Voluntary actions modulate perception and neural representation of action-consequences in a hand-dependent manner

Evoked neural activity in sensory regions, and perception of sensory stimuli, are modulated when the stimuli are the consequence of voluntary movement as opposed to an external source. It has been suggested that such modulations are due to efference copies of the motor command that are sent to relevant sensory regions during voluntary movement. Given the anatomical-functional laterality bias of the motor system, it is plausible that the pattern of such behavioral and neural sensory modulations will exhibit a similar bias, depending on the effector that was used to trigger the stimulus (e.g. right / left hand). Here we examined this issue in the visual domain using behavioral and neural measures (fMRI). Healthy participants judged the relative brightness of identical visual stimuli that were either self-triggered (using right or left hand button presses), or triggered by the computer. By presenting stimuli to either the right or left visual field, we biased visual-evoked responses to left / right visual cortex. We found stronger perceptual modulations when the triggering hand was ipsi (rather than contra) lateral to the stimulated visual field. At the neural level, we found that despite identical physical properties of the visual consequence, evoked fMRI responses in right and left visual cortices differentiate the identity of the triggering hand (left / right). Our findings support a model in which voluntary actions induce sensory modulations that follow the anatomical-functional bias of the motor system.