Dorsal stream activity and connectivity associated with action priming of ambiguous apparent motion

Theories proposing a bidirectional influence between action and perception are well supported by behavioral findings. In contrast to the growing literature investigating the brain mechanisms by which perception influences action, there is a relative dearth of neural evidence documenting how action may influence perception. Here we show that action priming of apparent motion perception is associated with increased functional connectivity between dorsal cortical regions connecting vision with action. Participants manually rotated a joystick in a clockwise or counter-clockwise direction while viewing ambiguous apparent rotational motion. Actions influenced perception when the perceived direction of the ambiguous display was the same as manual rotation. For comparison, participants also rotated the joystick while viewing non-ambiguous apparent motion and in the absence of apparent motion. In a final control condition, participants viewed ambiguous apparent motion without manual rotation. Actions influence on perception was accompanied by a significant increase in alpha and beta band event related desynchronization (ERD) in contralateral primary motor cortex, superior parietal lobe and middle occipital gyrus. Increased ERD across these areas was accompanied by an increase in gamma band phase locking between primary motor, parietal, striate and extrastriate regions. Similar patterns were not observed when action was compatible with perception, but did not influence it. These data demonstrate that action influences perception by strengthening the interaction across a broad sensorimotor network for the putative purpose of integrating compatible action outcomes and sensory information into a single coherent percept.