To accurately capture and address the multi-dimensional feature variations in cross-subject motor imagery electroencephalogram (MI-EEG), this paper proposes a time-frequency transform and Riemannian manifold based domain adaptation network (TFRMDANet) in a high-dimensional brain source space. Source imaging technology was employed to reconstruct neural electrical activity and compute regional cortical dipoles, and the multi-subband time-frequency feature data were constructed via wavelet transform. The two-stage multi-branch time–frequency–spatial feature extractor with squeeze-and-excitation (SE) modules was designed to extract local features and cross-scale global features from each subband, and the channel attention and multi-scale feature fusion were introduced simultaneously for feature enhancement. A Riemannian manifold embedding-based structural feature extractor was used to capture high-order discriminative features, while adversarial training promoted domain-invariant feature learning. Experiments on public BCI Competition IV dataset 2a and High-Gamma dataset showed that TFRMDANet achieved classification accuracies of 77.82% and 90.47%, with Kappa values of 0.704 and 0.826, and F1-scores of 0.780 and 0.905, respectively. The results demonstrate that cortical dipoles provide accurate time–frequency representations of MI features, and the unique multi-branch architecture along with its strong time–frequency–spatial–structural feature extraction capability enables effective domain adaptation enhancement in brain source space.
For patients with MRI-negative drug-resistant epilepsy, noninvasive localization of targets for transcranial electrical stimulation (tES) remains a clinical challenge. This study proposes a novel target localization approach that integrates electroencephalogram source imaging, brain network analysis, and a neural computational model. We analyzed electrocorticography (ECoG) data from 12 patients, quantified the epileptogenicity of epileptic network nodes, and noninvasively located optimal stimulation targets. Three source imaging methods and two brain network reconstruction measures were compared for localization performance. Among four patients with good outcomes, the method accurately localized epileptogenic tissues in three. Results of tES simulation demonstrated that cathodal direct current stimulation of the target region significantly reduced the brain network's epileptogenicity. This study provides a noninvasive, quantifiable targeting strategy for tES therapy in epilepsy patients.