CCEP responses decreased with distance at five stimulation sites in one SEEG patient, while far-response rates varied

We examined whether cortical stimulation pulse trains and stimulated pairs could be recovered from the signal in one patient (sub-112) from OpenNeuro ds006254 v1.0.0, which has no event markers. Seven windows on a fixed time grid were sampled from one 13.7 GB EDF recording; five contained valid 1 Hz trains (14–30 pulses) and adjacent stimulated contacts. For each site, we measured responses in 182 bipolar pairs and defined responsiveness as a maximum absolute z score greater than 6 in 15–300 ms. Response size decreased with distance at all five sites (Spearman rho −0.20 to −0.58; permutation p ≤ 0.005). The responsive fraction below 15 mm was 0.63–1.00. Beyond 50 mm it ranged from 0.02 to 0.51 across sites. At two sites, far responses were repeatable in split halves (median r = 0.92 and 0.85; median peaks at 123 and 88 ms). This result is limited to one patient, five sites selected by a fixed time grid, and 14–30 pulses per site. Pulse count was not equalised, the z threshold depends on noise, bipolar recordings can contain far-field signals, and stimulation sites were inferred from artifacts rather than logs. The four seizure-inducing sites in this patient were not sampled. Coordinates were not checked against anatomy.

cortico-cortical evoked potentials · stereo-EEG · electrical stimulation · neural response · distance · OpenNeuro