The functional and neural mechanism of action preparation: roles of EBA and FFA in voluntary action control.

Ideomotor theory claims that actions are cognitively represented and accessed via representations of the sensory effects they evoke. Previous studies provide support for this claim by showing that the presentation of action effects primes activation in corresponding motor structures. However, whether people actually use action-effect representations to control their motor behavior is not yet clear. In our fMRI study, we had participants prepare for manual or facial actions on a trial-by-trial basis, and hypothesized that preparation would be mediated by the cortical areas that code for the perceptual effects of these actions. Preparing for manual action induced higher activation of hand-related areas of motor cortex (demonstrating actual preparation) and of the extrastriate body area, which is known to mediate the perception of body parts. In contrast, preparing for facial action induced higher activation of face-related motor areas and of the fusiform face area, known to mediate face perception. These observations provide further support for the ideomotor theory and suggest that visual imagery might play a role in voluntary action control.