Differentiating intended sensory outcome from underlying motor actions in the human brain

Abstract

To achieve a certain sensory outcome, multiple actions can be executed. For example, unlocking a door might require clockwise or counterclockwise key turns depending on regional norms. Using fMRI in healthy human subjects, we examined the neural networks that dissociate intended sensory outcome from underlying motor actions. Subjects controlled a figure on a computer screen by performing pen traces on an MR-compatible digital tablet. Our design allowed us to dissociate intended sensory outcome (moving the figure in a certain direction) from the underlying motor action (horizontal/vertical pen traces). Using multivoxel pattern analysis and a whole-brain searchlight strategy, we found that activity patterns in left (contralateral) motor and parietal cortex and also right (ipsilateral) motor cortex significantly discriminated direction of pen traces regardless of intended direction of figure movement. Conversely, activity patterns in right superior parietal lobule and premotor cortex, and also left frontopolar cortex, significantly discriminated intended direction of figure movement regardless of underlying direction of hand movement. Together, these results highlight the role of ipsilateral motor cortex in coding movement directions and point to a network of brain regions involved in high order representation of intended sensory outcome that is dissociated from specific motor plans.