Figure 4.

The relationship between sleep and spike spatial distribution. Patient HUP106 is shown. (A) Diagrams of Patient HUP106’s electrodes and the average spike frequency in each electrode for four arbitrarily chosen hour-long segments as indicated by the lines connecting to B. The colour shows which cluster the spikes in the corresponding electrodes were assigned to, based on their location. The brightness represents spike frequency, where brighter colours indicate higher spike rates and whiter colours indicate lower spike rates. (B) Moving average of 1 h of the proportion of spikes in a given cluster. In this patient, the spikes in the red cluster occur predominantly at night. The black dashed vertical lines denote seizures (four seizures are shown). (C) Alpha-delta power ratio over time to estimate sleep epochs. Each time point is the alpha/delta power ratio averaged over a 2000-s bin and averaged over all electrodes. A low alpha/delta ratio indicates relatively higher delta power, suggesting sleep. In this patient, spikes occurring in the red cluster appear predominantly during periods of low alpha/delta power. Supplementary Tables 4 and 5 show the statistics determining the postictal and pre-ictal change in spike spatial distribution for all patients.