RESUMEN
The influence of extrinsic hand-feel touch cues on consumer experiences in food and beverage consumption is well established. However, their impact on trigeminal perception, particularly the oral irritation caused by capsaicin or spicy foods, is less understood. This study aimed to determine the existence of cross-modal associations between hand-feel touch and capsaicin-induced oral irritation. This study investigated whether these potential associations were driven by the sensory contributions of the hand-feel tactile materials (measured by instrumental physical parameters) or by affective responses (evaluated through hedonic scales and the self-reported emotion questionnaire, EsSense Profile®, by consumers). In our study, 96 participants tasted a capsaicin solution while engaging with nine hand-feel tactile materials, i.e., cardboard, linen, rattan, silicone, stainless steel, sandpaper (fine), sandpaper (rough), sponge, and towel. They subsequently rated their liking and emotional responses, perceived intensity of oral irritation, and the congruency between hand-feel tactile sensation and oral irritation. Instrumental measurements characterized the surface texture of the hand-feel tactile materials, which were correlated with the collected sensory data. The results revealed that unique cross-modal associations between hand-feel touch and capsaicin-induced oral irritation. Specifically, while sandpapers demonstrated high congruence with the sensation of oral irritation, stainless steel was found to be least congruent. These associations were influenced by both the common emotional responses ("active," "aggressive," "daring," "energetic," "guilty," and "worried") evoked by the hand-feel tactile materials and the capsaicin, as well as by participants' liking for the hand-feel tactile materials and the characteristics of the surface textures. This study provides empirical evidence of the cross-modality between hand-feel tactile sensations and capsaicin-induced oral irritation, opening new avenues for future research in this area.
Asunto(s)
Capsaicina , Tacto , Humanos , Capsaicina/efectos adversos , Femenino , Masculino , Adulto , Adulto Joven , Mano , Gusto , Adolescente , Emociones , Percepción del Tacto , Persona de Mediana EdadRESUMEN
Several gaps persist in haptic device development due to the multifaceted nature of the sense of touch. Existing gaps include challenges enhancing touch feedback fidelity, providing diverse haptic sensations, and ensuring wearability for delivering tactile stimuli to the fingertips. Here, we introduce the Bioinspired Adaptable Multiplanar Haptic system, offering mechanotactile/steady and vibrotactile pulse stimuli with adjustable intensity (up to 298.1 mN) and frequencies (up to 130 Hz). This system can deliver simultaneous stimuli across multiple fingertip areas. The paper includes a full characterisation of our system. As the device can play an important role in further understanding human touch, we performed human stimuli sensitivity and differentiation experiments to evaluate the capability of delivering mechano-vibrotactile, variable intensity, simultaneous, multiplanar and operator agnostic stimuli. Our system promises to accelerate the development of touch perception devices, providing painless, operator-independent data crucial for researching and diagnosing touch-related disorders.
Asunto(s)
Percepción del Tacto , Tacto , Vibración , Humanos , Tacto/fisiología , Percepción del Tacto/fisiología , Dedos/fisiología , Adulto , Masculino , Femenino , Estimulación Física , Diseño de Equipo , Adulto JovenRESUMEN
Computer haptics (CH) is about integration of tactile sensation and rendering in Metaverse. However, unlike computer vision (CV) where both hardware infrastructure and software programs are well developed, a generic tactile data capturing device that serves the same role as what a camera does for CV, is missing. Bioinspired by electrophysiological processes in human tactile somatosensory nervous system, here we propose a tactile scanner along with a neuromorphically-engineered system, in which a closed-loop tactile acquisition and rendering (re-creation) are preliminarily achieved. Based on the architecture of afferent nerves and intelligent functions of mechano-gating and leaky integrate-and-fire models, such a tactile scanner is designed and developed by using piezoelectric transducers as axon neurons and thin film transistor (TFT)-based neuromorphic circuits to mimic synaptic behaviours and neural functions. As an example, the neuron-like tactile information of surface textures is captured and further used to render the texture friction of a virtual surface for "recreating" a "true" feeling of touch.
