Extended Data Fig. 2: Simulated effect of interictal spiking on amplitude- and phase-based measurements of ECoG signal.

(a) Verum baseline interictal ECoG recording free of interictal spiking. (b) Measures of functional connectivity based on amplitude correlation, generalized coherence, and phase coherence. (c) Baseline recording corrupted by the addition of a single burst of interictal spikes to two channels. (d) Addition of the burst corrupted the amplitude and generalized coherence measurement as compared to baseline. No change was observed for the metric of connectivity based on phase coherence. (e) Baseline recording corrupted by the addition of an interictal spike train to two channels. (f) Addition of a spike train corrupted the amplitude and generalized coherence measurement as compared to baseline. No change was observed for the metric of connectivity based on phase coherence. Phase-based measures exhibit robust insensitivity to spike-driven amplitude shifts in the signal and may provide a more reliable estimate of connectivity in the presence of interictal spikes than amplitude correlation and generalized coherence.