SFR rhythms from WT and <i>Kcnma1^−/−</i> SCNs.

<p><i>A</i> and <i>B,</i> MEA recordings from 6 channels on cycle 2 within a WT (<i>A</i>) and a <i>Kcnma1^−/−</i> (<i>B</i>) SCN over 24 hr. Data were smoothed by applying a 1-hr moving window average and plotted to maximize any day-night differences in firing rate. Dotted lines denote CT6 (6 hours after lights on for the animal prior to slice harvest), the daytime peak for SFR. <i>C,</i> Individual firing frequencies from cycle 2. The daytime peak (CT5-7) and trough (CT12–14) SFR values were from 5 WT (<i>n</i> = 32 channels) and 4 <i>Kcnma1^−/−</i> (<i>n</i> = 30 channels) slices±s.e.m. *<i>p</i><0.05.</p

Representative wheel running rhythms from WT and <i>Kcnma1^−/−</i> mice.

<p>Mice were housed on a standard 12 hr light: 12 hr dark cycle for 18 days (light and dark bars above actogram), and then placed in constant darkness (DD) for 25 days (shaded bottom part of actogram). Tick marks denote wheel running and actograms are double-plotted to emphasize the behavioral rhythm. <i>A,</i> The WT mouse has a circadian period of 23.5 hr in DD, and the χ² circadian amplitude of the behavioral rhythm was 2390. <i>B,</i> Representative <i>Kcnma1^−/−</i> actogram (period = 24.2 hr and χ² circadian amplitude = 375).</p

Multi-electrode array recordings of SFR rhythms from SCN.

<p><i>A,</i> Acute SCN slice (300 µm) on probe. Circles outline SCN. OT = optic tract. Electrode spacing = 100 µm. <i>B,</i> Oscilloscope view from slice in (<i>A</i>) showing spontaneous activity at each electrode (channel) on the probe. Red outlines channels within the SCN. 1 box = 2.5 sec/100 µV. <i>C,</i> Six active channels within the SCN showing a robust circadian regulation of the SFR over 40 hr. Light and dark bars indicate the prior entrainment of the animal before slice harvest. <i>D,</i> Perfusion of 1 µM tetrodotoxin (TTX) blocks spontaneous action potentials (2 channels shown). Washout was started 5 min after TTX addition. <i>E,</i> Synchronized rhythms over 3 circadian SFR peaks.</p

SFR rhythms from 3 circadian cycles from WT and <i>Kcnma1^−/−</i> SCNs.

<p><i>A,</i> Representative recordings over 3 cycles from a rhythmic WT (<i>left</i>), a rhythmic <i>Kcnma1^−/−</i> (<i>middle</i>), and an arrhythmic <i>Kcnma1^−/−</i> (<i>right</i>) channel within the SCN. <i>B,</i> Distribution of daily peaks for WT and <i>Kcnma1^−/−</i> SFR rhythms (± s.d.) on each day of recording.</p

Analysis of WT and <i>Kcnma1^−/−</i> SFR rhythms.

<p>Spontaneous activity was analyzed from channels within the SCN that had activity >1 Hz. R = the number of rhythmic channels (in parentheses: average time of the SFR peak±s.d.). AR = the number of arrhythmic channels (% of total). <i>N</i>-values are presented as the number of rhythmic and arrhythmic channels from 5 WT and 4 <i>Kcnma1^−/−</i> slices. Separate <i>n</i>-values (bottom of cell) are presented for peak-to-trough (PT) ratios because these values could not be extracted from every recording due to noise problems. Peak and trough frequencies were determined by averaging two hours of continuous raw data from rhythmic channels at CT 5–7 and CT 12–14, respectively. The PT ratio was calculated for each channel as (P–T)/P and is presented as the average±s.d. ^{*, #, §, †}<i>p</i><0.05.</p