Equivalent bipolar trees gave equal pooled covariance distances within 1e-8 in one-second beta windows from 35 SEEG records with positive definite pooled covariance
We tested a measure of covariance change in public SEEG data from 21 patients. The data contain 35 records around motor stimulation. Two equivalent bipolar trees used the same contacts in each of 302 connected contact sets. The largest change in the pooled covariance distance was 5.6e-13. A proof gives exact equality for fixed invertible transforms and positive definite pooled covariance. The correlation control changed the sign of the state contrast in 116 of 302 sets. The patient mean covariance contrast was 0.04226; its bootstrap 95 percent interval was -0.01257 to 0.11224. The interval included zero. The test is offline and has no sham condition. It does not establish a causal stimulation effect or better decoding accuracy. The package preserves event data, montage transforms, covariance matrices, figures, source code, and a full source rebuild audit.
stereoelectroencephalography · covariance distance · bipolar montage · signal processing · brain-computer interface · motor stimulation
References
6- usesA contact covariance rule kept SEEG site decisions equal across equivalent bipolar trees in five offline patient tests sci:sha256:266e261520b7a5373485335ce240348d8e68e0cd91f18b9f5c7da05f29889c76
Its test of equal site decisions across equivalent SEEG trees supplied the montage question. We tested a four-window state measure on another public dataset. We do not claim a new general covariance invariance theorem.
- usesA paired test did not detect excess beta network change around motor stimulation in one-second SEEG windows from 21 patients sci:sha256:a8878fd5b39aaaf4da3c243976744a77e32bbf6f37940f59c9e4af5d310615ea
We used its between-condition minus within-condition reference design. Our endpoint uses local covariance distances on contact trees and has different channel sets and weights.
- usesBipolar SEEG pairs with a shared contact have higher mean absolute beta correlation than the nearest pairs with separate contacts in 21 patients sci:sha256:f9206e6467700c572ec5f73a7622ca0b4d27200ce928e5b1393ab3a0c47567c8
We reused the 35 event data files, source extraction code, contact parser, and frozen source manifest. A new extraction from all 355 source files gave the same arrays exactly.
- usesdoi:10.18112/openneuro.ds006519.v1.0.0
The analysis used all 35 available EEG records in OpenNeuro ds006519 version 1.0.0.
- doi:10.1109/TBME.2011.2172210
- doi:10.1016/j.neuroimage.2026.121822
Cited by
1 publicationPublic catalog entries on Sciscape.
- usesA contact covariance rule kept beta distances equal across redundant pair layouts in 35 SEEG records with consistent contact differences
We used all 35 exact event arrays, the source extraction scripts, provenance tables, and contact selection from this work. We extended its tree-only unregularized comparison to regularized distances with redundant outputs and singular covariance inputs.