Transcranial direct current stimulation modulates shifts in global/local attention.

The effects of transcranial direct current stimulation on global/local attentional switching and feature processing were assessed. Direct current stimulation was applied to the left posterior parietal cortex in 14 healthy participants. A compound letter task was used to probe the feature processing and the switching of attention between global and local features. Results indicate that cathodal stimulation acutely degraded attentional switches during stimulation, and anodal stimulation persistently degraded local-to-global attentional switching for at least 20 min after stimulation. Direct current stimulation had no significant effects on global/local feature processing. These results support the functionality of left parietal cortex in attentional switch and represent the first successful modulation of global/local switching using exogenous brain stimulation.