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1.
Nature ; 579(7798): 256-259, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32132709

RESUMO

Most cortical synapses are local and excitatory. Local recurrent circuits could implement amplification, allowing pattern completion and other computations1-4. Cortical circuits contain subnetworks that consist of neurons with similar receptive fields and increased connectivity relative to the network average5,6. Cortical neurons that encode different types of information are spatially intermingled and distributed over large brain volumes5-7, and this complexity has hindered attempts to probe the function of these subnetworks by perturbing them individually8. Here we use computational modelling, optical recordings and manipulations to probe the function of recurrent coupling in layer 2/3 of the mouse vibrissal somatosensory cortex during active tactile discrimination. A neural circuit model of layer 2/3 revealed that recurrent excitation enhances sensory signals by amplification, but only for subnetworks with increased connectivity. Model networks with high amplification were sensitive to damage: loss of a few members of the subnetwork degraded stimulus encoding. We tested this prediction by mapping neuronal selectivity7 and photoablating9,10 neurons with specific selectivity. Ablation of a small proportion of layer 2/3 neurons (10-20, less than 5% of the total) representing touch markedly reduced responses in the spared touch representation, but not in other representations. Ablations most strongly affected neurons with stimulus responses that were similar to those of the ablated population, which is also consistent with network models. Recurrence among cortical neurons with similar selectivity therefore drives input-specific amplification during behaviour.


Assuntos
Modelos Neurológicos , Neurônios/fisiologia , Córtex Somatossensorial/fisiologia , Animais , Simulação por Computador , Camundongos , Tato/fisiologia
2.
Ann Otol Rhinol Laryngol ; 129(6): 565-571, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31958985

RESUMO

OBJECTIVES: Sensation is an integral component of laryngeal control for breathing, swallowing, and vocalization. Laryngeal sensation is assessed by elicitation of the laryngeal adductor reflex (LAR), a brainstem-mediated adduction of the true vocal folds. During Flexible Endoscopic Evaluations of Swallowing (FEES), the touch method can be used to elicit the LAR to judge laryngeal sensation. Despite the prevalence of this method in clinical practice and research, prior studies have yet to examine inter- and intra-rater reliability. METHODS: Four speech-language pathologists rated 125 randomized video clips for the presence, absence, or inability to rate the LAR. Fifty percent of video clips were re-randomized and re-rated 1 week later. Raters then created guidelines and participated in formal consensus training sessions on a separate set of videos. Ratings were repeated post-training. RESULTS: Overall inter-rater reliability was fair (κ = 0.22) prior to training. Pre-training intra-rater reliability ranged from fair (κ = 0.35) to almost perfect (κ = 0.89). Inter-rater reliability significantly improved after training (κ = 0.42, P < .001), though agreement did not reach prespecified acceptable levels (κ ≥ 0.80). Post-training intra-rater reliability ranged from moderate (κ = 0.49) to almost perfect (κ = 0.85). CONCLUSION: Adequate inter-rater reliability was not achieved when rating isolated attempts to elicit the LAR. Acceptable within-rater reliability was observed in some raters 1 week after initial ratings, suggesting that ratings may remain consistent within raters over a short period of time. Limitations and considerations for future research using the touch method are discussed.


Assuntos
Transtornos de Deglutição/diagnóstico , Laringoscopia , Reflexo Anormal/fisiologia , Patologia da Fala e Linguagem , Tato/fisiologia , Prega Vocal/fisiopatologia , Adulto , Idoso , Transtornos de Deglutição/fisiopatologia , Pessoal de Saúde , Humanos , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Prospectivos , Reprodutibilidade dos Testes
3.
Neuron ; 105(1): 16-33, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31917952

RESUMO

Many brain areas modulate their activity during vibrotactile tasks. The activity from these areas may code the stimulus parameters, stimulus perception, or perceptual reports. Here, we discuss findings obtained in behaving monkeys aimed to understand these processes. In brief, neurons from the somatosensory thalamus and primary somatosensory cortex (S1) only code the stimulus parameters during the stimulation periods. In contrast, areas downstream of S1 code the stimulus parameters during not only the task components but also perception. Surprisingly, the midbrain dopamine system is an actor not considered before in perception. We discuss the evidence that it codes the subjective magnitude of a sensory percept. The findings reviewed here may help us to understand where and how sensation transforms into perception in the brain.


