Fig. 6.

Spike-field coherence. Time-frequency representations showing spike-field coherence within each of the recorded regions (showing significant time-frequency samples only). Significant SFC was observed in the α-band in all regions, as revealed by cluster-based randomization statistics vs. shuffled data [P < 0.001, corrected for multiple comparisons (Methods)]. Normalized firing rate is plotted on top (black line) (in arbitrary units, averaged over all sessions). Coherence in the α-band was strongest during baseline (t = -1–0 s) and the retention period (t = 0.5–3.5 s), whereas it dropped off during the stimulus (f1, t = 0–0.5 s; f2, t = 3.5–4 s) and decision periods (t = 4–7 s). Strong α-band coherence was accompanied by a low spike-firing rate.