Chronobiology and Sleep Disorders

In this section on chronobiology and sleep disorders, the seven chapters describe considerable advances in this field since the Fourth Generation of Progress was published. This group of chapters seeks to integrate our basic and clinical knowledge and to convey the high level of current excitement in sleep and biological rhythm research. All these chapters present certain cross-cutting themes providing a basic and clinical integration of both primary sleep disorders and those disorders in which sleep alterations represent important aspects of serious neuropsychiatric disorders. In Chapter 128, on basic mechanisms, Pace-Schott and Hobson add a wealth of new detail to our knowledge of the brain structures involved in the control of sleep and waking, as well as the cellular level mechanisms that orchestrate the sleep cycle by neuromodulation. This chapter focuses on the brainstem neuromodulatory systems and the more specific organization of those systems in controlling the alternation of wake, non–rapid eye movement (NREM) sleep, and REM sleep. Interactions of diverse neuromodulatory systems operate in widespread subcortical areas to amplify or suppress REM sleep generation, as well as to facilitate onset and offset of the control of behavioral state by the pontine REM-NREM oscillator. This existence of an executive aminergic-cholinergic reciprocal interaction system controlling REM-NREM alternation in the pontine brainstem has been strongly confirmed by recent findings. In Chapter 129, Lewy discusses circadian phase sleep and mood disorders and covers the following areas: circadian anatomy and physiology; the shifting of circadian phase using bright light; an update on seasonal affective disorders; discussion of other circadian phase disorders such as shift work and jet lag; and, finally, a section on melatonin and