Abstract
Visuospatial motion processing is a critical behavioural function known to involve networks of rapidly activated areas including motion area V5, and spatial attention related areas in parietal cortex. The current experiment sought to investigate the functional chronometry of area V5, mIPS, and pIPS, based on individual fMRI in the performance of the Motion-Driven Attention task. It was hypothesized that TMS of these regions would lead to decreased performance early after motion onset, and then again at approximately 150 ms. Nine participants performed the task during paired-pulse TMS with seven stimulus onset asynchronies between 0 and 180 ms. The task required identification of a stimulus defined by coherent motion moving across one visual quadrant. TMS of V5 did not lead to statistically significant effects, though individual data indicates early activation in most participants. TMS of mIPS led to a relative decrease in performance on the Motion-Driven Attention task at 150 ms, and a trend towards an early decrease at 30 and 60 ms. TMS of pIPS showed a significant decrease in performance at 0 ms which could be interpreted as an interruption of vigilance. The timing found for mIPS is consistent with our previous reports of early and later V5 activation possibly suggesting feedforward/feedback coupling of these areas during processing of motion driven attention.
Meeting abstract presented at VSS 2013