Mean beta power decreased after stimulation and matched periods with no marked pulses in 113 hippocampal SEEG records from seven people

We tested beta power from 13 to 30 Hz in public hippocampal depth records from an implanted stimulator. The fixed source sample had 222 records from seven people. Of these, 197 records had enough time for a five-second measurement that started five seconds after the last marked pulse ended. We chose earlier periods without marked stimulation. Each control had the same measurement gap and similar pre-window beta power and absolute voltage change. Only 113 records met the planned match limit of one candidate standard deviation on each feature. Each person had equal weight. Mean beta power changed by -1.08 dB after stimulation and -1.41 dB after the matched control periods. The contrast was +0.34 dB, with a person bootstrap 95 percent interval from -0.29 to +1.15 dB. A beta decrease alone did not identify a stimulation response in this sample. Earlier controls were not random sham trials, and two people had only one and three matched records. The result does not establish or rule out a causal stimulation effect. The package contains raw data, source hashes and object versions, the local plan, control features, analysis code, three figures, and reproduction instructions. A separate reader agreed on all 8.1 million voltage samples. A separate run reproduced all six numerical result files exactly.

SEEG · hippocampus · beta power · brain stimulation · matched controls · signal change · intracranial EEG