Distinguish Between Consciousness and Alertness

Scientists agree about the existence of dramatic global decreases in regional blood flow that occur in non-rapid eye movement (NREM) sleep and about the selective increases that occur in REM sleep (in the amygdala, basal forebrain, parahippocampal cortex, interior cingulate, parietal operculum, and pontine brain stem). Particularly striking is the finding of persistent deactivation of the dorsolateral prefrontal cortex in REM. A natural next step is to investigate the transitions between sleeping and waking. Noting a previously documented difference in the time courses of recovery of wakefulness (instantaneous) and of alertness (delayed), Balkin and colleagues performed PET scans on 27 young adult males at 5 and 20 minutes postawakening. Af…