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1.
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
2.
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
3.
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
4.
Nat Commun ; 10(1): 4405, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31562319

RESUMO

The emergence of smart electronics, human friendly robotics and supplemented or virtual reality demands electronic skins with both tactile and touchless perceptions for the manipulation of real and virtual objects. Here, we realize bifunctional electronic skins equipped with a compliant magnetic microelectromechanical system able to transduce both tactile-via mechanical pressure-and touchless-via magnetic fields-stimulations simultaneously. The magnetic microelectromechanical system separates electric signals from tactile and touchless interactions into two different regions, allowing the electronic skins to unambiguously distinguish the two modes in real time. Besides, its inherent magnetic specificity overcomes the interference from non-relevant objects and enables signal-programmable interactions. Ultimately, the magnetic microelectromechanical system enables complex interplay with physical objects enhanced with virtual content data in augmented reality, robotics, and medical applications.


Assuntos
Fenômenos Fisiológicos da Pele , Percepção do Tato/fisiologia , Tato , Dispositivos Eletrônicos Vestíveis , Algoritmos , Eletricidade , Fenômenos Eletromagnéticos , Eletrônica/instrumentação , Eletrônica/métodos , Humanos , Magnetismo , Robótica , Transdutores
5.
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
6.
PLoS One ; 14(8): e0219737, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31398207

RESUMO

Numerous factors affect reaction times to vibrotactile cues. Therefore, it is important to consider the relative magnitudes of these time delays when designing vibrotactile displays for real-time applications. The objectives of this study were to quantify reaction times to typical vibrotactile stimuli parameters through direct comparison within a single experimental setting, and to determine the relative importance of these factors on reaction times. Young (n = 10, 21.9 ± 1.3 yrs) and older adults (n = 13, 69.4 ± 5.0 yrs) performed simple reaction time tasks by responding to vibrotactile stimuli using a thumb trigger while frequency, location, auditory cues, number of tactors in the same location, and tactor type were varied. Participants also performed a secondary task in a subset of the trials. The factors investigated in this study affected reaction times by 20-300 ms (reaction time findings are noted in parentheses) depending on the specific stimuli condition. In general, auditory cues generated by the tactors (<20 ms), vibration frequency (<20 ms), number of tactors in the same location (<30 ms) and tactor type (<50 ms) had relatively small effects on reaction times, while stimulus location (20-120 ms) and secondary cognitive task (>130 ms) had relatively large effects. Factors affected young and older adults' reaction times in a similar manner, but with different magnitudes. These findings can inform the development of vibrotactile displays by enabling designers to directly compare the relative effects of key factors on reaction times.


Assuntos
Envelhecimento/fisiologia , Tempo de Reação/fisiologia , Vibração , Idoso , Sinais (Psicologia) , Feminino , Humanos , Masculino , Estimulação Física , Percepção do Tato/fisiologia , Adulto Jovem
7.
PLoS Biol ; 17(8): e3000431, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31454360

RESUMO

Motion is an essential component of everyday tactile experience: most manual interactions involve relative movement between the skin and objects. Much of the research on the neural basis of tactile motion perception has focused on how direction is encoded, but less is known about how speed is. Perceived speed has been shown to be dependent on surface texture, but previous studies used only coarse textures, which span a restricted range of tangible spatial scales and provide a limited window into tactile coding. To fill this gap, we measured the ability of human observers to report the speed of natural textures-which span the range of tactile experience and engage all the known mechanisms of texture coding-scanned across the skin. In parallel experiments, we recorded the responses of single units in the nerve and in the somatosensory cortex of primates to the same textures scanned at different speeds. We found that the perception of speed is heavily influenced by texture: some textures are systematically perceived as moving faster than are others, and some textures provide a more informative signal about speed than do others. Similarly, the responses of neurons in the nerve and in cortex are strongly dependent on texture. In the nerve, although all fibers exhibit speed-dependent responses, the responses of Pacinian corpuscle-associated (PC) fibers are most strongly modulated by speed and can best account for human judgments. In cortex, approximately half of the neurons exhibit speed-dependent responses, and this subpopulation receives strong input from PC fibers. However, speed judgments seem to reflect an integration of speed-dependent and speed-independent responses such that the latter help to partially compensate for the strong texture dependence of the former.


