual information is important for tactile perception? Previous studies in material perception have focused on measuring surface appearance, such as gloss and roughness, and using verbal reports of material attributes and categories. However, in real life, predicting tactile properties of an object might not require accurate verbal descriptions of its surface attributes or categories. In this paper, we use tactile perception as ground truth to measure visual material perception. Using fabrics as our stimuli, we measure how observers match what they see (photographs of fabric samples) with what they feel (physical fabric samples). The data shows that color has a significant main effect in that removing color significantly reduces accuracy, especially when the images contain 3-D folds. We also find that images of draped fabrics, which revealed 3-D shape information, achieved better matching accuracy than images with flattened fabrics. The data shows a strong interaction between color and folding conditions on matching accuracy, suggesting that, in 3-D folding conditions, the visual system takes advantage of chromatic gradients to infer tactile properties but not in flattened conditions. Together, using a visual-tactile matching task, we show that humans use folding and color information in matching the visual and tactile properties of fabrics.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

KAUST Repository

Alfadhel, Ahmed; Khan, Mohammed Zahed Mustafa; Cardoso, Susana; Leitao, Diana; Kosel, Jü rgen

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.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

KAUST Repository

Alfadhel, Ahmed

2016-05-07

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.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

Directory of Open Access Journals (Sweden)

Ahmed Alfadhel

2016-05-01

Full Text Available 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.

Noise Enhances Action Potential Generation in Mouse Sensory Neurons via Stochastic Resonance.

Science.gov (United States)

Onorato, Irene; D'Alessandro, Giuseppina; Di Castro, Maria Amalia; Renzi, Massimiliano; Dobrowolny, Gabriella; Musarò, Antonio; Salvetti, Marco; Limatola, Cristina; Crisanti, Andrea; Grassi, Francesca

2016-01-01

Noise can enhance perception of tactile and proprioceptive stimuli by stochastic resonance processes. However, the mechanisms underlying this general phenomenon remain to be characterized. Here we studied how externally applied noise influences action potential firing in mouse primary sensory neurons of dorsal root ganglia, modelling a basic process in sensory perception. Since noisy mechanical stimuli may cause stochastic fluctuations in receptor potential, we examined the effects of sub-threshold depolarizing current steps with superimposed random fluctuations. We performed whole cell patch clamp recordings in cultured neurons of mouse dorsal root ganglia. Noise was added either before and during the step, or during the depolarizing step only, to focus onto the specific effects of external noise on action potential generation. In both cases, step + noise stimuli triggered significantly more action potentials than steps alone. The normalized power norm had a clear peak at intermediate noise levels, demonstrating that the phenomenon is driven by stochastic resonance. Spikes evoked in step + noise trials occur earlier and show faster rise time as compared to the occasional ones elicited by steps alone. These data suggest that external noise enhances, via stochastic resonance, the recruitment of transient voltage-gated Na channels, responsible for action potential firing in response to rapid step-wise depolarizing currents.

Neurosurgical tactile discrimination training with haptic-based virtual reality simulation.

Science.gov (United States)

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.

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

Science.gov (United States)

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

2016-02-01

Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Transfer of tactile perceptual learning to untrained neighboring fingers reflects natural use relationships.

Science.gov (United States)

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.

The influence of tactile cognitive maps on auditory space perception in sighted persons.

Directory of Open Access Journals (Sweden)

Alessia Tonelli

2016-11-01

Full Text Available 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

Stereo Camera Based Virtual Cane System with Identifiable Distance Tactile Feedback for the Blind

Directory of Open Access Journals (Sweden)

Donghun Kim

2014-06-01

Full Text Available 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.

Endogenous Sensory Discrimination and Selection by a Fast Brain Switch for a High Transfer Rate Brain-Computer Interface.

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Xu, Ren; Jiang, Ning; Dosen, Strahinja; Lin, Chuang; Mrachacz-Kersting, Natalie; Dremstrup, Kim; Farina, Dario

2016-08-01

In this study, we present a novel multi-class brain-computer interface (BCI) for communication and control. In this system, the information processing is shared by the algorithm (computer) and the user (human). Specifically, an electro-tactile cycle was presented to the user, providing the choice (class) by delivering timely sensory input. The user discriminated these choices by his/her endogenous sensory ability and selected the desired choice with an intuitive motor task. This selection was detected by a fast brain switch based on real-time detection of movement-related cortical potentials from scalp EEG. We demonstrated the feasibility of such a system with a four-class BCI, yielding a true positive rate of  ∼ 80% and  ∼ 70%, and an information transfer rate of  ∼ 7 bits/min and  ∼ 5 bits/min, for the movement and imagination selection command, respectively. Furthermore, when the system was extended to eight classes, the throughput of the system was improved, demonstrating the capability of accommodating a large number of classes. Combining the endogenous sensory discrimination with the fast brain switch, the proposed system could be an effective, multi-class, gaze-independent BCI system for communication and control applications.