Assuntos
Neurônios Dopaminérgicos/fisiologia , Mesencéfalo/fisiologia , Córtex Somatossensorial/fisiologia , Tálamo/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Animais
4.
Ann Neurol ; 87(2): 194-205, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31875975

RESUMO

OBJECTIVE: Sensory dysfunction is a common consequence of many forms of neurological injury, including stroke and nerve damage. Rehabilitative paradigms that incorporate sensory retraining can provide modest benefits, but the majority of patients are left with lasting sensory loss. We have developed a novel strategy that uses closed-loop vagus nerve stimulation (VNS) paired with tactile rehabilitation to enhance synaptic plasticity and facilitate recovery of sensory function. METHODS: A clinical case report provides initial evidence that a similar implementation of closed-loop VNS paired with a tactile rehabilitation regimen could improve recovery of somatosensory function. Here, we sought to build on these promising initial clinical data and rigorously evaluate the ability of VNS paired with tactile rehabilitation to improve recovery in an animal model of chronic sensory loss. The study design, including planned sample size, assessments, and statistical comparisons, was preregistered prior to beginning data collection (https://osf.io/xsnj5/). RESULTS: VNS paired with tactile rehabilitation resulted in a significant and nearly complete recovery of mechanosensory withdrawal thresholds. Equivalent tactile rehabilitation without VNS failed to improve sensory function. This VNS-dependent restoration of sensory thresholds was maintained for several months after the cessation of stimulation, illustrating long-term benefits. Moreover, VNS paired with tactile rehabilitation resulted in significant generalized improvements in other measures of sensorimotor forepaw function. INTERPRETATION: Given the safety and tolerability of VNS therapy, these findings suggest that incorporating VNS paired with sensory retraining into rehabilitative regimens may represent a fundamentally new method to increase recovery of sensory function after neurological injury. ANN NEUROL 2020;87:194-205.


Assuntos
Terapia Combinada/métodos , Transtornos das Sensações/reabilitação , Transtornos das Sensações/terapia , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/terapia , Tato/fisiologia , Estimulação do Nervo Vago , Animais , Feminino , Ratos , Recuperação de Função Fisiológica/fisiologia , Transtornos das Sensações/complicações , Limiar Sensorial/fisiologia , Acidente Vascular Cerebral/complicações
5.
Acta Psychol (Amst) ; 202: 102960, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31862578

RESUMO

Quantities can be represented by different formats (e.g. symbolic or non-symbolic) and conveyed via different modalities (e.g. tactile or visual). Despite different priming curves: V-shape and step-shape for place and summation coded representation, respectively, the occurrence of priming effect supports the notion of different format overlap on the same mental number line. However, little is known about tactile-visual overlap of symbolic numerosities i.e. Braille numbers to Arabic digits on the magnitude number representation. Here, in a priming experiment, we tested a unique group of sighted Braille readers to investigate whether tactile Braille digits would activate a place-coding type of mental number representation (V-shape), analogous to other symbolic formats. The primes were either tactile Braille digits presented on a Braille display or number words presented on a computer screen. The targets were visually presented Arabic digits, and subjects performed a naming task. Our results reveal a V-shape priming function for both prime formats: tactile Braille and written words representing numbers, with strongest priming for primes of identical value (e.g. "four" and "4"), and a symmetrical decrease of priming strength for neighboring numbers, which indicates that the observed priming is due to identity priming. We thus argue that the magnitude information is processed according to a shared phonological code, independent of the input modality.


