Sleep-deprived rats suggest sleep is not necessarily a whole-brain phenomenon.
This rat is not as alert as it looks.Yuval Nir
The closed eyes, the unresponsiveness, the drool — sleep is an easily recognizable, all-encompassing state. But the divide between sleep and wakefulness may not be as clearcut as we thought.
Research published today in Nature demonstrates that in visibly awake rats, neurons in some areas of the brain's cortex briefly go 'offline'. In these pockets, neuronal patterns resemble those associated with non-rapid eye movement (NREM) sleep1.
"The rats were awake, but awake with a nice sprinkling of localized sleep in the cortex," says Guilio Tononi, a neuroscientist at the University of Wisconsin–Madison and lead author of the study.