Movement preparation and motor intention

This paper addresses the functional anatomy of movement representation. We have used associative visuomotor tasks with instructed delays to elicit mot or preparatory activity. We regard such activity, when independent from tra nsient stimulus-locked responses, as a likely candidate for the neural basi s of movement representation (M. Jeannerod, The Cognitive Neuroscience of A ction. Blackwell, Oxford, 1997), In a first event-related fMRI experiment, we found that preparing to move according to arbitrary visuomotor associati ons relies not only on parietofrontal circuitry, but also on portions of th e posterior superior temporal sulcus. In a separate behavioral experiment, we discarded the hypothesis that such activities were confounded by working memory processes. In a second imaging experiment, we have further defined the relative contributions of these parietal, premotor, and temporal areas to the preparatory process and their involvement in motor representations. We conclude that posterior parietal cortex is interested in evaluating the potential motor significance of sensory stimuli, irrespectively of the like lihood of providing a response ("motor intention"). Conversely, preparatory activity in frontal premotor regions appears to be a function of the proba bility of a subsequent movement. Finally, on the basis of the present and p ublished data, we suggest that posterior temporal cortex might be involved in the extraction of contextual and intentional cues during goal-oriented b ehavior. (C) 2001 Academic Press.