Asunto(s)
Tacto , Humanos , Tacto/fisiología , Percepción del Tacto/fisiología , Neuronas/fisiología , Axones/fisiologíaRESUMEN
BACKGROUND: Planning and executing movements requires the integration of different sensory modalities, such as vision and proprioception. However, neurological diseases like stroke can lead to full or partial loss of proprioception, resulting in impaired movements. Recent advances focused on providing additional sensory feedback to patients to compensate for the sensory loss, proving vibrotactile stimulation to be a viable option as it is inexpensive and easy to implement. Here, we test how such vibrotactile information can be integrated with visual signals to estimate the spatial location of a reach target. METHODS: We used a center-out reach paradigm with 31 healthy human participants to investigate how artificial vibrotactile stimulation can be integrated with visual-spatial cues indicating target location. Specifically, we provided multisite vibrotactile stimulation to the moving dominant arm using eccentric rotating mass (ERM) motors. As the integration of inputs across multiple sensory modalities becomes especially relevant when one of them is uncertain, we additionally modulated the reliability of visual cues. We then compared the weighing of vibrotactile and visual inputs as a function of visual uncertainty to predictions from the maximum likelihood estimation (MLE) framework to decide if participants achieve quasi-optimal integration. RESULTS: Our results show that participants could estimate target locations based on vibrotactile instructions. After short training, combined visual and vibrotactile cues led to higher hit rates and reduced reach errors when visual cues were uncertain. Additionally, we observed lower reaction times in trials with low visual uncertainty when vibrotactile stimulation was present. Using MLE predictions, we found that integration of vibrotactile and visual cues followed optimal integration when vibrotactile cues required the detection of one or two active motors. However, if estimating the location of a target required discriminating the intensities of two cues, integration violated MLE predictions. CONCLUSION: We conclude that participants can quickly learn to integrate visual and artificial vibrotactile information. Therefore, using additional vibrotactile stimulation may serve as a promising way to improve rehabilitation or the control of prosthetic devices by patients suffering loss of proprioception.
Asunto(s)
Señales (Psicología) , Desempeño Psicomotor , Vibración , Percepción Visual , Humanos , Masculino , Femenino , Adulto , Percepción Visual/fisiología , Desempeño Psicomotor/fisiología , Adulto Joven , Retroalimentación Sensorial/fisiología , Propiocepción/fisiología , Percepción del Tacto/fisiología , Incertidumbre , Estimulación Física/métodos , Percepción Espacial/fisiología , Movimiento/fisiologíaRESUMEN
BACKGROUND: Problem-solving and learning in mathematics involves sensory perception and processing. Multisensory integration may contribute by enhancing sensory estimates. This study aims to assess if combining visual and somatosensory information improves elementary students' perimeter and area estimates. METHODS: 87 4th graders compared rectangles with respect to area or perimeter either solely using visual observation or additionally with somatosensory information. Three experiments targeted different task aspects. Statistical analyses tested success rates and response times. RESULTS: Contrary to expectations, adding somatosensory information did not boost success rates for area and perimeter comparison. Response time even increased with adding somatosensory information. Children's difficulty in accurately tracing figures negatively impacted the success rate of area comparisons. DISCUSSION: Results suggest visual observation alone suffices for accurately estimating and comparing area and perimeter of rectangles in 4th graders. IMPLICATIONS: Careful deliberation on the inclusion of somatosensory information in mathematical tasks concerning perimeter and area estimations of rectangles is recommended.
Asunto(s)
Matemática , Tiempo de Reacción , Instituciones Académicas , Percepción Visual , Humanos , Niño , Femenino , Masculino , Tiempo de Reacción/fisiología , Percepción Visual/fisiología , Solución de Problemas , Aprendizaje/fisiología , Percepción del Tacto/fisiologíaRESUMEN
Classic attachment theory emphasizes the sensitivity of the parent to perceive and appropriately respond to the infant's cues. However, parent-child attachment is a dyadic interaction that is also dependent upon the sensitivity of the child to the early caregiving environment. Individual differences in infant sensitivity to parental cues is likely shaped by both the early caregiving environment as well as the infant's neurobiology, such as perceptual sensitivity to social stimuli. Here, we investigated associations between maternal postpartum depression and infant neurological sensitivity to affective touch using brain signal entropy - a metric of the brain's moment-to-moment variability related to signal processing. We recruited two independent samples of infants aged 0-5 months. In Sample 1 (n = 79), we found increased levels of maternal postpartum depression were associated with diminished perceptual sensitivity - i.e. lower entropy - to affective tactile stimulation specifically within the primary somatosensory cortex. In Sample 2 (n = 36), we replicated this finding and showed that this effect was not related to characteristics of the touch administered during the experiment. These results suggest that decreased affective touch early in life - a common consequence of postpartum depression - likely impacts the infant's perceptual sensitivity to affective touch and ultimately the formation of experience-dependent neural networks that support the successful formation of attachment relationships.