Assuntos
Cegueira/psicologia , Auxiliares de Comunicação para Pessoas com Deficiência/psicologia , Idioma , Estimulação Luminosa/métodos , Leitura , Tato/fisiologia , Adulto , Mundo Árabe , Feminino , Humanos , Masculino , Adulto Jovem
6.
Proc Natl Acad Sci U S A ; 117(2): 1191-1200, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31879342

RESUMO

Intracortical microstimulation (ICMS) of the somatosensory cortex evokes vivid tactile sensations and can be used to convey sensory feedback from brain-controlled bionic hands. Changes in ICMS frequency lead to changes in the resulting sensation, but the discriminability of frequency has only been investigated over a narrow range of low frequencies. Furthermore, the sensory correlates of changes in ICMS frequency remain poorly understood. Specifically, it remains to be elucidated whether changes in frequency only modulate sensation magnitude-as do changes in amplitude-or whether they also modulate the quality of the sensation. To fill these gaps, we trained monkeys to discriminate the frequency of ICMS pulse trains over a wide range of frequencies (from 10 to 400 Hz). ICMS amplitude also varied across stimuli to dissociate sensation magnitude from ICMS frequency and ensure that animals could not make frequency judgments based on magnitude. We found that animals could consistently discriminate ICMS frequency up to ∼200 Hz but that the sensory correlates of frequency were highly electrode dependent: On some electrodes, changes in frequency were perceptually distinguishable from changes in amplitude-seemingly giving rise to a change in sensory quality; on others, they were not. We discuss the implications of our findings for neural coding and for brain-controlled bionic hands.


Assuntos
Estimulação Elétrica/métodos , Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Animais , Escala de Avaliação Comportamental , Eletrodos Implantados , Retroalimentação Sensorial , Macaca mulatta , Masculino
7.
Sensors (Basel) ; 20(1)2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31878001

RESUMO

Grasping and manipulation with anthropomorphic robotic and prosthetic hands presents a scientific challenge regarding mechanical design, sensor system, and control. Apart from the mechanical design of such hands, embedding sensors needed for closed-loop control of grasping tasks remains a hard problem due to limited space and required high level of integration of different components. In this paper we present a scalable design model of artificial fingers, which combines mechanical design and embedded electronics with a sophisticated multi-modal sensor system consisting of sensors for sensing normal and shear force, distance, acceleration, temperature, and joint angles. The design is fully parametric, allowing automated scaling of the fingers to arbitrary dimensions in the human hand spectrum. To this end, the electronic parts are composed of interchangeable modules that facilitate the mechanical scaling of the fingers and are fully enclosed by the mechanical parts of the finger. The resulting design model allows deriving freely scalable and multimodally sensorised fingers for robotic and prosthetic hands. Four physical demonstrators are assembled and tested to evaluate the approach.


Assuntos
Robótica , Tato/fisiologia , Desenho de Equipamento , Dedos , Força da Mão , Humanos
8.
PLoS One ; 14(12): e0224174, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841510

RESUMO

Body ownership relies on spatiotemporal correlations between multisensory signals and visual cues specifying oneself such as body form and orientation. The mechanism for the integration of bodily signals remains unclear. One approach to model multisensory integration that has been influential in the multisensory literature is Bayesian causal inference. This specifies that the brain integrates spatial and temporal signals coming from different modalities when it infers a common cause for inputs. As an example, the rubber hand illusion shows that visual form and orientation cues can promote the inference of a common cause (one's body) leading to spatial integration shown by a proprioceptive drift of the perceived location of the real hand towards the rubber hand. Recent studies investigating the effect of visual cues on temporal integration, however, have led to conflicting findings. These could be due to task differences, variation in ecological validity of stimuli and/or small samples. In this pre-registered study, we investigated the influence of visual information on temporal integration using a visuo-tactile temporal order judgement task with realistic stimuli and a sufficiently large sample determined by Bayesian analysis. Participants viewed videos of a touch being applied to plausible or implausible visual stimuli for one's hand (hand oriented plausibly, hand rotated 180 degrees, or a sponge) while also being touched at varying stimulus onset asynchronies. Participants judged which stimulus came first: viewed or felt touch. Results show that visual cues do not modulate visuo-tactile temporal order judgements. This is not in line with the idea that bodily signals indicating oneself influence the integration of multisensory signals in the temporal domain. The current study emphasises the importance of rigour in our methodologies and analyses to advance the understanding of how properties of multisensory events affect the encoding of temporal information in the brain.


