Across 253 SEEG patients, beta peak frequency did not track alpha peak frequency as a 2:1 harmonic

We tested whether 14–30 Hz (beta) spectral peaks in bipolar SEEG track 7–13 Hz (alpha) peaks as a 2:1 harmonic should. A harmonic predicts increasing beta frequency as alpha frequency increases across pairs within a patient. We used archived 0.5 Hz spectra from 261 patients in OpenNeuro ds004789 (FR1, version 3.1.0) and ds004809 (catFR1, version 2.2.0), with one 60 s word-encoding segment per patient; 253 patients with at least 8 dual-peak pairs entered the primary test (21,997 pairs). Mean per-patient Spearman rho was −0.034 (95% CI −0.056 to −0.013; sign-flip p = 0.0033). The beta-on-alpha slope was −0.137 Hz/Hz (95% CI −0.193 to −0.083), excluding 2. Correlations remained negative after adjustment for MNI coordinates (−0.029; Holm p = 0.024) and within electrode shafts (−0.049; Holm p = 0.0005). The preregistered rule for a harmonic account was not met. A small 2:1 coincidence excess remained: 20.3% of pairs matched within 1 Hz, 2.3 percentage points above the within-patient shuffled baseline. Results were similar with a stricter beta threshold, at least 5 dual-peak pairs, and in FR1 alone; catFR1 alone had a negative estimate but was not significant (72 patients, p = 0.23). One planned alpha-height test was not estimable because 99.8% of pairs had a beta peak. Limits include one task epoch per patient, 0.5 Hz resolution, noisy peak frequencies, bipolar recordings, epilepsy patients, and RAM sites. The small negative correlations should not be interpreted as physiological anti-coupling; shared aperiodic fitting or band-edge peak detection may contribute. The test does not exclude harmonics in a small subset of pairs.

SEEG · neural oscillations · peak frequency · harmonics · spectral analysis · memory task · epilepsy