Orexin/Hypocretin and Organizing Principles for a Diversity of Wake-Promoting Neurons in the Brain.

Schöne, Cornelia; Burdakov, Denis (2017). Orexin/Hypocretin and Organizing Principles for a Diversity of Wake-Promoting Neurons in the Brain. In: Lawrence, A.; de Lecea, L. (eds.) Behavioral Neuroscience of Orexin/Hypocretin. Current Topics in Behavioral Neurosciences: Vol. 33 (pp. 51-74). Springer 10.1007/7854_2016_45

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An enigmatic feature of behavioural state control is the rich diversity of wake-promoting neural systems. This diversity has been rationalized as 'robustness via redundancy', wherein wakefulness control is not critically dependent on one type of neuron or molecule. Studies of the brain orexin/hypocretin system challenge this view by demonstrating that wakefulness control fails upon loss of this neurotransmitter system. Since orexin neurons signal arousal need, and excite other wake-promoting neurons, their actions illuminate nonredundant principles of arousal control. Here, we suggest such principles by reviewing the orexin system from a collective viewpoint of biology, physics and engineering. Orexin peptides excite other arousal-promoting neurons (noradrenaline, histamine, serotonin, acetylcholine neurons), either by activating mixed-cation conductances or by inhibiting potassium conductances. Ohm's law predicts that these opposite conductance changes will produce opposite effects on sensitivity of neuronal excitability to current inputs, thus enabling orexin to differentially control input-output gain of its target networks. Orexin neurons also produce other transmitters, including glutamate. When orexin cells fire, glutamate-mediated downstream excitation displays temporal decay, but orexin-mediated excitation escalates, as if orexin transmission enabled arousal controllers to compute a time integral of arousal need. Since the anatomical and functional architecture of the orexin system contains negative feedback loops (e.g. orexin ➔ histamine ➔ noradrenaline/serotonin-orexin), such computations may stabilize wakefulness via integral feedback, a basic engineering strategy for set point control in uncertain environments. Such dynamic behavioural control requires several distinct wake-promoting modules, which perform nonredundant transformations of arousal signals and are connected in feedback loops.

Item Type:	Book Section (Book Chapter)
Division/Institute:	04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
UniBE Contributor:	Schöne, Cornelia
Subjects:	600 Technology > 610 Medicine & health
ISSN:	1866-3370
ISBN:	978-3-319-57534-6
Series:	Current Topics in Behavioral Neurosciences
Publisher:	Springer
Language:	English
Submitter:	Stefanie Hetzenecker
Date Deposited:	12 Jul 2018 08:59
Last Modified:	05 Dec 2022 15:13
Publisher DOI:	10.1007/7854_2016_45
PubMed ID:	27830577
Uncontrolled Keywords:	Arousal Brain state Control theory Hypocretin Hypothalamus Neurons Orexin
URI:	https://boris.unibe.ch/id/eprint/116247