Assuntos
Percepção de Movimento/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Adulto , Animais , Feminino , Humanos , Macaca mulatta , Masculino , Movimento , Neurônios/fisiologia , Pele , Córtex Somatossensorial/fisiologia , Adulto Jovem
8.
J Vis ; 19(9): 9, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426084

RESUMO

Tactile suppression refers to the phenomenon that tactile signals are attenuated during movement planning and execution when presented on a moving limb compared to rest. It is usually explained in the context of the forward model of movement control that predicts the sensory consequences of an action. Recent research suggests that aging increases reliance on sensorimotor predictions resulting in stronger somatosensory suppression. However, the mechanisms contributing to this age effect remain to be clarified. We measured age-related differences in tactile suppression during reaching and investigated the modulation by cognitive processes. A total of 23 younger (18-27 years) and 26 older (59-78 years) adults participated in our study. We found robust suppression of tactile signals when executing reaching movements. Age group differences corroborated stronger suppression in old age. Cognitive task demands during reaching, although overall boosting suppression effects, did not modulate the age effect. Across age groups, stronger suppression was associated with lower individual executive capacities. There was no evidence that baseline sensitivity had a prominent impact on the magnitude of suppression. We conclude that aging alters the weighting of sensory signals and sensorimotor predictions during movement control. Our findings suggest that individual differences in tactile suppression are critically driven by executive functions.


Assuntos
Envelhecimento/fisiologia , Movimento/fisiologia , Percepção do Tato/fisiologia , Adolescente , Adulto , Idoso , Braço , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
9.
Exp Brain Res ; 237(9): 2297-2304, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273391

RESUMO

Incomplete recovery of sensory function is common after peripheral nerve injury (PNI). Despite reinnervation following injury, disorganized cortical representations persist and may contribute to functional deficits. There is a dearth of literature characterizing cortical responses after PNI in rodent models. Here we develop a quantitative electrophysiological method for mapping forepaw digit responses in primary somatosensory cortex (S1) of rats. We tested the hypothesis that PNI in the forelimb would generate significant, long lasting sensory deficits, and corresponding disorganization in S1. Rats underwent a transection of the proximal segment of the median and ulnar nerves in the forelimb followed by tubular repair. 4-12 months after nerve injury, we tested mechanosensory withdrawal thresholds and mapped S1 responses to mechanical stimulation of the digits. PNI produces persistent elevation of mechanical withdrawal thresholds, consistent with an impairment in sensory function. Assessment of cortical neurophysiology reveals a substantial disorganization of S1 somatotopy. Additionally, we document degraded timing and digit specificity of cortical responses. This quantitative measurement of long-term changes in S1 digit representations after forelimb nerve injury in rodents provides a framework for further studies focused on the development of therapeutic strategies to restore cortical and sensory function.


Assuntos
Membro Anterior/fisiopatologia , Nervo Mediano/fisiopatologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Limiar Sensorial/fisiologia , Córtex Somatossensorial/fisiopatologia , Dedos do Pé/fisiopatologia , Percepção do Tato/fisiologia , Nervo Ulnar/fisiopatologia , Animais , Modelos Animais de Doenças , Eletroencefalografia , Feminino , Nervo Mediano/lesões , Estimulação Física , Ratos , Ratos Sprague-Dawley , Nervo Ulnar/lesões
10.
Exp Brain Res ; 237(9): 2387-2395, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31292694

RESUMO

The large systematic deviations in haptic parallelity matching are most likely due to the biasing influence of the hand-centered egocentric reference frame. Previous results showed that eliminating or reducing this bias resulted in smaller deviations, with significantly larger effects observed in female participants. The current study investigated the effect of reducing the egocentric bias in a pure haptic condition. Blind-folded male and female participants had to feel the orientation of a reference bar with their non-dominant hand and to parallel this orientation on a test bar with their dominant hand. In one condition, they were instructed to use their flat-stretched hand to feel and match the bars, while in the other condition (HPF), they were instructed to set the test bar while gripping the bar with the fingers and thumb. It was hypothesized that the latter would reduce the biasing influence of the hand-centered egocentric reference frame. Results showed that this was indeed the case. Deviations were significantly smaller for HPF; however, this effect was the same in both genders. The previously observed gender effect, showing a significantly larger improvement for women when reducing the influence of the egocentric reference frame, was not replicated.


