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Free keywords:
Self-generated movements; Suppression; Cross-modal; Cerebellum
Abstract:
Sensory consequences of self-generated as opposed to externally-generated movements are
perceived as less intense and lead to less neural activity in corresponding sensory cortices,
presumably due to predictive mechanisms. Self-generated sensory inputs have been mostly
studied in a single modality, using abstract feedback, with control conditions not differentiating
efferent from re-afferent feedback. Here we investigated the neural processing of 1) naturalistic
action-feedback associations of 2) self-generated vs. externally-generated movements, and 3)
how an additional (auditory) modality influences neural processing and detection of delays.
Participants executed wrist movements using a passive movement device (PMD) as they
watched their movements in real time or with variable delays (0-417ms). The task was to judge
whether there was a delay between the movement and its visual feedback. In the externally-
generated condition, movements were induced by the PMD to disentangle efferent from re-
afferent feedback. Half of the trials involved auditory beeps coupled to the onset of the visual
feedback. We found reduced BOLD activity in visual, auditory, and somatosensory areas during
self-generated compared with externally-generated movements, in unimodal and bimodal
conditions. Anterior and posterior cerebellar areas were engaged for trials in which action-
feedback delays were detected for self-generated movements. Specifically, the left cerebellar
lobule IX was functionally connected with the right superior occipital gyrus. The results indicate
efference copy-based predictive mechanisms specific to self-generated movements, leading to
BOLD suppression in sensory areas. In addition, our results support the cerebellum’s role in the
detection of temporal prediction errors during our actions and their consequences.
