Fig. 3.

Discharge of S-max-active MCH−/VGAT+ cell across sleep-wake states. (A) Data from Nb-labeled unit (c103u01, also shown in Fig. 1A–C) showing the sleep-wake recording scored per 10 sec epochs for sleep and wake stages along with simultaneous EEG frequency and amplitude (μV/Hz with frequency on y axis and amplitude differentially scaled according to color from blue to red, over the low frequency, 0–30 Hz from ~0–100 μV, and the high frequency, 30–60 Hz from ~0–25 μV), EMG amplitude (arbitrary units) and unit spike rate (Hz) over the recording session. Note that the unit discharged at moderately low rates during both aW (showing high EMG activity; periods indicated by red dashed vertical lines) and PS (showing low EMG activity; periods indicated by solid green vertical lines), and at its highest rates during SWS. Across stages, its discharge rate was significantly, positively correlated with delta EEG (r = 0.34). Horizontal lines (marked as 1, 2 and 3) indicate 10 sec recording epochs of aW, SWS and PS respectively shown in C. (B) Bar graph showing mean spike rate (Hz) of the unit across sleep-wake stages. Note that the unit fired at a relatively low rate during aW (7.27 Hz), increased its rate through qW, tSWS to reach its maximal rate during SWS (13.35 Hz) and decreased its rate slightly during tPS to reach a lower rate during PS (9.95 Hz). C, Polygraphic records from 10 sec epochs (indicated in A) of the unit together with EEG and EMG activity during aW (1), SWS (2) and PS (3). Note that during waking, despite an overall moderate discharge rate, the unit notably slows down its firing during active periods when EMG activity was prominent (C1). It fired continuously and tonically in single spikes during SWS (C2), with an instantaneous firing frequency of 14.9 Hz. It discharged also at moderate rates during PS (C3). Calibrations: horizontal, 1 s; vertical, 1 mV (EEG, EMG), 2 mV (unit). Abbreviations: OB, olfactory bulb; PF, prefrontal cortex; RS, retrosplenial cortex.