Functional Neuroanatomy of the Noradrenergic Locus Coeruleus: Its Roles in the Regulation of Arousal and Autonomic Function Part I: Principles of Functional Organisation

Abstract

The locus coeruleus (LC) is the major noradrenergic nucleus of the brain, giving rise to fibres innervating extensive areas throughout the neuraxis. Recent advances in neuroscience have resulted in the unravelling of the neuronal circuits controlling a number of physiological functions in which the LC plays a central role. Two such functions are the regulation of arousal and autonomic activity, which are inseparably linked largely via the involvement of the LC. The LC is a major wakefulness-promoting nucleus, resulting from dense excitatory projections to the majority of the cerebral cortex, cholinergic neurones of the basal forebrain, cortically-projecting neurones of the thalamus, serotoninergic neurones of the dorsal raphe and cholinergic neurones of the pedunculopontine and laterodorsal tegmental nucleus, and substantial inhibitory projections to sleep-promoting GABAergic neurones of the basal forebrain and ventrolateral preoptic area. Activation of the LC thus results in the enhancement of alertness through the innervation of these varied nuclei. The importance of the LC in controlling autonomic function results from both direct projections to the spinal cord and projections to autonomic nuclei including the dorsal motor nucleus of the vagus, the nucleus ambiguus, the rostroventrolateral medulla, the Edinger-Westphal nucleus, the caudal raphe, the salivatory nuclei, the paraventricular nucleus, and the amygdala. LC activation produces an increase in sympathetic activity and a decrease in parasympathetic activity via these projections. Alterations in LC activity therefore result in complex patterns of neuronal activity throughout the brain, observed as changes in measures of arousal and autonomic function.

A Stress-Related Peptide Bombesin Centrally Induces Frequent Urination through Brain Bombesin Receptor Types 1 and 2 in the Rat

“…The Barrington's nucleus plays a key role in communication between the brain and the bladder (see the review by Valentino et al, 2011). The nucleus neurons that project to the preganglionic parasympathetic column of the lumbosacral spinal cord also project to the locus coeruleus (Valentino et al, 1996;Samuels and Szabadi, 2008), whose neurons have massive collateralized projections that innervate the entire neuraxis, particularly in the forebrain (Swanson and Hartman, 1975). The locus coeruleus initiates and maintains arousal in response to stimuli and modulates the attention process (Berridge and Waterhouse, 2003;Bouret and Sara, 2005).…”

The Irritable Bowel Syndrome: How Stress Can Affect the Amygdala Activity and the Brain-Gut Axis

“…In particular, activation of CRF neurons in the CeA that project to the LC increase its firing thus resulting in a noradrenaline release in the structures it is projecting to (Bouret, et al 2003). LC activation leads to anxiety through the activation of the amygdala and, conversely, anxiety producing stimuli (stressful and fear-inducing stimuli) that increase the activity of the amygdala lead to LC activation (Samuels and Szabadi 2008).…”

Poziom katecholamin w ślinie podczas stresu egzaminacyjnego i wysiłku poznawczego

“…Za generowanie i podtrzymywanie pobudzenia odpowiedzialne są różne układy neurotransmisyjne, przede wszystkim układ noradrenergiczny (Samuels, Szabadi, 2008). Wzrost pobudzenia jest ściśle powiązany ze zwiększeniem częstotliwości wyładowań miejsca sinawego (Aston-Jones, Cohen 2005).…”