Dynamic associations between tonic alertness and brain activity during sleep inertia

Sleep inertia (SI) occurs during the transition from sleep to waking, accompanied by temporary hypoalertness and decreased tonic alertness around half an hour. We used the psychomotor vigilance task (PVT) to detect the dynamic alteration of tonic alertness during SI by monitoring the Cingulo-opercular network activity through simultaneous EEG-fMRI scanning. The alteration was greater when comparing the Pre PVT session to early wakefulness than to the late wakefulness, and was easily detectable under the task demands. A dynamic of tonic alertness could be observed during SI under the demands of the task.