Figure 7

The branching parameter σ was estimated using the avalanche approach across 1000 frames of generalised seizure periods in 10 frame bins. 2 datasets were excluded based on the absence of clear transitions from non-generalised to generalised activity, or insufficient frames following the transition initiation. σ remains close to 1 in the leadup to the generalised seizure and drastically increases as dynamics become highly synchronous, for most datasets (2, 3, 4, 5, 7, 8). Interestingly, following initial increases, σ quickly returns to ~ 1 while high synchrony is ongoing. Note that for some datasets (1, 6) σ remains close to 1 until after the onset of highly synchronous activity. Oscillatory dynamics following the peak of synchronous activity are characterised by moderate increases in σ above 1 (3, 7).