Figure 2: Spontaneous behaviour and hippocampal network states.

(A) Illustrations of spontaneous behaviour by a mouse, with periods of immobility (left), grooming (middle), and walking-running behaviour (right). (B) CA1 LFP recording (middle) and the animal speed (heat map) over a 30-s period. (C) Representative ripple event occurring during immobility (*from B, left) and graph of the ripple frequency (right). (D) Raw (black) and filtered (red) theta oscillations recorded during a locomotion epoch (**from B), and a heat map representing the animal speed (left). The frequency-speed (middle, Pearson’s correlation coefficient: r = 0.776, P < 0.05) and power-speed (right, r = 0.755, P < 0.05) relationships are plotted together with their linear fit. (E) Probability distributions of duration, distance, and speed for run epochs (n = 915, 70 sessions, five mice). The median is indicated by a blue line. (F) Graphs of the median speed and speed stereotypy over days (mean ± standard deviation, n = 5 mice, bootstrap, P < 0.05). (G) Graphs showing the distributions of behavioural phases in 70 5-min sessions (cyan: immobility; green: flickering; red: running epochs). ***P < 0.001 (Wilcoxon test). (H) Evolution of spontaneous behaviour between the two first and last days (filled and open circles, respectively) (data are expressed in percentage of the first days as mean +/− sem, n = 5 mice). (I) Illustration of the run epoch pattern diversity in four mice where the red areas correspond to run epochs (left). Inter-individual (black) and intra-individual (gray) variabilities are shown at right (n = 5 mice, n = 7 days, *p < 0.05, Wilcoxon test). (J) Quantification (mean ± standard deviation, n = 5 mice) of the walk-run epoch probability in two 5-min consecutive experimental conditions: light (white) and darkness (black). The first and fourth minutes are labelled with dark and light grey bars, respectively. K. The probability distributions of run epochs in light (white) and dark (black) conditions (left, Wilcoxon test, P > 0.5) and during the first (dark grey) or fourth minute (light grey) of the experimental session (n = 10 sessions, five mice, Wilcoxon test, P < 0.05).