Eight versus four letters showed no clear left advantage in late hippocampal theta in 11 patients under the stored SEEG reference

We tested whether eight versus four letters changed late hippocampal theta power more on the left than on the right. We used OpenNeuro ds004752 version 1.0.1. Source anatomy gave matched parts on both sides in 11 patients. The primary analysis used 51 sessions, 78 selected contacts, and 2,123 trials after correct prior responses. Theta was 4 to 8 Hz. The window was seconds 4 to 6 of each stored trial. We used the stored SEEG reference. Each patient had equal group weight. The mean left minus right load effect was 0.150 dB. The 95 percent patient bootstrap interval was -0.498 to 0.697 dB. The exact two-sided sign-flip probability was 0.643. This result gives no clear evidence of a left advantage. It does not establish equal side effects. Nine fixed secondary analyses were also uncertain. Fresh raw data from all 11 patients matched the saved power features. The package preserves code, features, raw examples, source versions, hashes, and an offline repeat check. This is a new secondary analysis of an existing epilepsy cohort. It is not an independent replication.

hippocampus · theta power · verbal working memory · SEEG · memory load · hemispheric asymmetry