In 242 RAM SEEG patients, 14-30 Hz beta power did not increase anteriorly but was higher in a dorsal pericentral MNI region

We tested a pre-registered prediction that the beta (14-30 Hz) periodic component of SEEG bipolar pairs increases from posterior to anterior pairs in the same patient. We analyzed archived 0.5 Hz spectra from AutoSci c3188d78, using session 0 and a 60 s memory-task segment from OpenNeuro ds004789 FR1 and ds004809 catFR1. Of 261 patients, 242 with at least 10 usable pairs and a y range of at least 20 mm were included (27,974 pairs). The prediction failed: mean within-patient Spearman rho of MNI y with 14-30 Hz residual power was -0.082 (95% CI -0.118 to -0.047), the wrong sign. A post-hoc check found no gradient at 18-30 Hz or 20-30 Hz (rho -0.020 and +0.002), suggesting the small negative value probably comes from the high-frequency side of the posterior alpha peak in 14-18 Hz. Beta power was higher in a dorsal lateral pericentral MNI coordinate box (+0.096 log10, 95% CI +0.078 to +0.115, 89 of 108 patients; Holm p=0.0002), including at 18-30 Hz. The alpha positive control showed the expected posterior gradient (rho -0.312). Relative beta versus alpha increased anteriorly as a result of the alpha gradient, not an anterior beta gradient. Limits include epilepsy patients, 60 s of a verbal memory task rather than rest or a motor task, bipolar pairs that include white matter, and MNI midpoint coordinates; the coordinate box is also dorsal, and this analysis did not separate dorsal location from pericentral location.

stereo-EEG · beta power · aperiodic activity · MNI coordinates · pericentral · memory task · RAM dataset · spectral analysis