Article Figures & Data
Figures
- Figure 1.
The firing pattern of theta clock-spiking cells. A, A firing rate histogram of a theta clock-spiking cell from a 2000 s recording (top) and a power spectrogram of the corresponding hippocampal CA1 LFP (bottom). The colored bar at the bottom indicates various behavioral states. B, A zoomed-in representation of the REM sleep state from above. Note a theta rhythmic clock-like firing pattern. Scales: theta, 0.3 mV; LFP, 0.5 mV; time, 1 s. C, ISI histograms of the cell during 20 s of the waking exploration state (left) and 20 s of the REM sleep state (right). Note the Gaussian distribution in both. Insets are autocorrelograms. D, Significant differences between the average firing rates of the theta clock-spiking cells and the peak frequencies of the power spectra of the corresponding LFP theta. Error bars represent the SD. *p < 0.05, **p < 0.01; for waking exploration, n = 5; for REM sleep, n = 4. fre., Frequency.
- Figure 2.
The other four theta clock-spiking cells. A–D, Each panel represents one cell. Left panels show the firings of theta clock-spiking cells during waking exploration state. Scales: theta, 0.2 mV; LFP, 0.4 mV; time, 1 s. Right panels show firing rate histograms of the cells and power spectrograms of the corresponding hippocampal CA1 LFPs. The colored bars at the bottom indicate various behavioral states. Insets are ISI histograms with Gaussian fitting and autocorrelograms, both during waking exploration state.
- Figure 3.
Spiking properties of four types of CA1 cells. A, ISI distributions of a theta clock-spiking cell, a complex-spiking cell, a theta-locked interneuron, and a theta-unlocked interneuron (top to bottom); insets are the extracellular waveforms (mean ± SD; 500 waveforms were calculated for each cell). ISI bin width, 1 ms. Scales: 0.1 mV, 0.5 ms. B, Autocorrelograms of the corresponding cells in A. Bin widths: 0.5 ms for the complex-spiking cell; 5 ms for the others. C, Spike phase distributions of the corresponding cells in A related to LFP theta oscillations.
- Figure 4.
Classification of four types of cells recorded in CA1. Each symbol represents one cell. x-axis, Durations of extracellular waveforms measured at 1/e negative peak; y-axis, firing rates; z-axis, peak intervals of ISI distributions. Insets, Summary data for firing rate, spike duration, and peak interval of ISI of the four types of neurons. Error bars represent SD. **p < 0.01, ***p < 0.001. For theta clock-spiking cells, n = 5; for theta-locked interneurons, n = 44; for theta-unlocked interneurons, n = 39; for complex-spiking cells, n = 425.
