An arXiv preprint presents STEAM, a hierarchical transfer framework for EEG decoding that reconciles general-purpose representation learning with paradigm-specific specialization in EEG foundation models, using a dual-branch spatio-temporal encoder with a shared soft mixture-of-experts (SSMoE) module that aligns the spatial and temporal branches.
The researchers report that across 7 downstream datasets and 14 evaluation settings, STEAM attained the best average rank among the compared methods at a competitive inference cost, and its hierarchical pre-training strategy further specializes the model to a target paradigm without retraining from scratch, yielding consistent gains in decoding accuracy. This study is a preprint and has not been peer reviewed.