Asunto(s)
Depresión Posparto , Relaciones Madre-Hijo , Tacto , Humanos , Femenino , Depresión Posparto/psicología , Lactante , Masculino , Adulto , Relaciones Madre-Hijo/psicología , Tacto/fisiología , Recién Nacido , Afecto/fisiología , Percepción del Tacto/fisiología , Apego a Objetos , Corteza Somatosensorial/fisiología , Corteza Somatosensorial/fisiopatología , Encéfalo , Madres/psicología , ElectroencefalografíaRESUMEN
As robots are increasingly participating in our daily lives, the quests to mimic human abilities have driven the advancements of robotic multimodal senses. However, current perceptual technologies still unsatisfied robotic needs for home tasks/environments, particularly facing great challenges in multisensory integration and fusion, rapid response capability, and highly sensitive perception. Here, we report a flexible tactile sensor utilizing thin-film thermistors to implement multimodal perceptions of pressure, temperature, matter thermal property, texture, and slippage. Notably, the tactile sensor is endowed with an ultrasensitive (0.05 mm/s) and ultrafast (4 ms) slip sensing that is indispensable for dexterous and reliable grasping control to avoid crushing fragile objects or dropping slippery objects. We further propose and develop a robotic tactile-visual fusion architecture that seamlessly encompasses multimodal sensations from the bottom level to robotic decision-making at the top level. A series of intelligent grasping strategies with rapid slip feedback control and a tactile-visual fusion recognition strategy ensure dexterous robotic grasping and accurate recognition of daily objects, handling various challenging tasks, for instance grabbing a paper cup containing liquid. Furthermore, we showcase a robotic desktop-cleaning task, the robot autonomously accomplishes multi-item sorting and cleaning desktop, demonstrating its promising potential for smart housekeeping.
Asunto(s)
Robótica , Tacto , Robótica/instrumentación , Robótica/métodos , Humanos , Tacto/fisiología , Fuerza de la Mano/fisiología , Diseño de Equipo , Percepción del Tacto/fisiologíaRESUMEN
Existing maze apparatuses used in rodents often exclusively assess spatial discriminability as a means to evaluate learning impairments. Spatial learning in such paradigms is reportedly spared by moderate prenatal alcohol exposure in rats, suggesting that spatial reinforcement alone is insufficient to delineate executive dysfunction, which consistently manifests in humans prenatally-exposed to alcohol. To address this, we designed a single-session continuous performance task in the T-maze apparatus that requires rats to discriminate within and between simultaneously-presented spatial (left or right) and tactile (sandpaper or smooth) stimuli for food reinforcement across four sequential discrimination stages: simple discrimination, intradimensional reversal 1, extradimensional shift, and intradimensional reversal 2. This design incorporates elements of working memory, attention, and goal-seeking behavior which collectively contribute to the executive function construct. Here, we found that rats prenatally-exposed to alcohol performed worse in both the tactile intradimensional reversal and extradimensional shift; alternatively, rats prenatally-exposed to alcohol acquired the extradimensional shift faster when shifting from the tactile to spatial dimension. In line with previous work, moderate prenatal alcohol exposure spared specifically spatial discrimination in this paradigm. However, when tactile stimuli were mapped into the spatial dimension, rats prenatally-exposed to alcohol required more trials to discriminate between the dimensions. We demonstrate that tactile stimuli can be operantly employed in a continuous performance T-maze task to detect discriminatory learning impairments in rats exposed to moderate prenatal alcohol. The current paradigm may be useful for assessing features of executive dysfunction in rodent models of fetal alcohol spectrum disorders.
