Figure 5.

Source localization of alpha modulation. A, Beamformer source reconstructions (shown as surface projections on a rendered standard brain) demonstrate that the anticipatory alpha modulation (attention left–right) is maximal in occipital cortex (extending into right parietal cortex). B, AMI for all TMS sites and ROIs. The AMI is defined as (attention contra − ipsi)/(average over all attention and TMS conditions). As for the sensor level data, comparisons of the attentional modulation index (attention contra–ipsi) revealed an interaction of TMS site and hemisphere (source ROI). Significant (p < 0.05) post hoc comparisons are indicated by asterisks, trends (p < 0.1) are indicated by hashes. C, Δ AMI at ROIs in the hemisphere ipsilateral and contralateral to TMS, calculated as for the sensor level data (Fig. 3C). Comparison revealed a stronger effect on alpha modulation contralateral to stimulation (p < 0.05).