Amplitude spectrum of EEG.

<p>Example of EEG (inset) recorded at TO1 from one participant during the 4 s before an un-cued gaze shift from the stimulus sequence on the left to the stimulus sequence on the right (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056428#pone-0056428-g001" target="_blank">Figure 1</a>). Peaks in the amplitude spectrum are evident at the flicker frequencies of the fixated (8 Hz) and non-fixated (12 Hz) stimulus sequences.</p>