Biomagnetic measurement of the neural activity in the mental image processing

We investigated the dynamic properties of the distributed cortical activity related to mental rotation processes at high temporal resolution by means of brain-magnetic-field measurements and a linear inversion algorithm. Distributed neural activities during the mental rotation and control tasks were estimated for six subjects, and the differences in the activity distribution were analyzed. Statistically significant differences in the parietal and lateral posterior temporal region were detected 200-300 ms after the visual stimulus, indicating that the dorsal and ventral pathway were included in the mental image processing.