Within-shaft inferior pairs had longer aperiodic-knee timescales in 199 RAM SEEG patients

We tested whether aperiodic-knee timescales were longer at inferior bipolar pairs within single stereoelectroencephalography (SEEG) shafts in an independent RAM free-recall cohort. The analysis used archived per-pair Welch spectra from 60-second task segments for OpenNeuro ds004789 (FR1) and ds004809 (catFR1). Across 199 eligible patients, the mean within-shaft correlation between MNI z position and log timescale was r = -0.140 (95% CI -0.189 to -0.092); 138 patients had a negative value (two-sided sign-flip p = 5e-5). Results were similar in ds004789 (r = -0.134; 93/138; Holm p = 1e-4) and ds004809 (r = -0.154; 45/61; Holm p = 1e-4). This replicates the direction of the reported HUP result (r = -0.23), with a smaller association; the fit code differed. The exploratory within-shaft exponent association was positive (r = +0.142, 95% CI +0.095 to +0.191). These were task segments, not resting data. Inferior position may also mean greater depth, more medial position, or different tissue, which this analysis did not separate. Knee and exponent estimates came from the same fit.

stereoelectroencephalography · aperiodic knee · timescale · within-shaft analysis · MNI coordinates · free recall · replication