Asunto(s)
Etanol , Aprendizaje por Laberinto , Efectos Tardíos de la Exposición Prenatal , Animales , Embarazo , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Femenino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Etanol/farmacología , Etanol/administración & dosificación , Etanol/efectos adversos , Masculino , Ratas , Ratas Long-Evans , Percepción Espacial/efectos de los fármacos , Percepción Espacial/fisiología , Discriminación en Psicología/efectos de los fármacos , Discriminación en Psicología/fisiología , Percepción del Tacto/fisiología , Percepción del Tacto/efectos de los fármacos , Memoria a Corto Plazo/efectos de los fármacos , Memoria a Corto Plazo/fisiología , Trastornos del Espectro Alcohólico Fetal/fisiopatología , Tacto/fisiología , Tacto/efectos de los fármacosRESUMEN
Integrating tactile feedback through haptic interfaces enhances experiences in virtual and augmented reality. However, electrotactile systems, which stimulate mechanoreceptors directly, often yield inconsistent tactile results due to variations in pressure between the device and the finger. In this study, we present the integration of a transparent electrotactile screen with pressure-sensitive transistors, ensuring highly consistent quantitative haptic sensations. These transistors effectively calibrate tactile variations caused by touch pressure. Additionally, we explore remote-distance tactile stimulations achieved through the interference of electromagnetic waves. We validated tactile perception using somatosensory evoked potentials, monitoring the somatosensory cortex response. Our haptic screen can stimulate diverse electrotactile sensations and demonstrate various tactile patterns, including Morse code and Braille, when integrated with portable smart devices, delivering a more immersive experience. Furthermore, interference of electric fields allows haptic stimulation to facilitate diverse stimulus positioning at lower current densities, extending the reach beyond direct contact with electrodes of our screen.
Asunto(s)
Potenciales Evocados Somatosensoriales , Percepción del Tacto , Tacto , Transistores Electrónicos , Humanos , Potenciales Evocados Somatosensoriales/fisiología , Masculino , Percepción del Tacto/fisiología , Tacto/fisiología , Femenino , Adulto , Corteza Somatosensorial/fisiología , Presión , Dedos/fisiología , Adulto Joven , Mecanorreceptores/fisiología , Retroalimentación Sensorial/fisiologíaRESUMEN
When we interact with objects using our hands, we derive their size through our skin. Prolonged exposure to an object leads to a perceptual size aftereffect: adapting to a larger/smaller object makes a subsequently perceived object to appear smaller/larger than its actual size. This phenomenon has been described as haptic as tactile sensations with kinesthetic feedback are involved. However, the exact role of different haptic components in generating this aftereffect remains largely underexplored. Here, we investigated how different aspects of haptic touch influence size perception. After adaptation to a large sphere with one hand and a small sphere with the other, participants touched two test spheres of equal or different sizes and judged which one felt larger. Similar haptic size adaption aftereffects were observed (a) when participants repeatedly grasped on and off the adapters, (b) when they simply continued to grasp the adapters without further hand movements, and (c) when the adapters were grasped without involving the fingers. All these conditions produced stronger aftereffects than a condition where the palms were simply resting on the adapter. Our findings suggest that the inclusion of grasp markedly increased the aftereffects, highlighting the pivotal role of haptic interactions in determining perceptual size adaptation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
Asunto(s)
Mano , Percepción del Tamaño , Percepción del Tacto , Humanos , Adulto , Percepción del Tacto/fisiología , Adulto Joven , Percepción del Tamaño/fisiología , Masculino , Femenino , Mano/fisiología , Adaptación Fisiológica/fisiología , Desempeño Psicomotor/fisiologíaRESUMEN
The enfacement illusion is a facial version of the rubber hand illusion, in which participants experience tactile stimulation of their own faces synchronously with the observation of the same stimulation applied to another's face. In previous studies, participants have reported experiencing an illusory embodiment of the other's face following synchronous compared to asynchronous stimulation. In a series of three experiments, we addressed the following three questions: (i) how does similarity between the self and the other, operationalized here as being of the same or different gender to the other, impact the experience of embodiment in the enfacement illusion; (ii) does the experience of embodiment result from alterations to the self-concept; and (iii) is susceptibility to the experience of embodiment associated with interoceptive processing, i.e. perception of the internal state of the body? Results indicate that embodiment is facilitated by the similarity between the self and the other and is mediated by the incorporation of the other into the self-concept, but sensitivity to one's own internal states does not impact upon embodiment within the enfacement illusion. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.
