FIG. 2.

Relationship between behavioral and network states. A, top and middle panels: time course of average relative power in the gamma band of a visual cortex local field potential (LFP, y-axis) across trials (x-axis) in which a monkey showed fast and slow reactions to a sudden visual change taking place within the receptive field of neurons simultaneously recorded from the same electrode. The 0 time point in the x-axis shows when the stimulus change occurred. The top panel shows the relative LFP power when the changing stimulus was the focus of the monkey's attention, whereas the middle panel represents the power induced when it was meant to be ignored. In each, the solid line shows LFP power for trials with fast reaction times (i.e., when attention was allocated most effectively) and the dashed line shows power for trials with slow reaction times (those when attention was less effective); the gray-shaded area shows significant differences between those two trial types. Gamma power predicts faster reactions to attended stimuli and slower reactions to unattended stimuli. Bottom: Z-score of correlation coefficients across monkeys and recording sites for LFP power vs. reaction times, showing that higher gamma power predicts faster performance (i.e., smaller reaction times). B: correlation between μ oscillations and reaction times in rat engaged in a tasting session. Top trace: session-long recording trace of a single cortical LFP, showing a general change at 71 min into the session; below, two 2-s-long traces, one from early in the session and one from late, showing in detail the emergence of μ rhythms late in the session. Bottom: the 2 bars show the amount of μ rhythms in and after the 1st h; the points overlaid on the bars show the reaction times of the first purposeful orofacial movement in response to a taste stimulus. Note the correlation with μ rhythms. A modified with permission from Womelsdorf et al. (2006); B from Fontanini and Katz (2005).