Neuroimaging reveals enhanced activation in a reach-selective brain area for objects located within participants'...

In recent years, there has been growing excitement within cognitive neuroscience about the concept of embodiment: How do the capabilities and limitations of our physical bodies affect neural representations in the brain? Neuropsychological and neurophysiological studies show clear evidence that short-term visuomotor experience can influence the encoding of the space around the body in parietal cortex. For example, tool-use may expand the neural representation of peripersonal space. But how is this initial spatial representation influenced by a lifetime of object-related interactions? To examine this question we used functional magnetic resonance imaging (fMRI) to investigate the neural effects of an individual's hand preferences for acting within peripersonal space. Left- and right-handed participants viewed real-world objects at different locations accessible by either the left hand, right hand, or neither hand. The superior parieto-occipital cortex (SPOC), an area most often implicated in reaching actions, showed enhanced visual responses for objects located within the range of space in which each group typically acts. Specifically, in right-handers, who strongly prefer grasping with the right hand, SPOC showed strongest activation for objects located within the range of space for the right hand only. In contrast, in left-handers, who use their two hands comparably often in visuomotor tasks, SPOC showed strongest activation for objects located within the range of space of either hand. These findings show that, even in the absence of overt responses, real 3D objects located in the individual's typical workspace for hand actions automatically invoke enhanced responses in associated visuomotor areas of the brain.