Beta activity increases in the primary visual cortex during attention trials.

<p>A. Stimulus-driven paradigm (cat B, Cx 17/1, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145379#pone.0145379.t001" target="_blank">Table 1</a>). Left: mean FFT spectra obtained from all correct trials during the three experimental days after the behavioral criterion was reached. The visual (gray) and auditory (black) means were obtained by averaging respectively 820 and 760 spectra of 1.28 s long data epochs (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145379#sec002" target="_blank">Methods</a> for details). Right: comparison of the mean spectrum from the correct visual trials (gray; same as in the left panel) with the mean FFT from 90 epochs from incorrect trials (black). B. Anticipatory paradigm (cat E, Cx 17/2). The recorded signals were subjected to the same analysis as in A. Means were obtained from 748 and 765 spectra for correspondingly correct visual and correct auditory trials, and from 320 spectra for incorrect visual trials. In A and B, the shading around the FFT spectra indicates the SEM. The lines above the horizontal axes denote the frequencies at which significant differences were found between the spectra from the correct visual and auditory (left) or correct and incorrect visual (right) trials (Student's t-tests with FDR correction for multiple comparisons, see the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145379#sec002" target="_blank">Methods</a> section; P ≤ 0.05). An example of filtered (16–24 Hz) beta signals recorded from cat B at the beginning of two correct stimulus-driven visual and auditory trials (right and left panel, respectively) performed on the second day after the cat reached the behavioral criterion. The consecutive horizontal lines in each panel represent a continuous signal. The vertical lines separate the final part of the signal corresponding to the inter-trial period preceding stimulus onset and the start of the stimulus presentation during the trial.