Assuntos
Orientação Espacial/fisiologia , Percepção do Tato/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Teorema de Bayes , Imagem Corporal , Sinais (Psicologia) , Feminino , Mãos , Humanos , Masculino , Pessoa de Meia-Idade , Orientação , Propriocepção/fisiologia , Tato/fisiologia
9.
Acta Psychol (Amst) ; 201: 102950, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31698171

RESUMO

Considering object identification and recognition as well as human interaction with objects, texture as a surface property plays a crucial role. A deeper understanding of tactile aesthetics can be useful in the applied field such as in product designs that appeal more to our senses and that are more effective in eliciting certain emotional responses from a potential consumer. In the present study, behavioral experiments were performed using unfamiliar custom-made dot pattern stimuli under two complementary questionings. The first question focused on the tactile perceptive attributes related to topographical characteristics of the textures exhibited by the material surfaces. The second question focused on the texture pleasantness related both to the perceptive attributes and to the topographical characteristics of the textures. The perspective of this work opens on complementary fields of research such as neurosciences to determine the brain mechanisms in the processing of the pleasantness of tactile stimuli.


Assuntos
Estética/psicologia , Ódio , Percepção do Tato/fisiologia , Tato/fisiologia , Vibração , Adulto , Emoções/fisiologia , Feminino , Humanos , Masculino , /fisiologia
10.
Artigo em Inglês | MEDLINE | ID: mdl-31614840

RESUMO

Physical manifestations of Turner syndrome include short stature, a webbed neck, and a shield chest with widely spaced nipples. An aspect of the disease which has not been sufficiently explored so far is the tactile sensitivity of Turner syndrome patients. Thus, the aim of the study was to assess the threshold of tactile sensitivity on hands and feet of women suffering from Turner syndrome. Information on the participants of the study was collected on the basis of questionnaires, as well as anthropometric measurements using a skinfold caliper. Semmes-Weinstein Aesthesiometer was used to find the tactile sensitivity threshold of hands and feet of study participants. Based on the results of the study, significant differences in tactile sensitivity between women with Turner syndrome and healthy women were found. Affected women seem be more sensitive to the touch on the feet than healthy volunteers. The results of the study showed that the tactile sensitivity of women with Turner syndrome is different from that of healthy women.


Assuntos
Percepção do Tato/fisiologia , Tato/fisiologia , Síndrome de Turner/complicações , Síndrome de Turner/fisiopatologia , Adolescente , Adulto , Criança , Feminino , Humanos , Pessoa de Meia-Idade , Adulto Jovem
11.
Nat Commun ; 10(1): 4634, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604919

RESUMO

Touch is a fundamental aspect of social, parental and sexual behavior. In contrast to our detailed knowledge about cortical processing of non-social touch, we still know little about how social touch impacts cortical circuits. We investigated neural activity across five frontal, motor and sensory cortical areas in rats engaging in naturalistic social facial touch. Information about social touch and the sex of the interaction partner (a biologically significant feature) is a major determinant of cortical activity. 25.3% of units were modulated during social touch and 8.3% of units displayed 'sex-touch' responses (responded differently, depending on the sex of the interaction partner). Single-unit responses were part of a structured, partner-sex- and, in some cases, subject-sex-dependent population response. Spiking neural network simulations indicate that a change in inhibitory drive might underlie these population dynamics. Our observations suggest that socio-sexual characteristics of touch (subject and partner sex) widely modulate cortical activity and need to be investigated with cellular resolution.


