Fig 2: No significant differences in presynaptic glutamate release probability between CS and SD are found in either control or Mef2c-cKOCamk2a-Cre mice.(A and C) Representative paired-pulse recordings of excitatory postsynaptic currents (evoked EPSC) evoked in layer 2/3 pyramidal neurons by two brief electrical stimulations of axon terminals in layer I, 50 ms interval, obtained for three different experimental sleep/wake conditions (CS, SD, RS) imposed on Mef2cf/f mice (A) and Mef2c-cKOCamk2a-Cre mice (C), respectively. The probability of presynaptic release (Prelease), is inversely proportional to the ratio of EPSC amplitudes (1/Prelease ~ P2/P1); The P2/P1 ratio, obtained for three different experimental sleep/wake conditions (CS, SD, RS) and calculated separately for three different inter-pulse intervals (20, 50 and 100 ms), in Mef2cf/f (B) vs. Mef2c-cKOCamk2a-Cre mice (D). The plots (see Materials and methods, numbers of experiments for each sleep/wake conditions shown underneath boxes), show no significant differences between CS and SD conditions in either control or in Mef2c-cKOCamk2a-Cre mice.

Fig 3: Schematic of Mef2c genomic DNA sequence to illustrate locations of knockin sequences of loxP and their recombination product used in this study.

Fig 4: Mef2c+/- mice resolve sleep need in undisturbed conditions but lack a rebound increase of SWS-SWA power in response to sleep loss.(A,B) Average SWA power per 10 s epoch decreases during the sleep phase (ZT = 0 to 12 hr) to the same extent for Mef2c+/+ (n = 6) and Mef2c+/- (n = 6) mice (C). (D) Twenty-four hour average waking SWA power is greater for Mef2c+/- mice. (E) Decay of SWA power (normalized to the average 24 hr waking SWA) during an average SWS episode is preserved in the Mef2c+/- mice but with an increased t, associated with increased sleep need. (F, G) Rebound increased SWS-SWA in response to SD is absent in Mef2c+/- mice. The SD was administered in repeated 6 hr cycles of 4 hr SD and 2 hr RS. (H) A table showing responses of Mef2c-cKOCamk2a-Cre and Mef2c+/- compared to their respective controls (see Figure 5).

Fig 5: Conditional Mef2c knock-out in forebrain excitatory neurons eliminates sleep/wake remodeling of synaptic excitatory inputs to pyramidal neurons in anterior cingulate cortex slices.(A, G) Representative recordings of miniature excitatory postsynaptic current (mEPSC) traces (20 s, left panels, and expanded 1 s traces on the right corresponding to time bars underneath original traces) obtained for three different experimental sleep/wake conditions, CS (green), SD (red), and RS (blue), for Mef2cf/f mice (A) and Mef2c-cKOCamk2a-Cre mice (G). (B,C,D) and (H,I,J) illustrate mEPSC functional parameters obtained from Mef2cf/f and Mef2c-cKOCamk2a-Cre (number of cells for each condition shown above X axis condition label; also see Figure 6—figure supplement 1 for comparison to WT). Averaged cumulative probability histograms for instant frequency and peak amplitude show increased frequency and amplitude with SD compared to CS or RS for Mef2cf/f (E, F) but not for Mef2c-cKOCamk2a-Cre mice (K, L). See Materials and methods and Supplementary file 6 for details and statistics.