5G-Enabled Tactile Internet

OpenAIRE

Simsek, Meryem; Aijaz, Adnan; Dohler, Mischa; Sachs, Joachim; Fettweis, Gerhard

2016-01-01

The long-term ambition of the Tactile Internet is to enable a democratization of skill, and how it is being delivered globally. An integral part of this is to be able to transmit touch in perceived real-time, which is enabled by suitable robotics and haptics equipment at the edges, along with an unprecedented communications network. The fifth generation (5G) mobile communications systems will underpin this emerging Internet at the wireless edge. This paper presents the most important technolo...

Cassini Scientist for a Day: a tactile experience

Science.gov (United States)

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

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Okafor Olubukola O

2010-04-01

Full Text Available Abstract 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.

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

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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.

Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal).

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Schmid, Anne-Christine; Chien, Jui-Hong; Greenspan, Joel D; Garonzik, Ira; Weiss, Nirit; Ohara, Shinji; Lenz, Frederick Arthur

2016-06-01

The normal organization and plasticity of the cutaneous core of the thalamic principal somatosensory nucleus (ventral caudal, Vc) have been studied by single-neuron recordings and microstimulation in patients undergoing awake stereotactic operations for essential tremor (ET) without apparent somatic sensory abnormality and in patients with dystonia or chronic pain secondary to major nervous system injury. In patients with ET, most Vc neurons responded to one of the four stimuli, each of which optimally activates one mechanoreceptor type. Sensations evoked by microstimulation were similar to those evoked by the optimal stimulus only among rapidly adapting neurons. In patients with ET, Vc was highly segmented somatotopically, and vibration, movement, pressure, and sharp sensations were usually evoked by microstimulation at separate sites in Vc. In patients with conditions including spinal cord transection, amputation, or dystonia, RFs were mismatched with projected fields more commonly than in patients with ET. The representation of the border of the anesthetic area (e.g., stump) or of the dystonic limb was much larger than that of the same part of the body in patients with ET. This review describes the organization and reorganization of human Vc neuronal activity in nervous system injury and dystonia and then proposes basic mechanisms. Copyright © 2016 the American Physiological Society.

Remotely deployable aerial inspection using tactile sensors

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MacLeod, C. N.; Cao, J.; Pierce, S. G.; Sullivan, J. C.; Pipe, A. G.; Dobie, G.; Summan, R.

2014-02-01

For structural monitoring applications, the use of remotely deployable Non-Destructive Evaluation (NDE) inspection platforms offer many advantages, including improved accessibility, greater safety and reduced cost, when compared to traditional manual inspection techniques. The use of such platforms, previously reported by researchers at the University Strathclyde facilitates the potential for rapid scanning of large areas and volumes in hazardous locations. A common problem for both manual and remote deployment approaches lies in the intrinsic stand-off and surface coupling issues of typical NDE probes. The associated complications of these requirements are obviously significantly exacerbated when considering aerial based remote inspection and deployment, resulting in simple visual techniques being the preferred sensor payload. Researchers at Bristol Robotics Laboratory have developed biomimetic tactile sensors modelled on the facial whiskers (vibrissae) of animals such as rats and mice, with the latest sensors actively sweeping their tips across the surface in a back and forth motion. The current work reports on the design and performance of an aerial inspection platform and the suitability of tactile whisking sensors to aerial based surface monitoring applications.

Diagnostic Statistical Manual 5 Changes to the Autism Diagnostic Criteria: A Critical Moment for Occupational Therapists

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Rondalyn Varney Whitney Ph.D., OT/L

2012-11-01

Full Text Available Changes in the soon to be released Diagnostic Statistical Manual (DSM – 5 (American Psychiatric Association, 2012 bring new opportunities for occupational therapy, but the profession must prepare for the impact these changes forecast. While well positioned to capitalize on newly defined specifications of Autism Spectrum Disorders (ASD and the elevation of sensory processing difficulties to a core feature of the disorder, the profession must be alert to the potential downside of the pending changes. The more stringentdiagnostic rubric will likely exclude a significant number of individuals currently eligible for therapeutic and academic services. Autism will be defined as a neurodevelopmental disorder that must be identifiable before early childhood (age 5, even if it is not detected until later as a result of environmental factors (minimal social demands, support from caretakers, etc.. The new diagnostic criteria will add the explicit recognition of sensory behaviors within a subdomain of stereotyped motor, verbal, and sensory-based behaviors and researchers suggest only 60% of those who currently meet the threshold for an autism spectrum diagnosis will continue to meet criteria under the new categorization. The proposed changes will likely encourage researchers to use greater specificity when recruiting sample populations and, as a result, help to determine interventions that are most advantageous for specific subtypes. Addressing sensory processing in thediagnostic criteria may authorize interventions aimed specifically towards reduction of sensory-related disabilities through remediation, environmental support, or parent education while simultaneously calling upon us to deliver evidence for Ayres’ sensory integration® (ASI approaches. The change also presents anurgent call to our profession to promote the unique scientific contributions occupational therapy makes for individuals with ASD, their families, and their educational contexts

Integration of anatomical and external response mappings explains crossing effects in tactile localization: A probabilistic modeling approach.

