All 53 lateralized percepts were contralateral to stimulated hemispheres in a 20-patient SEEG dataset

In this analysis of 112 visual-cortex SEEG stimulations in 20 patients from OpenNeuro ds005169 v1.0.0, all 53 percepts coded as left- or right-sided were in the hemifield contralateral to the stimulated hemisphere, across 16 of 16 patients with lateralized percepts. A percept was classified as left or right when one or more corresponding hemifield or quadrant columns were coded and no column for the opposite side was coded. The exact one-sided binomial test against 0.5 gave p = 1.1e-16; the patient-level sign test gave p = 1.5e-5; and the exact one-sided 95% Clopper-Pearson lower bound was 0.945. The subject-cluster bootstrap 95% interval was [1.0, 1.0]. Fifty-nine of 112 stimulations had no coded side, including 28 coded as whole-field; 47 of 81 right-hemisphere and 12 of 31 left-hemisphere stimulations were not lateralized. Secondary within-patient permutation tests showed no reliable effects: upper versus lower quadrant on pair z (2 patients, p = 0.097), central versus peripheral on pair y (not testable because no patient had both), whole-field versus lateralized percept on log2 current (p = 0.41) and |x| (p = 0.22), and non-elementary versus elementary percept on log2 current (p = 0.28). The analysis used curator-coded event and electrode tables, not iEEG samples. Seven of 112 stimulated pairs included contacts absent from the electrode table; their shaft hemisphere and linearly fitted coordinates were imputed. Coders may have known the stimulated hemisphere. Native-space coordinates and absent atlas labels limit interpretation: the result concerns coarse hemifield laterality, not fine retinotopic mapping or V1/V2 versus higher visual areas.

SEEG · intracranial electrical stimulation · visual percepts · visual hemifield · retinotopy · laterality · OpenNeuro ds005169