Cite as:
Han S, Zhou W, Wang C, 2005, "Human parietal cortex and attentional modulation of visual activities: A combined TMS and ERP study" Perception 34 ECVP Abstract Supplement

Human parietal cortex and attentional modulation of visual activities: A combined TMS and ERP study

S Han, W Zhou, C Wang

Prior brain lesion and neuroimaging studies suggest that human posterior parietal cortex is engaged in guiding spatial attention. However, the precise function of the parietal cortex in attentional modulation of visual activities remains unclear. We applied repetitive transcranial magnetic stimulation (rTMS) to the left or right posterior parietal lobes of healthy adults before recording event-related potentials (ERPs) to the detection of targets in the left or the right visual fields in separate blocks of trials. Relative to a control condition with TMS over the precentral gyrus where sustained spatial attention did not modulate striate activity (C1) but enhanced extrastriate activities (P1 and N1) more in the attended than in the unattended conditions, TMS over the left parietal cortex resulted in enlarged C1 amplitude in the attended more than in the unattended conditions. TMS over the right parietal cortex, however, resulted in a reverse pattern of C1 modulation by attention. TMS over the left parietal cortex also reduced the P1 effect but increased the N1 effect relative to the control condition. The results provide direct evidence for the involvement of human parietal cortex in attentional modulation of the striate and extrastriate activities. Moreover, the role of human parietal cortex in attentional modulation of the visual activities varies as a function of the time courses of visual processing.

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