Short-lived brain state after cued motor imagery in naive subjects

Multi‐channel electroencephalography recordings have shown that a visual cue, indicating right hand, left hand or foot motor imagery, can induce a short‐lived brain state in the order of about 500 ms. In the present study, 10 able‐bodied subjects without any motor imagery experience (naive subjects) were asked to imagine the indicated limb movement for some seconds. Common spatial filtering and linear single‐trial classification was applied to discriminate between two conditions (two brain states: right hand vs. left hand, left hand vs. foot and right hand vs. foot). The corresponding classification accuracies (mean ± SD) were 80.0 ± 10.6%, 83.3 ± 10.2% and 83.6 ± 8.8%, respectively. Inspection of central mu and beta rhythms revealed a short‐lasting somatotopically specific event‐related desynchronization (ERD) in the upper mu and/or beta bands starting ∼300 ms after the cue onset and lasting for less than 1 s.