Sleep, Dreams, and States of Consciousness
Introduction and Organization of SleepWakefulness
Understanding the brain basis of consciousness is one of the oldest dreams of neuroscientists and physicians. Although knowledge of its subtleties is at a very early stage, we are now beginning to understand some of the basic mechanisms controlling the changes of consciousness associated with sleep and wakefulness.
The Electroencephalogram Is an Important, Although Limited, Tool for the Study of States of Consciousness
We begin with a brief review of the biological basis of the electroencephalogram (EEG) and evoked potentials (EPs). When activity is synchronous, neurons in the cerebral cortex generate electrical signals strong enough to be detected through the skull by sensors (electrodes) placed on the scalp. These small (microvolt) electrical signals are amplified and filtered to produce EEG recordings. Although the EEG is a crude way to determine brain activity (similar to figuring out what is happening in a football game by putting...
KeywordsSleep Deprivation Basal Forebrain Reticular Formation Extracellular Adenosine Delta Wave
This work was supported by awards from the Department of Veterans Affairs, Medical Research Service and NIMH (R37 MH39,683, R01 MH62522, and R01 MH40,799). Portions of this chapter are adapted from McCarley RW et al. Brain stem neuromodulation and REM sleep. Sem. Neurosci. 1995;7:341–354; McCarley RW. Neurophysiology of sleep: Basic mechanisms underlying control of wakefulness and sleep. In: Chokroverty S, ed. Sleep Disorders Medicine, 2nd edition. Boston: Butterworth-Heinemann, 1999, pp. 21–50; McCarley RW. Human electrophysiology: cellular mechanisms and control of wakefulness and sleep. In: Yudofsky S and Hales RE, eds. Handbook of Neuropsychiatry, Fourth edition. New York: American Psychiatric Press, 2001; Steriade M and McCarley RW, Brain Control of Wakefulness and Sleep. New York: Kluwer Academic/Plenum, 2005; McCarley RW. Neurobiology of REM and NREM sleep. Sleep Med. 2007;8(4):302–330.