Figure 6.

Parietal spindles phase-lock to hippocampal spindles and modulate hippocampal ripple activity. A, HC-SS phase-locking with NC-SS tends to be localized along the longitudinal axis (A1 vs A2) and prefers ipsilateral HC-NC channel pairs (A3 vs A4). Each panel shows two traces of PLV. Blue trace represents average PLV computed over 3 s trials with overlapping HC-SSs and NC-SSs, centered on the starts of HC-SSs. Black trace represents average PLV computed over an equal number of pseudo-trials centered on random time points in NREM (N2 + N3). Lt, Left; Rt, right. B, PAC between the phase of NC-SS (10–16 Hz) in parietal lobe and the amplitude of HC ripple-range activity (60–120 Hz). Each histogram bin covers 10 degrees of phase. B1, B2, Channels are the same as those in A2 and A4, respectively. C, 2D projection maps of medial (C1) and lateral (C2) NC channels showing significant spindle phase-locking with HC. Each blue circle represents a significant NC channel, with color intensity corresponding to peak PLV amplitude. Plus signs indicate channels with no significant phase-locking. Projection maps that separate left and right hemispheres can be found in Extended Data Figure 6-1.