Electrophysiological studies and sleep-wake cycle

Mammalian sleep and arousal are complex neurobehavioral processes. The advent of devices for recording electrical signals almost a century ago made it possible not only to characterize sleep-wake stages objectively but also to understand the mechanisms underlying these processes. During these years, several tools and combination of approaches that have evolved with technological advances have been used to identify brain regions involved, the cellular and neural substrates in those regions, neurotransmitter phenotypes of the cells involved, and the interactions between sleep-, wake-, and circadian-systems that orchestrate the onset and maintenance of the sleep-waking process under normal and pathological conditions. In this regard, electrophysiology has been a major methodological tool to investigate brain functioning in relation to sleep-wake control. In fact, a significant aspect of our understanding of the neuronal behavior and control of sleep-wake function is based on electrophysiological approaches. This chapter briefly describes the electrophysiological tools/strategies that have been used to understand the sleep-wake regulatory neuronal networks and the mechanisms underlying the sleep-wake cycle.