Transcranial magnetic stimulation study of temporal aspect of posterior parietal cortex in visual search

In this study, we examined the temporal aspects of the right posterior parietal cortex in easy feature visual search using transcranial magnetic stimulation (TMS). The transcranial magnetic stimulations were applied over the right posterior parietal cortex of the subjects with the TMS onset times were set at 100, 150, 200 and 250 ms after visual stimulus presentation. We found that when TMS stimulus onset asynchronies SOA = 150 ms, compared to the no-TMS condition, there was a significant elevation in response time when TMS pulses were applied. However for the other SOA cases, there was no significant difference between the TMS and no-TMS conditions. Therefore, we considered that the feature search was processed in the right posterior parietal cortex at about 150 ms after stimulation.