Toward a cognitive neuroscience of sleep.

Abstract

sleep is the only one whose basic biological function all of these questions, “how” can refer to the nature was not clear two thousand years ago. Yet, as we of the changes, the brain mechanisms underlying enter the 21st century, researchers are still arguing the changes, or the evolutionary pressures that led over the functions of both sleep and dreams. There to the changes. This is a tall order, and most work appear to be two reasons for this continued unto date has focused on the first of these, the certainty. First, the sleep research community has description of the changes themselves. been slow to accept that sleep serves many basically Three of the articles in this issue attempt to unrelated systems, including, for example, endissect the actual cognitive dysfunctions caused by docrine, immunologic, and thermoregulatory, as disturbed sleep, both in children [4] and in adults well as cognitive, functions [1–3]. But the second [5, 6]. Given that the cognitive impairment resulting reason is the complexity of the relationships befrom sleep deprivation plays such a major role in tween sleep and cognition. While it is obvious to both highway fatalities and industrial accidents [7], anyone who has skipped a night of sleep that cogit is not surprising that so much research has nitive functioning deteriorates with sleep depgone into understanding this very real public health rivation, characterizing the precise deficits has been problem. The extent of the problem is impressive. remarkably difficult. Largely this is a consequence Blunden et al., for example, cite studies [8, 9] of our basic ignorance of cognitive functioning in indicating that the community prevalence rate for general. So it has only been with the development of excessive daytime sleepiness in children is in the the cognitive neurosciences that sleep researchers range of 36–42%. have been given the tools they need to even define The consequences are equally impressive. Blunthis exciting and important question. The articles den et al. [4] report in this issue that sleep related in this issue of Sleep Medicine Reviews provide a obstructive breathing disorders in children are assuperb review of much of the work currently being sociated with significant attentional and memory done in this field. deficits, as well as a more general impairment in There are several ways to study the links between school performance and an increase in problematic sleep and cognition. We can ask how cognition is behaviors. In a second article, Fulda and Schulz [6] altered during sleep or as a consequence of sleep. report on cognitive performance in adults with We can ask how cognition is altered by changes in various sleep disorders. Overall, they found poorer