Visual working memory revealed by repetitive transcranial magnetic stimulation

We evaluated whether repetitive transcranial magnetic stimulation (rTMS) co uld be utilized for studying the hemispheric lateralization and anatomical localization of the cortical areas of the visual system that are concerned with object-related visual working memory. In eight normal volunteers, visu al working memory was tested during rTMS delivery over nine regions in each hemisphere. Visual working memory was significantly disturbed by rTMS over the right hemisphere compared with the left (P < 0.05). The disturbance in visual working memory by rTMS was significant over the right inferior fron tal (F8), inferior temporal (T8), and middle parietal (P4) areas compared w ith the control region (P < 0.05). This study suggests that visual working memory is lateralized to the right hemisphere and localized in the right in ferior frontal, inferior temporal, and middle-parietal areas. As a non-inva sive tool, rTMS may be useful for the functional localization of the workin g memory system. (C) 2000 Elsevier Science B.V. All rights reserved.