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Ascending reticular activating system. Reticular formation labeled near center. The ascending reticular activating system (ARAS), also known as the extrathalamic control modulatory system or simply the reticular activating system (RAS), is a set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and ...
It is a part of the reticular activating system. The locus coeruleus, which in Latin means "blue spot", is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the norepinephrine it produces are described collectively as the locus coeruleus-noradrenergic system or LC ...
The pedunculopontine nucleus ( PPN) or pedunculopontine tegmental nucleus ( PPT or PPTg) is a collection of neurons located in the upper pons in the brainstem. [1] [2] It is involved in voluntary movements, [3] arousal, and provides sensory feedback to the cerebral cortex and one of the main components of the reticular activating system.
Arousal is the physiological and psychological state of being awoken or of sense organs stimulated to a point of perception. It involves activation of the ascending reticular activating system (ARAS) in the brain, which mediates wakefulness, the autonomic nervous system, and the endocrine system, leading to increased heart rate and blood pressure and a condition of sensory alertness, desire ...
Ascending reticular activating system. The ascending reticular activating system consists of a set of neural subsystems that project from various thalamic nuclei and a number of dopaminergic, noradrenergic, serotonergic, histaminergic, cholinergic, and glutamatergic brain nuclei.
The activation-synthesis hypothesis, proposed by Harvard University psychiatrists John Allan Hobson and Robert McCarley, is a neurobiological theory of dreams first published in the American Journal of Psychiatry in December 1977. The differences in neuronal activity of the brainstem during waking and REM sleep were observed, and the hypothesis ...
One such example is the heterogeneous collection of more than two dozen nuclei on each side of the upper brainstem (pons, midbrain and in the posterior hypothalamus), collectively referred to as the reticular activating system (RAS). Their axons project widely throughout the brain.
Function and location. The parafacial zone promotes slow-wave sleep by inhibiting the glutamatergic parabrachial nucleus (a component of the ascending reticular activating system that mediates wakefulness and arousal) via the release of the inhibitory neurotransmitter GABA onto those neurons.