Assuntos
Mãos/fisiologia , Atividade Motora/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Percepção do Tato/fisiologia , Adulto , Feminino , Humanos , Masculino , Fatores Sexuais , Adulto Jovem
11.
Hum Mov Sci ; 67: 102495, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31326741

RESUMO

BACKGROUND: Adding haptic input by lightly touching a railing or using haptic anchors may improve walking balance control. Typical use of the railing(s) and haptic anchors requires the use of one and two arms in an extended position, respectively. It is unclear whether it is arm configuration and/or the number of arms used or the addition of sensory input that affects walking balance control. RESEARCH QUESTION: This study examined whether using one arm or two arms to add haptic input through light touch on a railing or using the haptic anchors affects walking balance control. METHODS: In this study, young adults (n = 24) walked while using (actual use) or pretending to use (pretend use) the railing(s) and haptic anchors with one or two arms. Inertial-based sensors (Mobility Lab, APDM) were used to measure stride velocity, relative time spent in double support (%DS), and peak normalized medio-lateral trunk velocity (pnMLTV). RESULTS: Using two arms lead to a decrease in pnMLTV compared to using one arm and pnMLTV was lower in the actual use trials compared to the pretend use trials for the anchors only. Stride velocity and %DS did not change between trials when one or two arms were used or when participants actually or pretended to use the haptic tools. Participants walked slower when using the railing compared to the anchors. SIGNIFICANCE: The importance of considering the number of arms is highlighted in the improved balance control when using two arms with either tool. The augmented sensory input adds to the stabilizing effect of arm configuration for the anchors but not the railings. These results have implications for future research and rehabilitation efforts emphasizing sensorimotor integration to improve walking balance control.


Assuntos
Braço/fisiologia , Equilíbrio Postural/fisiologia , Caminhada/fisiologia , Adulto , Retroalimentação Sensorial/fisiologia , Feminino , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Amplitude de Movimento Articular , Percepção do Tato/fisiologia , Adulto Jovem
12.
J Exp Psychol Hum Percept Perform ; 45(10): 1375-1388, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31343245

RESUMO

To respond to multisensory information, inputs from different sensory modalities must be processed and combined. Recently, overt spatial attention was shown to be a crucial factor modulating the processing of irrelevant audiovisual multisensory stimuli. Here, we investigate the processing of task-irrelevant visuotactile features in a multisensory flanker interference task incorporating visuotactile target and distractor stimuli. The congruency between the target and distractor features was varied orthogonally. Across three experiments, overt spatial attention and the spatial separation between the distractor and the target were varied systematically. When fixating the distractor, the processing of the visual and tactile distractor features was not independent. Manipulating overt spatial attention as well as the spatial separation between the target and distractor impacted multisensory distractor processing. These results are consistent with those approaches emphasizing the role of attention in multisensory processing specifically in relation to the cognitive load or selection difficulty of the task situation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Atenção/fisiologia , Atividade Motora/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Percepção do Tato/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
14.
Nat Neurosci ; 22(9): 1438-1449, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31332375

RESUMO

How the somatosensory cortex (S1) encodes complex patterns of touch, such as those that occur during tactile exploration, is poorly understood. In the mouse whisker S1, temporally dense stimulation of local whisker pairs revealed that most neurons are not classical single-whisker feature detectors, but instead are strongly tuned to two-whisker sequences that involve the columnar whisker (CW) and one specific surround whisker (SW), usually in a SW-leading-CW order. Tuning was spatiotemporally precise and diverse across cells, generating a rate code for local motion vectors defined by SW-CW combinations. Spatially asymmetric, sublinear suppression for suboptimal combinations and near-linearity for preferred combinations sharpened combination tuning relative to linearly predicted tuning. This resembles computation of motion direction selectivity in vision. SW-tuned neurons, misplaced in the classical whisker map, had the strongest combination tuning. Thus, each S1 column contains a rate code for local motion sequences involving the CW, thus providing a basis for higher-order feature extraction.


