Localization of the human frontal eye fields and motor hand area with transcranial magnetic stimulation and magnetic resonance imaging

We localized the neuroanatomical correlates for control of saccadic eye mov ements and for finger movements using a combined transcranial magnetic stim ulation (TMS) and magnetic resonance imaging (MRI) approach. Two participan ts underwent TMS while performing an endogenous saccade task. The motor han d area was localized by TMS and the region anterior to it was mapped to ide ntify the borders of a region where TMS produced delays in generating contr alateral saccades. MRI scans were then obtained with fiducial markers place d over the motor hand area and 2 cm anterior to it, the common cortical reg ion that produced saccadic delays in these two subjects. It was also shown that the structural anatomy of the hand area, physiologically defined by vi sible contractions of the contralateral hand following TMS, corresponded to the knob-like structure recently reported [18, 19]. These results demonstr ate that TMS can be a precise, non-invasive tool for neuroanatomical mappin g of cortical structures when combined with structural images of the brain. (C) 1999 Elsevier Science Ltd. All rights reserved.