Dynamic cortical activation in mental image processing revealed by biomagnetic measurement

THE mental rotation task has been reported to activate the human parietal a nd extra-striate areas, based on the results of fMRI and PET analysis. In t he present study, we investigated the dynamic properties of the distributed cortical activity related to mental rotation processes at high temporal re solution by means of brain magnetic field measurements and a linear inversi on algorithm. Distributed neural activities during the mental rotation and control tasks were estimated for six subjects, and the differences in the a ctivity distribution were analyzed. Statistically significant differences i n the parietal and lateral posterior temporal region were detected 200-300 ms after the visual stimulus, indicating that the dorsal and ventral pathwa y were included in the mental image processing. NeuroReport 10:1793-1797 (C ) 1999 Lippincott Williams & Wilkins.