Assuntos
Mecanorreceptores/citologia , Córtex Somatossensorial/citologia , Percepção do Tato/fisiologia , Vibrissas/inervação , Animais , Camundongos , Tato/fisiologia
15.
Exp Brain Res ; 237(9): 2167-2184, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31209510

RESUMO

Previous work has highlighted the role of haptic feedback for manual dexterity, in particular for the control of precision grip forces between the index finger and thumb. It is unclear how fine motor skills involving more than just two digits might be affected, especially given that loss of sensation from the hand affects many neurological patients, and impacts on everyday actions. To assess the functional consequences of haptic deficits on multi-digit grasp of objects, we studied the ability of three rare individuals with permanent large-fibre sensory loss involving the entire upper limb. All three reported difficulties in everyday manual actions (ABILHAND questionnaire). Their performance in a reach-grasp-lift task was compared to that of healthy controls. Twenty objects of varying shape, mass, opacity and compliance were used. In the reach-to-grasp phase, we found slower movement, larger grip aperture and less dynamic modulation of grip aperture in deafferented participants compared to controls. Hand posture during the lift phase also differed; deafferented participants often adopted hand postures that may have facilitated visual guidance, and/or reduced control complexity. For example, they would extend fingers that were not in contact with the object, or fold these fingers into the palm of the hand. Variability in hand postures was increased in deafferented participants, particularly for smaller objects. Our findings provide new insights into how the complex control required for whole hand actions is compromised by loss of haptic feedback, whose contribution is, thus, highlighted.


Assuntos
Retroalimentação Sensorial/fisiologia , Mãos/fisiopatologia , Destreza Motora/fisiologia , Postura/fisiologia , Propriocepção/fisiologia , Transtornos das Sensações/fisiopatologia , Percepção do Tato/fisiologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Sensors (Basel) ; 19(11)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163579

RESUMO

The application of tactile-based wearable devices to assist in navigation for people with low sight/low memory has demonstrated the feasibility of using such devices as a means of communication. Accordingly, a previous study in construction research investigated various parameters of tactile signals to develop a communicable system for potential application in construction hazard communication. However, the nature of construction limits the application of such devices to the body of construction workers, and it is important to understand sensor design parameters for improved communication, which has not been given significant attention yet. Therefore, this study aims to determine key design factors such as the number of motors, spacing between sensors and the layout of a tactile sensory system to be used for communicating construction hazards to workers. For this purpose, this study focused on identifying the number of motors based on extensive literature and the problem of construction safety as to hazard communication, determining the arrangement that allowed for effective delivery and perception of information with minimum effort. The researchers conducted two experimental studies: First, to determine the minimum spacing between vibration motors that allows for the identification of each individual motor with high accuracy; and second, to determine the layout of motors that is suitable for effective communication of multiple types of information. More importantly, the tactile-sensor configuration identified from this study allows the workers to learn the signal patterns easily in order to identify multiple types of information related to hazards. Using such a communication system on construction sites will assist in transmitting hazard-related information to workers, and thus, protect the lives of workers. Such wearable technologies enable the detection of individual-level hazards and prevent worker fatalities and severe injuries.


Assuntos
Técnicas Biossensoriais , Percepção do Tato/fisiologia , Dispositivos Eletrônicos Vestíveis , Humanos , Tato/fisiologia , Vibração , Local de Trabalho
17.
PLoS One ; 14(5): e0217200, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31112590