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Badde, Stephanie; Heed, Tobias; Röder, Brigitte

2016-04-01

To act upon a tactile stimulus its original skin-based, anatomical spatial code has to be transformed into an external, posture-dependent reference frame, a process known as tactile remapping. When the limbs are crossed, anatomical and external location codes are in conflict, leading to a decline in tactile localization accuracy. It is unknown whether this impairment originates from the integration of the resulting external localization response with the original, anatomical one or from a failure of tactile remapping in crossed postures. We fitted probabilistic models based on these diverging accounts to the data from three tactile localization experiments. Hand crossing disturbed tactile left-right location choices in all experiments. Furthermore, the size of these crossing effects was modulated by stimulus configuration and task instructions. The best model accounted for these results by integration of the external response mapping with the original, anatomical one, while applying identical integration weights for uncrossed and crossed postures. Thus, the model explained the data without assuming failures of remapping. Moreover, performance differences across tasks were accounted for by non-individual parameter adjustments, indicating that individual participants' task adaptation results from one common functional mechanism. These results suggest that remapping is an automatic and accurate process, and that the observed localization impairments in touch result from a cognitively controlled integration process that combines anatomically and externally coded responses.

A Ventral Visual Stream Reading Center Independent of Sensory Modality and Visual Experience

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Lior Reich

2011-10-01

Full Text Available The Visual Word Form Area (VWFA is a ventral-temporal-visual area that develops expertise for visual reading. It encodes letter-strings irrespective of case, font, or location in the visual-field, with striking anatomical reproducibility across individuals. In the blind, reading can be achieved using Braille, with a comparable level-of-expertise to that of sighted readers. We investigated which area plays the role of the VWFA in the blind. One would expect it to be at either parietal or bilateral occipital cortex, reflecting the tactile nature of the task and crossmodal plasticity, respectively. However, according to the notion that brain areas are task specific rather than sensory-modality specific, we predicted recruitment of the left-hemispheric VWFA, identically to the sighted and independent of visual experience. Using fMRI we showed that activation during Braille reading in congenitally blind individuals peaked in the VWFA, with striking anatomical consistency within and between blind and sighted. The VWFA was reading-selective when contrasted to high-level language and low-level sensory controls. Further preliminary results show that the VWFA is selectively activated also when people learn to read in a new language or using a different modality. Thus, the VWFA is a mutlisensory area specialized for reading regardless of visual experience.

When touch matters: an affective tactile intervention for older adults.

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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.

Development of tactile floor plan for the blind and the visually impaired by 3D printing technique

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Raša Urbas

2016-07-01

Full Text Available The aim of the research was to produce tactile floor plans for blind and visually impaired people for the use in the museum. For the production of tactile floor plans 3D printing technique was selected among three different techniques. 3D prints were made of white and colored ABS polymer materials. Development of different elements of tactile floor plans, as well as the problems and the solutions during 3D printing, are described in the paper.

The Design of a Novel Flexible Tactile Sensor Based on Pressure-conductive Rubber

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Fei Xu

2011-01-01

Full Text Available A novel flexible tactile sensor using conductive rubber with electrical-wires knitted method is presented. The sensor’s design is based on rubber’s pressure-sensitive property. It is flexible and can be mounted on any object to measure tactile information. The mathematic piezoresistivity model of the rubber is described, and we also discuss the sensor’s structure and scanning method. The simulation results show that the sensor can detect pressure accurately.

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

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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.

