Microsleeps: Some brain regions nap during wakefulness
Microsleeps usually refer to ultra-brief naps which compromise all behaviour. This paper finds that parts of the brain that can go to sleep whilst the person as a whole remains awake. This may account for those absent-minded lapses? (Dolphins though and some other aquatic species do it more sensibly, they shut half-their brain down while the other half sleeps!)
Vladyslav V. Vyazovskiy, Umberto Olcese, Erin C. Hanlon, Yuval Nir, Chiara Cirelli, Giulio Tononi. Local sleep in awake rats. Nature, 2011; 472 (7344): 443 DOI: 10.1038/nature10009
