Invited Symposium: Role of the Basal Forebrain Neurons in Cortical Activation and Behavioural State Regulation
Extracellular recordings of unit activity within cholinergic regions of the magnocellular basal forebrain (mBF) in freely-moving animals reveal several cell types. Activity of at least two cell types is strongly modulated by the sleep-wake cycle. One type displays elevated discharge during waking movements, reduced mean discharge during nonREM sleep and elevated discharge during phasic events of REM sleep. In cats, a subset of these cells can be identified as cortically-projecting by antidromic activation in response to cortical stimulation, and can be hypothesized to be cholinergic. Neurons with similar sleep-wake discharge profiles can be recorded in the mBF of rats. Another mBF cell type displays elevated discharge during sleep, with minimum activity during waking. In cats, these cells are located within the mBF, ventral to cholinergic neurons. In rats, sleep-active cells are scattered throughout the ventral mBF, and are concentrated more medially in the ventrolateral preoptic area. Sleep-active cells can be hypothesized to modulate the excitability of mBF cholinergic neurons. Some evidence suggests that sleep-active cells are GABAergic. Experiments in rats using local perfusion of GABAergic agonists and antagonists combined with single unit recording, indicate that increased GABA-mediated inhibition contributes to diminished discharge of putative mBF cholinergic neurons during nonREM sleep.
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|Szymusiak, R; (1998). Sleep-Waking Discharge Patterns of Basal Forebrain Neurons in Rats and Cats. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium. Available at URL http://www.mcmaster.ca/inabis98/semba/szymusiak0400/index.html|
|© 1998 Author(s) Hold Copyright|