In the news focus story "Simple sleepers" (18 July, p. 334), E. Youngsteadt highlights recent advances, derived from genetic research in fruit flies and other "simple" animal models, in our understanding of sleep. The power of this genetic approach is undeniable, but the simplicity that renders such model animals amenable to genetic manipulation necessarily limits their ability to model all aspects of sleep in mammals. Most notably, simple animal models lack the changes in brain activity that define mammalian slow-wave sleep (SWS) and rapid eye movement (REM) sleep (1). Until we determine the functional relevance of the changes in brain activity that define these characteristics of mammalian sleep, our understanding of human sleep may be incomplete. We contend that birds, as the only non-mammalian taxonomic group to exhibit SWS and REM sleep, provide a largely untapped opportunity to determine the functions of these states in mammals. Reptiles and amphibians lack comparable sleep states, indicating that SWS and REM sleep evolved independently in the respective ancestors of mammals and birds (2).
展开▼
