Cortical spindles at the SWS/REM transition correlate with CaMKII phosphorylation in the hippocampus.
(A) Raw LFP recordings of representative SWS animal (top trace) classified according to state (colored hypnogram). Cortical spindles before (middle trace) and after band-pass filtering in the spindle range (bottom trace). (B) Same as (A) for representative REM animal. (C) Spectral map of representative SWS animal, depicting sleep-wake cycle with state clusters and borders. Cortical spindles marked as circles of size proportional to duration, color-coded by hypnogram. (D) Same as (C) for representative REM animal. (E) Cortical spindle counts and hippocampal pCaMKIIα were significantly correlated in the REM group when all spindles were considered (R2 = 0.484, p = 0.0375), i.e. pooled from SWS and IS. No correlation was observed during SWS only (R2 = 0.116, p = 0.369) or IS only (R2 = 0.007, p = 0.825). No correlation was observed in the SWS group for SWS+IS (R2 = 0.00003, p = 0.999), SWS only (R2 = 0.006, p = 0.849) or IS only (R2 = 0.052, p = 0.5560). Plots include both exposed and control animals. See also S1, S2 Figs.