Presentation Information
[P1-39]Unconscious motor–visual temporal recalibration occurs in both active and passive movements
*Masaki Tsujita (Faculty of Child Studies, Kamakura Women’s University )
Keywords:
temporal lag adaptation,sensorimotor adaptation,method of constant stimuli,Arduino,cerebellum
Simultaneity judgments between motor actions and visual flashes are adaptively recalibrated after repeated exposure to a motor–visual temporal lag. It remains unclear whether this recalibration is specifically attributed to the temporal processing of an intersensory pair (e.g. tactile–visual) or to the temporal processing of the causal relationship between active movements and sensory outcomes. A previous study reported that motor–visual simultaneity judgments are recalibrated even when observers are unaware of the adapted temporal lag. We examined whether this unconscious temporal recalibration also occurs in passive movements. Given that self-generated sensory outcomes are automatically distinguished from externally generated sensory events on the basis of the temporal prediction by an efference copy, we predicted that unconscious temporal recalibration would require active movements. Participants were randomly assigned to either of two groups: in the active movement group, participants actively pressed a key; in the passive movement group, a DC solenoid moved their finger up and down as if pressing a key. Adaptation flashes were presented with a 0 ms lag in the first half and a 150 ms lag in the second half of the session. After the experiment, participants were asked whether they were aware of the temporal lag in the second half. Contrary to our prediction, among participants who were unaware of the temporal lag, the point of subjective simultaneity between movements and visual flashes shifted significantly in response to the adapted temporal lag, regardless of whether the movements were active or passive. These results suggest that an automatic temporal recalibration system is implemented in the temporal processing of both intersensory pairs and action–outcome relationships.