Tactile massage and hypnosis as a health promotion for nurses in emergency care-a qualitative study

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Nordby-Hörnell Elisabeth

2011-10-01

Full Text Available Abstract Background This study explores nursing personnel's experiences and perceptions of receiving tactile massage and hypnosis during a personnel health promotion project. Nursing in a short term emergency ward environment can be emotionally and physically exhausting due to the stressful work environment and the high dependency patient care. A health promotion project integrating tactile massage and hypnosis with conventional physical activities was therefore introduced for nursing personnel working in this setting at a large university hospital in Sweden. Methods Four semi-structured focus group discussions were conducted with volunteer nursing personnel participants after the health promotion project had been completed. There were 16 participants in the focus groups and there were 57 in the health promotion intervention. The discussions were transcribed verbatim and analysed with qualitative content analysis. Results The findings indicated that tactile massage and hypnosis may contribute to reduced levels of stress and pain and increase work ability for some nursing personnel. The sense of well-being obtained in relation to health promotion intervention with tactile massage and hypnosis seemed to have positive implications for both work and leisure. Self-awareness, contentment and self-control may be contributing factors related to engaging in tactile massage and hypnosis that might help nursing personnel understand their patients and colleagues and helped them deal with difficult situations that occurred during their working hours. Conclusion The findings indicate that the integration of tactile massage and hypnosis in personnel health promotion may be valuable stress management options in addition to conventional physical activities.

Development of flexible tactile sensors for hexapod robots

DEFF Research Database (Denmark)

Drimus, Alin; Børlum-Petersen, Mikkel; Jouffroy, Jerome

2013-01-01

This paper describes the development of flexible based tactile array sensors based on piezoresistive rubber for use in the leg tips of hexapod robotics. The sensors are composed of a sandwich similar structure, with a piezoresistive rubber used as the middle layer and flexPCB electrodes...

Comparative evaluation of audio and audio - tactile methods to improve oral hygiene status of visually impaired school children

OpenAIRE

R Krishnakumar; Swarna Swathi Silla; Sugumaran K Durai; Mohan Govindarajan; Syed Shaheed Ahamed; Logeshwari Mathivanan

2016-01-01

Background: Visually impaired children are unable to maintain good oral hygiene, as their tactile abilities are often underdeveloped owing to their visual disturbances. Conventional brushing techniques are often poorly comprehended by these children and hence, it was decided to evaluate the effectiveness of audio and audio-tactile methods in improving the oral hygiene of these children. Objective: To evaluate and compare the effectiveness of audio and audio-tactile methods in improving oral h...

The relationship between sensory processing and anxiety on cars scale in autism spectrum disorder

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Novaković Neda

2015-01-01

Full Text Available Autism Spectrum Disorder is a neurodevelopmental disorder, characterized by deficits in social interactions, social communication, stereotyped behavior associated with sensory disorders occurring before the age of 3. There has been a growing trend of this neurodevelopmental disorder in recent years. Although the sensory processing problems have been noticed since the first descriptions of autism spectrum disorders, it is only the DSM-5, diagnostic and statistical manual of mental disorders, that includes sensory problems, as the crucial symptom in diagnostic profile of autism spectrum disorder. Objective: To establish the relationship between functional areas related to sensory processing and anxiety, as well as to determine the degree of autistic disorder in adolescents and adults with autism spectrum disorder. Method: 42 participants, adolescents and adults with severe autism disorder and intellectual disability, aged 15-35, of both sexes from Belgrade were evaluated by Childhood Autism Rating Scale (CARS used to determine the degree of autistic disorder. The following functional areas were compared: sensory interests and anxiety in adolescents and adults with autistic spectrum of both sexes. Results: The results indicated the existence of the relationship between anxiety and unusual sensory interests and the severity of autism spectrum disorder. The results showed that there was a correlation between visual perception and the level of intellectual functioning, especially of the severity of autistic disorder and visual perception. Conclusion: These results indicate the reasons of the problems and difficulties in the field of general adaptation of the individuals with autism spectrum disorder.

Attending to and remembering tactile stimuli: a review of brain imaging data and single-neuron responses.

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Burton, H; Sinclair, R J

2000-11-01

Clinical and neuroimaging observations of the cortical network implicated in tactile attention have identified foci in parietal somatosensory, posterior parietal, and superior frontal locations. Tasks involving intentional hand-arm movements activate similar or nearby parietal and frontal foci. Visual spatial attention tasks and deliberate visuomotor behavior also activate overlapping posterior parietal and frontal foci. Studies in the visual and somatosensory systems thus support a proposal that attention to the spatial location of an object engages cortical regions responsible for the same coordinate referents used for guiding purposeful motor behavior. Tactile attention also biases processing in the somatosensory cortex through amplification of responses to relevant features of selected stimuli. Psychophysical studies demonstrate retention gradients for tactile stimuli like those reported for visual and auditory stimuli, and suggest analogous neural mechanisms for working memory across modalities. Neuroimaging studies in humans using memory tasks, and anatomic studies in monkeys support the idea that tactile information relayed from the somatosensory cortex is directed ventrally through the insula to the frontal cortex for short-term retention and to structures of the medial temporal lobe for long-term encoding. At the level of single neurons, tactile (such as visual and auditory) short-term memory appears as a persistent response during delay intervals between sampled stimuli.

Variation in rhinarium temperature indicates sensory specializations in placental mammals.