Asunto(s)
Ilusiones , Autoimagen , Percepción del Tacto , Humanos , Masculino , Femenino , Adulto , Adulto Joven , Percepción del Tacto/fisiología , Cara , AdolescenteRESUMEN
BACKGROUND: The study of tactile perception during a childhood is extremely important for understanding the social and communicative aspects of the child's development. Tactile perception of stimuli with different valence can have different normative stages of development. METHODS: In the present study, we examined changes in linear and nonlinear electroencephalogram (EEG) parameters during the presentation of pleasant (C-tactile optimal stroking), unpleasant (ice stroking), and neutral tactile stimuli in three groups of healthy volunteers: preschoolers 4 and 5 years, school-age children from 8 to 10 years, and adults from 20 to 40 years. RESULTS: According to our findings, child maturation plays a significant role in the perception of pleasant and neutral tactile stimuli. Patterns of EEG dynamics related to tactile perception showed greater similarity between adult volunteers and school-aged children than preschoolers. CONCLUSIONS: Non-linear EEG parameters such as fractal dimension (FD), envelope mean frequency (EMF), and power spectral density (PSD) dynamics of the theta-rhythm were particularly sensitive to developmental changes in tactile perception. Hjorth complexity and peak alpha frequency (PAF) scores may serve as indicators of mature perception of С-tactile (CT)-stimuli.
Asunto(s)
Electroencefalografía , Percepción del Tacto , Humanos , Percepción del Tacto/fisiología , Preescolar , Masculino , Femenino , Niño , Adulto , Adulto Joven , Encéfalo/fisiología , Estimulación Física , Desarrollo Infantil/fisiología , Factores de Edad , Emociones/fisiologíaRESUMEN
The sense of touch is a property that allows humans to interact delicately with their physical environment. This article reports on a technological advancement in intuitive human-robot interaction that enables an intrinsic robotic sense of touch without the use of artificial skin or tactile instrumentation. On the basis of high-resolution joint-force-torque sensing in a redundant arrangement, we were able to let the robot sensitively feel the surrounding environment and accurately localize touch trajectories in space and time that were applied on its surface by a human. Through an intertwined combination of manifold learning techniques and artificial neural networks, the robot identified and interpreted those touch trajectories as machine-readable letters, symbols, or numbers. This opens up unexplored opportunities in terms of intuitive and flexible interaction between human and robot. Furthermore, we showed that our concept of so-called virtual buttons can be used to straightforwardly implement a tactile communication link, including switches and slider bars, which are complementary to speech, hardware buttons, and control panels. These interaction elements could be freely placed, moved, and configured in arbitrary locations on the robot structure. The intrinsic sense of touch we proposed in this work can serve as the basis for an advanced category of physical human-robot interaction that has not been possible yet, enabling a shift from conventional modalities toward adaptability, flexibility, and intuitive handling.
Asunto(s)
Sistemas Hombre-Máquina , Redes Neurales de la Computación , Robótica , Tacto , Robótica/instrumentación , Humanos , Tacto/fisiología , Diseño de Equipo , Intuición , Interfaz Usuario-Computador , Percepción del Tacto/fisiología , TorqueRESUMEN
In tactile sensing, decoding the journey from afferent tactile signals to efferent motor commands is a significant challenge primarily due to the difficulty in capturing population-level afferent nerve signals during active touch. This study integrates a finite element hand model with a neural dynamic model by using microneurography data to predict neural responses based on contact biomechanics and membrane transduction dynamics. This research focuses specifically on tactile sensation and its direct translation into motor actions. Evaluations of muscle synergy during in -vivo experiments revealed transduction functions linking tactile signals and muscle activation. These functions suggest similar sensorimotor strategies for grasping influenced by object size and weight. The decoded transduction mechanism was validated by restoring human-like sensorimotor performance on a tendon-driven biomimetic hand. This research advances our understanding of translating tactile sensation into motor actions, offering valuable insights into prosthetic design, robotics, and the development of next-generation prosthetics with neuromorphic tactile feedback.
