Neural adaptation and fractional dynamics as a window to underlying neural excitability
Fig 6
Power spectra changes related to the seizure onset zone and increased adaptation.
(a) Previously published invasive EEG power spectra from 8 patients (left panel) [35] and 83 patients (right panel) [36] showing decreased low frequency activity and increased high frequency activity near the seizure onset zone (SOZ) compared to the non-SOZ. (b) Similar shapes can be obtained from constant input models (with one low-pass timescale to approximate membrane filtering) when more negative feedback is present (e.g., increased α or A), implemented either via fractional dynamics (left panel; α = 0.3, g = 0.7 or α = 0.1, g = 1; for both k = 100, τm = 0.3 s) or multiple timescales (right panel; A1 = A2 = A3 = 1.1, g1 = g2 = g3 = 1.3 or A1 = A2 = A3 = 1.5, g1 = g2 = g3 = 1.5; for both τ1 = 0.05 s, τ2 = 0.5 τ3 = 5 s, k = 500,τm = 5 s).