Reticular activating system

Brain: Reticular activating system
Deep dissection of brain-stem. Ventral view. (Reticular formation labeled near center.)
NeuroNames	ancil-231

The reticular activating system (or RAS, for Reticular Activating System) is the name given to the part of the brain (the reticular formation and its connections) believed to be the center of arousal and motivation in mammals (including humans).

Functions

The activity of this system is crucial for maintaining the state of consciousness. It is situated at the core of the brain stem between the myelencephalon (medulla oblongata) and mesencephalon (midbrain).

It is involved with the circadian rhythm. Bilateral damage can lead to permanent coma. It is thought to be the area affected by many psychotropic drugs. General anesthetics work through their effect on the reticular formation. Melatonin levels affect RAS.^{[citation needed]}

Fibers from the reticular formation are also vital in controlling respiration, cardiac rhythms, and other essential functions.

Although the functioning of this system is a prerequisite for consciousness to occur, it is generally assumed that this system's role is indirect and it does not, by itself, generate consciousness. Instead, its unique anatomical and physiological characteristics ensure that the thalamocortical system fires in such a way that is compatible with conscious experience. The reticular activating system controls our sexual patterns.

Clinical significance

The reticular activating system (RAS) has received attention from neuroscientists interested in various pathological conditions affecting behaviour, such as Alzheimer's Disease and Autism.^{[citation needed]}.

External links

• Diagram at Stanford University
• Diagram at Rutgers-Camden