Bilateral representation of sequential finger movements in human cortical areas

The spatial distribution of cortical neural clusters activated during movem ent of either hand ('bilateral' population), or only of one hand, was inves tigated in healthy right-handed volunteers performing a sequential finger o pposition task, using echo-planar functional magnetic resonance imaging. 'B ilateral' clusters were found in the mesial premotor, perirolandic and adja cent lateral premotor cortex of the two hemispheres, and in the left superi or parietal lobule. In the precentral gyrus, their spatial extent was large r on the left hemisphere. Clusters activated exclusively during contralater al finger movements were equally distributed in the left and right perirola ndic cortex. No cluster activated exclusively during ipsilateral finger mov ements was detected. These findings support a role of the motor/lateral pre motor cortex of the dominant hemisphere in bilateral motor control. (C) 199 9 Elsevier Science ireland Ltd. All rights reserved.