The role of left and right intraparietal sulcus in the attentional blink: a transcranial magnetic stimulation study

Processing of one visual target (T1) makes it difficult to become aware of a second target (T2), when two targets, embedded in a stream of distractor stimuli, occur within about 500 ms. This phenomenon is known as attentional blink (AB) and reflects the temporal limitation in allocating visual attention. Although several studies suggest that parietal regions are concerned with the AB phenomenon, their functional relevance remains unclear. We investigated whether left and/or right intraparietal sulcus (IPS) contributed to the AB bottleneck using transcranial magnetic stimulation (TMS). The course of recovery from the AB deficit was facilitated when single pulse TMS induced a transient interruption of left or right IPS activity at a T1-TMS stimulus onset asynchrony of 350 ms, while there was no effect of TMS or sham stimulation delivered over Cz with the same timing. These results provide direct evidence that activation of left as well as right IPS is involved in the genesis of AB. This finding supports the idea that the IPS plays a critical role in the cortical network controlling the temporal dynamics of visual awareness.