Abstract
I will present our research on the functional properties of brain structures which are involved in object-directed actions. Specifically, we explore the nature of viewed-action representation using functional magnetic resonance imaging (fMRI). One cortical region involved in action recognition is anterior intraparietal (AIP) cortex. The principal factor determining the response in AIP is the identity of the observed hand. Similar to classical motor areas, AIP displays clear preference for the contralateral hand, during motor action (i.e., object manipulation) without visual feedback. This dual visuomotor grasping representation suggests that AIP may be involved in the specific motor simulation of hand actions. Furthermore, viewing object-directed actions (from an egocentric-viewpoint, as in self action) elicits a similar selectivity for the contralateral hand. However, if the viewed action is seen from an allocentric viewpoint (i.e. being performed by another person facing the viewer), greater activation in AIP is found for the ipsilateral hand. Such a mapping may be useful for imitation of hand action (e.g. finger tapping) made by someone facing us which is more accurate when using the opposite (mirror-image) hand. Finally, using the standard "center-out" task requiring visually guided hand movements in various directions, we show that primary motor cortex (M1) is sensitive to both motor and visual components of the task. Interestingly, the visual aspects of movement are encoded in M1 only when they are coupled with motor consequences. Together, these studies indicate that both perceptual and motor aspects are encoded in the patterns of activity in the cortical motor pathways.
Meeting abstract presented at VSS 2014