Asunto(s)
Tacto , Humanos , Tacto/fisiología , Mano/fisiología , Fenómenos Biomecánicos , Fuerza de la Mano/fisiología , Percepción del Tacto/fisiología , Músculo Esquelético/fisiología , Retroalimentación Sensorial/fisiología , Modelos Neurológicos , Robótica , MasculinoRESUMEN
Tactile and pain perception are essential for biological skin to interact with the external environment. This complex interplay of sensations allows for the detection of potential threats and appropriate responses to stimuli. However, the challenge is to enable flexible electronics to respond to mechanical stimuli such as biological skin, and researchers have not clearly reported the successful integration of somatic mechanical perception and sensation management functions into neuro-like electronics. In this work, an afferent nerve-like device with a pressure sensor and a perception management module is proposed. The pressure sensor comprises two conductive fabric layers and an ionic hydrogel, forming a capacitor structure that emulates the swift transition from tactile to pain perception under mechanical stimulation. Drawing inspiration from the neuronal "gate control" mechanism, the sensation management module adjusts signals in response to rubbing, accelerating the discharge process and reducing the perception duration, thereby replicating the inhibitory effect of biological neurons on pain following tactile interference. This integrated device, encompassing somatic mechanical perception and sensation management, holds promise for applications in soft robotics, prosthetics, and human-machine interaction.
Asunto(s)
Técnicas Biosensibles , Diseño de Equipo , Humanos , Técnicas Biosensibles/instrumentación , Tacto/fisiología , Dispositivos Electrónicos Vestibles , Piel , Neuronas Aferentes/fisiología , Hidrogeles/química , Percepción del Tacto/fisiología , Percepción del Dolor/fisiologíaRESUMEN
BACKGROUND: Tactile sensitivity and sensory overload in ADHD are well-documented in clinical-, self-, and parent- reports, but empirical evidence is scarce and ambiguous and focuses primarily on children. Here, we compare both empirical and self-report tactile sensitivity and ADHD symptomatology in adults with ADHD and neurotypical controls. We evaluate whether tactile sensitivity and integration is more prevalent in ADHD and whether it is related to ADHD symptom severity. METHODS: Somatosensory evoked potential (SEP) amplitudes were measured in 27 adults with ADHD and 24 controls during four conditions (rest, stroking of the own arm, stroking of the arm by a researcher, and stroking of an object). Participants also filled out questionnaires on tactile sensitivity and ADHD symptoms and performed a Qb-test as an objective measure of ADHD symptom severity. RESULTS: Participants with ADHD self-reported greater tactile sensitivity and ADHD symptom severity than controls and received higher scores on the Qb-test. These values correlated with one another. ADHD participants showed lower tolerable threshold for electrical radial nerve stimulus, and greater reduction in cortical SEP amplitudes during additional tactile stimuli which was correlated with ADHD symptoms. CONCLUSIONS: We find that ADHD symptomatology and touch sensitivity are directly linked, using both self-reports and experimental measures. We also find evidence of tactile sensory overload in ADHD, and an indication that this is linked to inattention specifically. Tactile sensitivity and sensory overload impact the functioning and life quality of many people with ADHD, and clinicians should consider this when treating their patients.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Potenciales Evocados Somatosensoriales , Humanos , Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Masculino , Femenino , Potenciales Evocados Somatosensoriales/fisiología , Adulto , Percepción del Tacto/fisiología , Tacto/fisiología , Autoinforme , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
Sensory feedback provides critical interactive information for the effective use of hand prostheses. Non-invasive neural interfaces allow convenient access to the sensory system, but they communicate a limited amount of sensory information. This study examined a novel approach that leverages a direct and natural sensory afferent pathway, and enables an evoked tactile sensation (ETS) of multiple digits in the projected finger map (PFM) of participants with forearm amputation non-invasively. A bidirectional prosthetic interface was constructed by integrating the non-invasive ETS-based feedback system into a commercial prosthetic hand. The pressure information of five fingers was encoded linearly by the pulse width modulation range of the buzz sensation. We showed that simultaneous perception of multiple digits allowed participants with forearm amputation to identify object length and compliance by using information about contact patterns and force intensity. The ETS enhanced the grasp-and-transport performance of participants with and without prior experience of prosthetic use. The functional test of transport-and-identification further revealed improved execution in classifying object size and compliance using ETS-based feedback. Results demonstrated that the ETS is capable of communicating somatotopically compatible information to participants efficiently, and improves sensory discrimination and closed-loop prosthetic control. This non-invasive sensory interface may establish a viable way to restore sensory ability for prosthetic users who experience the phenomenon of PFM.
