Functional-MRI correlates of cued slow-eye-closure and task non-responsiveness during visuomotor tracking.

Slow-eye-closure and task non-responsiveness are important behavioural markers of microsleeps. This paper presents preliminary results on the neural correlates of voluntary slow-eye-closure and voluntary non-responsiveness during performance of a continuous visuomotor tracking task. Functional-MRI (fMRI), EEG, eye video, and tracking responses were recorded from 5 normal subjects while they performed a continuous visuomotor tracking task inside an MRI scanner for 10 min. During this time, they were cued to simultaneously stop tracking and slowly close their eyes or stop tracking without eye-closure several times. Analysis of fMRI data revealed several regions involved in cued slow-eye-closure and cued task non-responsiveness, including occipito-parietal visual regions, midline default mode regions, and fronto-parietal attention regions. These results will be of considerable value in the interpretation of changes in BOLD activation and EEG activity associated with behavioural microsleeps.