Assuntos
Comportamento Social , Córtex Somatossensorial/fisiologia , Tato/fisiologia , Vibrissas/fisiologia , Animais , Comportamento Animal , Feminino , Masculino , Rede Nervosa , Dinâmica Populacional , Ratos , Análise de Regressão , Fatores Sexuais
13.
Am J Occup Ther ; 73(5): 7305205010p1-7305205010p14, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31484025

RESUMO

IMPORTANCE: Sensory symptoms in people with autism spectrum disorder (ASD) are commonly reported by researchers. However, an often overlooked sensory aspect of ASD is sensory discrimination in general, and somatosensory discrimination in particular. OBJECTIVE: To examine what has and what has not yet been learned concerning the somatosensory discrimination abilities of people with ASD and to reveal gaps warranting further research. DESIGN: Scoping review of clinical studies published 1995-2017 located through searches of PsycNET, PubMed, ERIC, and Google Scholar. Inclusion criteria were English-language peer-reviewed studies with (1) participants diagnosed with ASD, (2) a specific somatosensory discrimination measure, and (3) a comparison group. No age or intellectual exclusion criteria were established; studies were excluded if they were theoretical or descriptive, did not incorporate a control group, focused only on neurology or genetics, or used simple threshold detection measures or somatosensory measures integrated with other measures. The final search yielded 12 comparative articles discussing tactile and proprioceptive discrimination in people with ASD. RESULTS: Overall, most results showed atypical somatosensory discrimination in people with ASD, especially among young children. The relationship between sensory discrimination abilities and other sensory symptoms and ASD symptoms is briefly discussed. CONCLUSIONS AND RELEVANCE: Heterogeneous findings concerning somatosensory discrimination in people with ASD shed light on underlying mechanisms of these disorders and can contribute to improvement of occupational therapy intervention for this population. WHAT THIS ARTICLE ADDS: The occupational therapy evaluation of people with ASD can benefit from addressing somatosensory discrimination and its contribution to other clinical symptoms. This type of assessment can help improve intervention strategies for people with ASD by promoting a focus on the effect of discrimination deficits on daily function.


Assuntos
Transtorno do Espectro Autista , Transtorno do Espectro Autista/terapia , Criança , Pré-Escolar , Humanos , Tato/fisiologia
14.
Dev Cogn Neurosci ; 39: 100703, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31487608

RESUMO

Preterm birth is a significant risk factor for a range of long-term health problems and developmental disabilities. Though touch plays a central role in many perinatal care strategies, the neurobiological basis of these approaches is seldom considered. C-Tactile afferents (CTs) are a class of unmyelinated nerve fibre activated by low force, dynamic touch. Consistent with an interoceptive function, touch specifically targeted to activate CTs activates posterior insular cortex and has been reported to reduce autonomic arousal. The present study compared the effect of 5 min of CT optimal velocity stroking touch to 5 min of static touch on the heart-rate and oxygen saturation levels of preterm infants between 28- & 37-weeks gestational age. CT touch produced a significant decrease in infants' heart-rates and increase in their blood oxygenation levels, which sustained throughout a 5-min post-touch period. In contrast, there was no significant change in heart-rate or blood oxygenation levels of infants receiving static touch. These findings provide support for the hypothesis that CTs signal the affective quality of nurturing touch, providing a neurobiological substrate for the apparent beneficial effects of neonatal tactile interventions and offering insight for their optimisation.


Assuntos
Nível de Alerta/fisiologia , Recém-Nascido Prematuro/fisiologia , Fibras Nervosas Amielínicas/fisiologia , Neurônios Aferentes/fisiologia , Percepção do Tato/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro/psicologia , Masculino , Distribuição Aleatória , Tato/fisiologia
15.
Nat Commun ; 10(1): 4019, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488820

RESUMO

Biological cellular structures have inspired many scientific disciplines to design synthetic structures that can mimic their functions. Here, we closely emulate biological cellular structures in a rationally designed synthetic multicellular hybrid ion pump, composed of hydrogen-bonded [EMIM+][TFSI-] ion pairs on the surface of silica microstructures (artificial mechanoreceptor cells) embedded into thermoplastic polyurethane elastomeric matrix (artificial extracellular matrix), to fabricate ionic mechanoreceptor skins. Ionic mechanoreceptors engage in hydrogen bond-triggered reversible pumping of ions under external stimulus. Our ionic mechanoreceptor skin is ultrasensitive (48.1-5.77 kPa-1) over a wide spectrum of pressures (0-135 kPa) at an ultra-low voltage (1 mV) and demonstrates the ability to surpass pressure-sensing capabilities of various natural skin mechanoreceptors (i.e., Merkel cells, Meissner's corpuscles, Pacinian corpuscles). We demonstrate a wearable drone microcontroller by integrating our ionic skin sensor array and flexible printed circuit board, which can control directions and speed simultaneously and selectively in aerial drone flight.


