BCIwiki (bciwiki.com) — Neural activity during motor imagery shifts by task stage, with low-frequency (8-30 Hz) signals predominantly suppressed during preparation and becoming activated during imagery, while high-frequency (60-115 Hz) responses are stronger and more widespread, according to a study using stereoelectroencephalography (sEEG). The research, conducted by scientists at the University of Bath and Huashan Hospital, Fudan University, was published in NeuroImage on May 19, 2026.
The study involved ten epilepsy patients performing cued limb motor imagery while intracranial electrodes recorded activity from cortical and subcortical regions. Low-frequency activity showed suppression during preparation followed by activation during imagery, consistent with ERD/ERS-like dynamics, whereas high-frequency responses were stronger, observed across more regions, and some contacts exhibited activation-suppression sequences. Modulation in deep structures, including hippocampal subfields, suggests that motor imagery engages a distributed network beyond canonical sensorimotor areas. The authors say the findings refine the temporal and spectral characterization of motor imagery and may inform stage-aware BCI feature design and neurorehabilitation.