Asunto(s)
Miembros Artificiales , Retroalimentación Sensorial , Dedos , Diseño de Prótesis , Tacto , Estimulación Eléctrica Transcutánea del Nervio , Humanos , Masculino , Estimulación Eléctrica Transcutánea del Nervio/métodos , Adulto , Retroalimentación Sensorial/fisiología , Dedos/fisiología , Dedos/inervación , Femenino , Tacto/fisiología , Fuerza de la Mano/fisiología , Antebrazo/inervación , Amputados , Adulto Joven , Percepción del Tacto/fisiología , Desempeño Psicomotor/fisiología , ManoRESUMEN
Rodents use their whisker system to discriminate surface texture. Whisker-based texture discrimination tasks are often used to investigate the mechanisms encoding tactile sensation. One such task is the textured Novel Object Recognition Test (tNORT). It takes advantage of a tendency of rodents to explore novel objects more than familiar ones and assesses the sensitivity of whiskers in discriminating different textures of objects. It requires little training of the animals and the equipment involved is a simple arena with typically two objects placed inside. The success of the test relies on rodents spending sufficient time exploring these objects. Animals may lose interests in such tasks when performed repetitively within a limited time frame. However, such repeated tests may be crucial when establishing a sensitivity threshold of the whisker system. Here we present an adapted rodent tNORT protocol designed to maintain sustained interest in the objects even with repeated testing. We constructed complex objects from three simple-shaped objects. Different textures were provided by sandpapers of varying grit sizes. To minimise olfactory clues, we used the sandy and the laminar side of the same sandpaper as the familiar and novel textures assigned at random. We subsequently conducted repeated tNORTs on eight rats in order to identify a critical threshold of the sandpaper grit size below which rats would be unable to discriminate the sandy from the laminar side. With an inter-test-interval of seven days and after five tNORTs, the protocol enabled us to successfully identify the threshold. We suggest that the proposed tNORT is a useful tool for investigating the sensitivity threshold of the whisker system of rodent, and for testing the effectiveness of an intervention by comparing sensitivity threshold pre- and post-intervention.
Asunto(s)
Reconocimiento en Psicología , Percepción del Tacto , Vibrisas , Animales , Vibrisas/fisiología , Reconocimiento en Psicología/fisiología , Ratas , Percepción del Tacto/fisiología , Masculino , Conducta Exploratoria/fisiología , Discriminación en Psicología/fisiología , Tacto/fisiología , Umbral Sensorial/fisiologíaRESUMEN
Fingernails are specialized features of the primate hand, which are believed to contribute to manual dexterity. The sensorimotor functions of fingernails, however, remain poorly understood. This study investigates the ability of humans to precisely localize touches applied to the fingernail plate. Nine different locations on the fingernail were touched and participants judged the location by clicking a mouse cursor on a photograph of their finger. Performance in this condition was compared with stimuli applied to the skin of the fingertip. The results showed that participants are able to localize touch on the fingernails at substantially higher than chance levels. Moreover, the precision of this ability is not appreciably lower than that of the fingertips. These results show that the fingernail is a highly sensitive sensory organ, which is capable of providing rich spatial information about tactile stimuli.
Asunto(s)
Dedos , Uñas , Tacto , Humanos , Femenino , Masculino , Adulto , Dedos/fisiología , Dedos/anatomía & histología , Percepción del Tacto , Adulto JovenRESUMEN
The intentional binding effect refers to the phenomenon where the perceived temporal interval between a voluntary action and its sensory consequence is subjectively compressed. Prior research revealed the importance of tactile feedback from the keyboard on this effect. Here we examined the necessity of such tactile feedback by utilizing a touch-free key-press device without haptic feedback, and explored how initial/outcome sensory modalities (visual/auditory/tactile) and their consistency influence the intentional binding effect. Participants estimated three delay lengths (250, 550, or 850 ms) between the initial and outcome stimuli. Results showed that regardless of the combinations of sensory modalities between the initial and the outcome stimuli (i.e., modal consistency), the intentional binding effect was only observed in the 250 ms delay condition. This findings indicate a stable intentional binding effect both within and across sensory modalities, supporting the existence of a shared mechanism underlying the binding effect in touch-free voluntary actions.