Fig. 6: Electrophysiological and behavioral changes tens of seconds before seizure initiation.

a Mean spectrogram of frontoparietal electroencephalogram (EEG) over 120 s prior to seizure initiation in the sustained motivated licking paradigm. Warm colors indicate higher values and cool colors lower values. Mean power (dB) in the 120 s to 1 s time period prior to each seizure was divided by mean power over the same time period for each frequency in the spectrogram, and log tranformed (10 × log₁₀) as described in the Methods. The resulting spectrograms were averaged across seizures within each animal (26,935 seizures total) and then across animals (n = 27 animals). b Time courses of power in low (0–39 Hz) and high (40–500 Hz) frequency bands before seizure, using the same data as a. c Mean lick rate over 120 s prior to seizure initiation in sustained motivated licking paradigm (n = 27 animals, 26,935 seizures). d Somatosensory cortical (purple colors) firing rate and rhythmicity index (in 2 s bins) in the 120 s around seizure initiation and termination (n = 165 cells, 21,866 seizures), showing gradual decrease in firing rate from −80 to −10s before seizure onset (p = 0.005), and gradual increase over the same period in cortical rhythmicity (p = 1.87 × 10⁻⁶). e Ventrobasal thalamic (green colors) firing rate and rhythmicity index (in 2 s bins) in the same time periods (n = 163 cells, 10,676 seizures) showing a gradual decrease in firing rate from −80 to −10s before seizure onset (p = 9.2 × 10⁻⁸) but no change over this period in rhythmicity (p = 0.56). Values are expressed as mean ± standard error.