BCIwiki (bciwiki.com) — A study published in Journal of Neural Engineering on October 7, 2026, reports that Lee S of the University of Ulsan, Republic of Korea, analyzed two independent public datasets to investigate the timing of regional electroencephalography (EEG) changes during cue-paced motor imagery (MI). The study also examined when information distinguishing movement classes becomes available. Weibo2014 served as the internal dataset and BCI Competition IV dataset 2a as the external dataset.
Both datasets underwent a matched pipeline of causal filtering, ocular regression, and current source density processing. Regional desynchronization onset, when the relevant brain rhythms begin to weaken, was compared under nine combinations of onset definitions and thresholds. Time-resolved decoding tracked class-discriminative information, and its course was modeled both with and without a transition.
Mu and beta desynchronization began in an ordered sequence from occipital cortex through sensorimotor regions and the midline pre-supplementary motor area to lateral prefrontal cortex. This ordering held under all nine onset criteria, channel-count matching, within-trial pairing, and removal of the sensorimotor component. Class-discriminative information rose most steeply 0.60-0.75 seconds after the cue and saturated within a further 0.3 seconds.
In every participant across both datasets, the information transition was closer to sensorimotor desynchronization onset than to cue presentation. It occurred at or after sensorimotor onset in nearly all participants, although the two timings were not shown to be equivalent at the decoding grid's resolution. Windows centered on each region's own onset classified equivalently to reassigned windows. The authors therefore interpret the regional sequence as a temporal landmark for locating useful information, rather than a directly decodable feature.