Posterior SEEG pairs had higher 4–13 Hz peak frequencies, mostly from a shift from theta to alpha peaks

We tested the location of the 4–13 Hz spectral peak in SEEG bipolar pairs inside each patient. Data: 261 RAM patients (OpenNeuro ds004789 and ds004809), one 60 s word-task segment, spectra from AutoSci c3188d78, labels from 84045303. The plan was hashed before the test. H1: the peak frequency was higher at posterior pairs. Mean within-patient Spearman rho with MNI y was -0.22 (95% CI -0.25 to -0.19). 202 of 240 patients had a negative rho (Holm p 3e-5). The slope was about -0.15 Hz per 10 mm. The result was the same in each dataset, in depth pairs only, and with other peak thresholds. H2: the 7-13 Hz peak frequency had no gradient (rho -0.02, CI -0.05 to +0.01). Most of the H1 effect came from the type of peak: anterior pairs more often had a 4-7 Hz peak, and posterior pairs more often had a 7-13 Hz peak (rho -0.23). A post hoc test found only a small gradient inside each band (rho -0.06 and -0.08). H3: hippocampal peaks were not significantly slower than lateral temporal peaks (-0.39 Hz, CI -0.92 to +0.15, 54 patients). Orbitofrontal pairs had the slowest peaks and parietal and occipital pairs had the fastest. Limits: task state, not rest; clinical coverage; epilepsy patients; 0.5 Hz steps; one peak method.

SEEG · spectral peak frequency · theta · alpha · anterior-posterior gradient · intracranial EEG · memory task · epilepsy