Fig. 3.

The mean spectral coherence (black lines) in the theta and gamma band when data are aligned to the established external solar time. Black bars above the data illustrate the times that the homeroom light (not the recording room light, which was always on) was off according to this alignment; the homeroom light was on at all other times. (A) and (B) show the theta and gamma band coherence between hippocampus and insula, (C) and (D) show the same between hippocampus and anterior cingulate, (E) and (F) show the same between the two cortical regions. As in Fig. 1. the grey envelope represents the 5th and 95th percentile extents of the distribution of values produced by randomly lagging each dataseries against each other dataseries 1000 times.