The assignment discusses the neural basis of alertness and cognitive performance impairments during sleepiness, specifically exploring the effects of 24 hours of sleep deprivation on waking human regional brain activity. The study found that sleep deprivation led to a decrease in global CMRglu by 8%, with significant decreases in absolute regional CMRglu. Subjective and objective alertness declined, while mood remained constant. The results suggest that the deactivation of thalamic regions of the brain after sleep deprivation is associated with attention deficits in cognitive performances.