Fig. 3: MS neurons show phase coupling to hippocampal tSCs.

a Top, spike triggered averages (STA) of the raw CA1 LFPs of an example MS neuron. Theta cycles were sorted by tSC expression (from left to right, all cycles included, theta cycles expressing tSC1 to tSC5). Arrowheads indicate tSC peaks. Middle, spike triggered spectral power images (STS power) of the CA1 LFP for the same example neuron. Bottom, corresponding spike triggered spectral phase images (STS phase) of the same MS neuron. b Firing pattern of two tSC-coupled example MS neurons (example neuron #2 to tSC1 and tSC2, example neuron #3 to tSC3 and tSC4). Top, average tSC signals. Middle, raster plots of spike times aligned to the most negative trough of the tSC signal within each theta cycle. Bottom, peri-event time histograms (PETHs) corresponding to each spike raster (black; y-axis on the left) and Rayleigh’s Z-value as a function of temporal offset between hippocampal tSCs and MS spike trains (red; y-axis on the right). c Z-scored phase histograms of all tSC-coupled MS neurons, sorted into four groups based on the tSC they are coupled to (blue, low firing rate; yellow, high firing rate). Zero phase corresponds to tSC troughs (white vertical lines). Cells within each group are sorted by their preferred phase in two blocks: top, cells with maximum firing rate before the most negative tSC trough; bottom, cells with maximal firing after the most negative tSC trough. Red arrowheads mark the example neurons from panel (b). d Histograms of preferred tSC phases for all tSC-coupled MS neurons, sorted into four groups based on the tSC they are coupled to. e Left, histogram of the number of tSCs single MS neurons are coupled to. Right, number of neurons phase-coupled to each tSC. f Stacked bar chart showing the proportion of tSC-coupled neurons (empty bars) as a function of their theta-coupling (left) and rhythmic firing properties (right). Source data are provided as a Source Data file.