Figure 2.

Transient increases in the spectral power of LFPs. A, Raw, unsmoothed spectrograms of a single LFP recording. Each plot corresponds to the target interval indicated on the left. The vertical axis is the frequency of the oscillatory activity, and the horizontal axis is the time during the performance of the task. Gray vertical bars represent the times at which the monkey tapped on the push-button. All the spectrograms are aligned to the last tap of the synchronization phase (red vertical bar). Top, Light-blue and gray horizontal bars represent the synchronization and continuation phases, respectively. Each spectrogram is the average of 5 trials. B, Close-up of the C2 intertap interval of the 1000 ms plot in A, showing that transient power increases occurred in the β-band. C, Spectrograms of a different LFP recording showing transient power increases in a larger frequency than in A. D, Close-up of the C1 intertap interval of the 1000 ms plot in C showing that the transient power increments occurred in the γ-band.