Monday, December 18, 2006
Sleep deprivation slows the generation of new nerve cells
An interesting finding from Mirescu et al.... It is known that prolonged sleep deprivation is stressful, has adverse effects on cognitive performance and health, and raises corticosterone levels. Their work looks at new nerve cell formation (neurogenesis) in the rat hippocampus, which is central to cognitive performance. They show "that sleep deprivation inhibits adult neurogenesis at a time when circulating levels of corticosterone are elevated. Moreover, clamping levels of this hormone prevents the sleep deprivation-induced reduction of cell proliferation. The recovery of normal levels of adult neurogenesis after chronic sleep deprivation occurs over a 2-wk period and involves a temporary increase in new neuron formation. This compensatory increase is dissociated from glucocorticoid levels as well as from the restoration of normal sleep patterns. Collectively, these findings suggest that, although sleep deprivation inhibits adult neurogenesis by acting as a stressor, its compensatory aftereffects involve glucocorticoid-independent factors."