RESUMO

Children with Attention-Deficit Hyperactivity Disorder (ADHD) struggle to perform a host of daily activities. Many of these involve forceful interaction with objects and thus implicate dynamic touch. Therefore, deficits in dynamic touch could underlie functional difficulties presented by ADHD children. We investigated whether performance on a dynamic touch task (length perception by wielding) differ between children with ADHD and age-matched controls. We further examined whether this difference could be explained by fractal temporal correlations (wielding dynamics). Forty-two children (ADHD: 21; typically developing: 21) wielded unseen wooden rods and reported their perceived length in the form of magnitude productions. The rods varied in the magnitude of the first principal moment of inertia (I1). Three-dimensional displacements of hand and rod positions were submitted to Detrended Fluctuation Analysis to estimate trial-by-trial temporal correlations. Children with ADHD reported shorter length for rods with higher I1 than their typically developing peers, indicative of reduced sensitivity to mechanical information supporting dynamic touch. Importantly, temporal correlations in wielding dynamics moderated children's usage of I1. This finding points to a role of exploratory movements in perceptual deficits presented by children with ADHD and, thus, should be considered a new potential target for interventions.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Fractais , Atividade Motora/fisiologia , Percepção do Tato/fisiologia , Percepção de Peso/fisiologia , Criança , Feminino , Humanos , Masculino , Desempenho Psicomotor
18.
Exp Brain Res ; 237(7): 1773-1779, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31037326

RESUMO

Whether visible or not, knowing the location of our hands is fundamental to how we perceive ourselves and interact with our environment. The present study investigated perceived hand location in the absence of vision in 30 participants. Their right index finger was placed 10, 20 or 30 cm away on either side of the body midline, with and without their left index finger placed 10 cm to the left of the right index. On average, at each position, participants perceived their right hand closer to the body midline than it actually was. This underestimation increased linearly with increased distance of the hand from body midline [slope 0.77 (0.74 to 0.81), mean (95% CI)]. Participants made smaller errors in perceived hand location when the right hand was in the contralateral workspace [mean difference 2.13 cm (1.57 to 2.69)]. Presence of the left hand on the support surface had little or no effect on perceived location of the right hand [mean difference [Formula: see text] cm ([Formula: see text] to 0.02)]. Overall, participants made systematic perceptual errors immediately after hand placement. The magnitude of these errors grew linearly as the hand got further away from the body midline. Because of their magnitude, these errors may contribute to errors in motor planning when visual feedback is not available. Also, these errors are important for studies in which perceived hand location is assessed after some time, for example, when studying illusions of body ownership and proprioceptive drift.


Assuntos
Mãos/fisiologia , Ilusões/fisiologia , Ilusões/psicologia , Propriocepção/fisiologia , Percepção do Tato/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino
19.
Elife ; 82019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31042148

RESUMO

The concept of objects is fundamental to cognition and is defined by a consistent set of sensory properties and physical affordances. Although it is unknown how the abstract concept of an object emerges, most accounts assume that visual or haptic boundaries are crucial in this process. Here, we tested an alternative hypothesis that boundaries are not essential but simply reflect a more fundamental principle: consistent visual or haptic statistical properties. Using a novel visuo-haptic statistical learning paradigm, we familiarised participants with objects defined solely by across-scene statistics provided either visually or through physical interactions. We then tested them on both a visual familiarity and a haptic pulling task, thus measuring both within-modality learning and across-modality generalisation. Participants showed strong within-modality learning and 'zero-shot' across-modality generalisation which were highly correlated. Our results demonstrate that humans can segment scenes into objects, without any explicit boundary cues, using purely statistical information.


Assuntos
Aprendizagem/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Percepção do Tato/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , /fisiologia
20.
Neurosci Lett ; 705: 131-137, 2019 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-31042570

RESUMO

An event-related decrease in alpha power contralateral to the presentation of a stimulus is now a well-established phenomenon. Two distinct accounts of the functional role of alpha changes are present in the literature that either focus on alpha changes observed during attentional or simple perceptual tasks. This study directly compares tasks that invoke alpha decreases during exogenous, endogenous and perceptual processing. Using a data driven approach to compare alpha changes we show that alpha decreases differ only between exogenous and endogenous attention tasks for only a short time window, 500-600 ms after cue onset. We suggest this indicates a role for alpha in voluntary orientating and stimulus predictability.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Percepção do Tato/fisiologia , Adulto , Sinais (Psicologia) , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
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