Ascending reticular activating system (ARAS)

Ascending reticular activating system Overview

The ascending reticular activating system (ARAS) is a network of interconnected nuclei and neuronal circuits located primarily in the brainstem's reticular formation. It projects to the thalamus and cerebral cortex and is essential for regulating wakefulness, attention, arousal, sensation filtering ("sensory gating"), and sleep-wake transitions. The ARAS includes several neurotransmitter-specific nuclei—such as dopaminergic, noradrenergic, serotonergic, histaminergic, cholinergic, and glutamatergic centers—and interacts with structures like the thalamus and hypothalamus. It does not represent a single molecular target but rather a functional neuroanatomical pathway critical for maintaining consciousness; thus it is not considered a therapeutic target in the conventional sense used for receptors or enzymes[1][2][3]. > "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... responsible for regulating wakefulness and sleep-wake transitions." [1] > "Consciousness is an arousal and awareness... achieved through action of the ascending reticular activating system (ARAS) on the brain stem and cerebral cortex." [2] Because it refers to an anatomical/functional network rather than a discrete molecule or receptor protein that can be directly targeted by drugs or measured by biomarkers in isolation—and because "activation" describes its physiological state rather than its identity—this entry should be flagged as incorrect if used as a molecular drug target.

Mechanism of Action

Biological Functions

Safety Considerations