Assuntos
Técnicas Biossensoriais/instrumentação , Eletroquímica/instrumentação , Ligação de Hidrogênio , Mecanorreceptores/fisiologia , Mecanotransdução Celular/fisiologia , Fenômenos Fisiológicos da Pele , Adulto , Biomimética/instrumentação , Técnicas Biossensoriais/métodos , Humanos , Mecanorreceptores/química , Mecanorreceptores/citologia , Células de Merkel/metabolismo , Estimulação Física , Poliuretanos , Pressão , Sílica Gel , Pele/citologia , Tato/fisiologia
16.
Biomed Res Int ; 2019: 9073073, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31380442

RESUMO

The study investigated touch and pain sensations and the correlation between them in diadynamic current (DD) and transcutaneous electrical nerve stimulation (TENS), electrotherapies commonly applied in musculoskeletal disorders and occupational rehabilitation medicine. Forty healthy subjects were treated with either DD (n=20) or TENS (n=20). Each treatment consisted of three sessions with one-week interval. Touch sensation was determined with the JVP Domes esthesiometer, pain sensation with pressure pain threshold (PPT), and pressure pain tolerance threshold (PPTO) by an algometer. During each session the measurements were performed before the application of the procedure (T0), immediately after it (T1), and 30 minutes after the end of the procedure (T2). Both DD and TENS increased touch sensation (p<0.01) and did not significantly alter PPT and PPTO (p>0.05). No statistically significant differences in short-term effects, i.e., 3 weeks of the trial, were noted between DD and TENS in their influence on touch and pain sensations (p>0.05). There was a high significant correlation between touch and pain sensations in DD (r=0.86). TENS and DD caused similar analgesic effects. DD, which is shorter in the duration of the treatment, may comprise a realistic alternative to TENS in clinical practice of pain management.


Assuntos
Terapia por Estimulação Elétrica , Manejo da Dor/métodos , Tato/fisiologia , Estimulação Elétrica Nervosa Transcutânea/métodos , Adulto , Feminino , Humanos , Masculino , Medição da Dor/métodos , Percepção da Dor/fisiologia , Adulto Jovem
17.
Artigo em Inglês | MEDLINE | ID: mdl-31413893

RESUMO

Background: Sensory tricks are compensatory gestures that cervical dystonia (CD) patients use to reduce abnormal neck posture and movements. Although sensory tricks are common in CD, little is known about whether trick efficacy changes over time or has effect on quality of life. Methods: We analyzed clinical data and video recordings from 188 patients with isolated CD. We calculated the duration of CD and assessed the Toronto Western Spasmodic Torticollis Rating Scales and the Cervical Dystonia Impact Profile (CDIP-58). Results: A longer duration of CD corresponded to a less effective sensory trick (r(187) = 0.1901, p = 0.009). Patients who demonstrated more effective sensory tricks reported higher sleep-related quality of life than patients with less effective sensory tricks (r(187) = 0.1680, p = 0.0212). There were no significant relationships between the effectiveness of a sensory trick and the other aspects of quality of life as measured by the CDIP-58. Discussion: Patients who have had CD longer had less effective sensory tricks consistent with patients' verbal reports of previously having a trick that no longer works. Patients should be apprised of a wide variety of sensory tricks because their previous tricks may lose efficacy over time and because more effective tricks are associated with higher sleep-related quality of life.


