Contribuição das aferências visuais e somatossensoriais na predição da ação

Abstract

Studies have shown that cortical reorganization within the central nervous system can be modulated by peripheral variables, such as upper limb immobilization for a period of 10 hours. However, the behavioral consequences of this reorganization on action prediction remain poorly understood. In the present study, the right upper limb of twelve healthy individuals was immobilized for 10 hours using a sling and an immobilizing glove. The study was approved by the local ethics committee (6.892.803). After the immobilization period, participants observed psychophysical videos depicting handobject contact on a computer screen. In half of the videos, 50% of the final movement trajectory was occluded, whereas in the other half the trajectory remained fully visible. Participants were instructed to press the space bar to predict the moment of contact between the hand and the object. One week later, the same participants repeated the experimental protocol without immobilization. Constant error (CE), defined as the mean difference between the participant’s response and the actual hand-object contact time, and variable error (VE), defined as the variability of temporal responses, were calculated. Repeated-measures ANOVA was used to compare CE and VE according to somatosensory condition (immobilized vs. free), visual condition (full vision vs. occluded vision), and laterality (right vs. left). The results revealed no significant effects of somatosensory condition, visual condition, or laterality on constant error. For variable error, a significant effect was observed only for visual condition, with greater variability of estimates in the occluded vision condition compared to the full vision condition. No significant interactions were found among the analyzed variables. These findings suggest that action prediction is preserved following upper limb immobilization, indicating that transient somatosensory alterations are insufficient to impair the accuracy of temporal estimates. In contrast, the availability of visual information appears to primarily influence the consistency of action prediction, increasing response variability when the movement trajectory is partially occluded.