Aftereffects of Delay Adaptation in Visual and Tactile Duration Reproduction

Abstract

AbstractProducing brief actions often involves multiple temporal cues that might not always synchronize with each other. In a basic action-effect relationship, the effect is often delayed. How our brain incorporates this delay across different modalities in a sensorimotor close-loop action is less known. To investigate this, we conducted two experiments centered on duration reproduction with delayed sensory feedback. Participants were asked to reproduce a duration, either in visual modality (Experiment 1) or in tactile modality (Experiment 2). During the adaptation phase, an action’s resulting effect, either visual or tactile stimulation, was delayed for 150 ms but stopped simultaneously with the action in one session, while in the other control session it was synchronized. In the subsequent test phase, various action-effect delays, ranging from 0 to 150 ms, were introduced. Our findings revealed that the reproduced durations during the test phase were influenced by both delay adaptation and the varying action-effect delays. Adaptation to the delayed sensory feedback generally shortened the reproduction, which was more pronounced with tactile than visual feedback. Additionally, compared to visual sensory feedback, reproduction using tactile feedback placed more trust on the tactile cue, resulting in a steeper rise in motor reproduction duration as the feedback delay increased. Furthermore, introducing these delays during the test phase also progressively lengthened the prior representation of the standard duration. Our findings thus suggest that the temporal delay adaptation is shaped by the sensorimotor integration. This integration operates based on the sensorimotor reliability, and the weights vary across modalities, with a higher weight on the tactile modality than the visual modality.