Assuntos
Distúrbios Distônicos/fisiopatologia , Qualidade de Vida , Sono/fisiologia , Torcicolo/fisiopatologia , Adulto , Idoso , Distúrbios Distônicos/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Torcicolo/complicações , Tato/fisiologia
18.
Acta Psychol (Amst) ; 199: 102900, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31400650

RESUMO

There are many similarities and differences between the human hands and feet. On a psychological level, there is some evidence from clinical disorders and studies of tactile localisation in healthy adults for deep functional connections between the hands and feet. One form these connections may take is in common high-level mental representations of the hands and feet. Previous studies have shown that there are systematic, but distinct patterns of confusion found between both the fingers and toes. Further, there are clear individual differences between people in the exact patterns of mislocalisations. Here, we investigated whether these idiosyncratic differences in tactile localisation are shared between the fingers and toes, which may indicate a shared high-level representation. We obtained confusion matrices showing the pattern of mislocalisation on the hairy skin surfaces of both the fingers and toes. Using a decoding approach, we show that idiosyncratic differences in individuals' pattern of confusions are shared across the fingers and toes, despite different overall patterns of confusions. These results suggest that there is a common representation of the fingers and toes.


Assuntos
Dedos/fisiologia , Lateralidade Funcional/fisiologia , Dedos do Pé/fisiologia , Tato/fisiologia , Adulto , Feminino , Humanos , Masculino , Estimulação Física/métodos
19.
IEEE Int Conf Rehabil Robot ; 2019: 760-765, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31374722

RESUMO

Motivation plays a crucial role in motor learning and neurorehabilitation. Participants' motivation could decline to a point where they may stop training when facing a very difficult task. Conversely, participants may perform well and consider the training boring if the task is too easy. In this paper, we present a combination of a virtual reality environment with different robotic training strategies that modify task functional difficulty to enhance participants' motivation. We employed a pneumatically driven robotic stepper as a haptic interface. We first evaluated the use of disturbance observers as acceleration controllers to provide high robustness to varying system parameters, unmodeled dynamics and unknown disturbances associated with pneumatic control. The locomotor task to be learned in the virtual reality environment consisted of steering a recumbent bike to follow a desired path by changing the movement frequency of the dominant leg. The motor task was specially designed to engage implicit learning -i.e., learning without conscious recognition of what is learned. A haptic assistance strategy was developed in order to reduce the task functional difficulty during practice. In a feasibility study with eight healthy participants, we found that the haptic assistance provided by the robotic device successfully contributed to improve task performance during training, especially for less skilled participants. Furthermore, we found a negative correlation between participants' motivation and performance error when training with haptic assistance, suggesting that haptic assistance has a great potential to enhance motivation during motor training.


Assuntos
Aprendizagem , Motivação , Robótica , Tato/fisiologia , Realidade Virtual , Adulto , Algoritmos , Fenômenos Biomecânicos , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino
20.
IEEE Int Conf Rehabil Robot ; 2019: 175-180, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31374626

RESUMO

Haptic-enabled teleoperated robots can help children with physical disabilities to reach toys by applying haptic guidance towards their toys, thus compensating for their limitations in reaching and manipulating objects. In this article we preliminarily tested a learning from demonstration (LfD) approach, where a robotic system learnt the surface that best approximated to all motion trajectories demonstrated by the participants while playing a whack-a-mole game. The end-goal of the system is for therapists or parents to demonstrate to it how to play a game, and then be used by children with physical disabilities. In this study, four adults without disabilities participated, to identify aspects that will be necessary to improve before conducting trials with children. During the demonstration phase, participants played the game in normal teleoperation, assuming the role of the therapist/parent. Then, the surface was modeled using a neural network. Participants played the game without and with the haptic guidance. The movements of the robotic system were mirrored to induce errors in movements, and thus require the guidance. Participants spent more time, moved the robot longer distances, and had jerkier movements when they played the game with the guidance than without it. Possible reasons were discussed, and several solutions were proposed to improve the system. The main contribution of this paper was the learning of a surface instead of learning a single motion trajectory.


Assuntos
Aprendizagem , Movimento (Física) , Tato/fisiologia , Adulto , Humanos , Robótica , Adulto Jovem
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