Activation of cortical interneurons during sleep: an anatomical link to homeostatic sleep regulation?

• Published in: Trends in neurosciences (Regular ed.) 2011-01, Vol.34 (1), p.10-19
• Main Authors: Kilduff, Thomas S, Cauli, Bruno, Gerashchenko, Dmitry
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Brain; Cerebral Cortex - cytology; Cerebral Cortex - physiology; Electroencephalography; Enzymes; Fundamental and applied biological sciences. Psychology; gamma-Aminobutyric Acid - metabolism; Homeostasis; Humans; Interneurons - cytology; Interneurons - physiology; Medical sciences; Nervous system involvement in other diseases. Miscellaneous; Neurobiology; Neurology; Neurons; Nitric oxide; Nitric Oxide - metabolism; Nitric Oxide Synthase Type I - metabolism; Sleep; Sleep - physiology; Sleep. Vigilance; Vertebrates: nervous system and sense organs
• ISSN: 0166-2236; 1878-108X
• DOI: 10.1016/j.tins.2010.09.005

Although slow wave activity in the EEG has been linked to homeostatic sleep regulation, the neurobiological substrate of sleep homeostasis is not well understood. Whereas cortical neurons typically exhibit reduced discharge rates during slow wave sleep (SWS), a subpopulation of GABAergic interneurons, which express the enzyme neuronal nitric oxide synthase (nNOS), has recently been found to be activated during SWS. The extent of activation of these nNOS neurons is proportional to homeostatic sleep ‘drive’. These cells are an exception among cortical interneurons in that they are projection neurons. We propose that cortical nNOS neurons are positioned to influence neuronal activity across widespread brain areas. They could thus provide a long-sought anatomical link for understanding homeostatic sleep regulation.