Figure 2.

Adapted from Worden et al. (2000). (A) Task schematic. At the start of each trial, participants were presented with a central arrow cue that instructed them to attend to the left or right hemifield. Following a 1-s cue-target interval, a stimulus was presented at either the left or right location. Participants were charged with making a difficult orientation or motion discrimination of stimuli occurring at the cued location, while ignoring all events at the uncued location. Participants maintained central fixation throughout the trial. (B) Dorsal view (nose at top) of the electrode layout. Electrodes used for statistical analysis are plotted in red, circled electrodes were used to generate the accompanying waveforms. (C,D) ERPs to the lower left and right cues (collapsed across motion and orientation trials) for two occipital electrode sites, averaged over 10 subjects. Data for attend lower left are plotted in green, and data for attend lower right are plotted in red. (E,F) Corresponding alpha-band (8–14 Hz) TSE waveforms for the same electrodes. A sustained divergence in TSE amplitude is seen starting at ∼500 ms, which depends on both the cued direction of attention and the side of recording. TSE amplitudes are larger over occipital cortex ipsilateral to the direction of attention.