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Reticular activating system (also known as RAS) is a part of the brain, responsible for the many important brain functions. Mammals are the only animals that have this system and the scientists believe that RAS is the main reason for possessing cognitive functions.

Where is RAS

RAS connects two regions of the brain, upper and lower brain. It is a connection between the brain stem, which controls reflexes and involuntary functions and cerebral cortex (part of the brain that regulates thinking and consciousness). Reticular activating system is consisted of: dorsal hypothalamus, thalamic intralaminar nucleus, tegmentum, reticular formation and mesencephalon. There is also a definition that divides RAS to ascending and descending RAS. Ascending reticular activating system is connected to thalamus, hypothalamus and cerebral cortex, while descending RAS is linked to sensory nerves and cerebellum.

What Does RAS Do

This brain system functions are controlled by neurotransmitters, both cholinergic and adrenergic. As the most important role of RAS scientists and doctors recognize is the transit from sleeping to being fully and totally awake. RAS works in the different direction, too, regulating the beginning of sleeping. Dreaming is also a process that involves RAS, and this system must be fully functional in order to dream anything. RAS filters the information we have about the outside world, enabling us to focus on some specific tasks, such as certain thoughts, facts and details. It is also responsible for the response of the body to the external stimuli. How will our cardiovascular or respiratory system react to some stimulus mainly depends on RAS. Our sexual functions and eating lifestyle depend on this system as well. Walking, especially coordination of our body while we are walking is also controlled by RAS.

What if It Gets Damaged

As it’s located on the specific, back part of the brain, RAS is very exposed and can be easily damaged. It is the part of the brain most easily affected by many different types of accidents. If the reticular activating system got damaged, the person might get into comatose state. Some medications might also affect this part of the brain. Psychotropic drugs and anesthetic medications are known to influence RAS and cause semi-consciousness or even unconsciousness. Problems in reticular activating system are linked to some serious disorders and diseases. Sleeping problems and narcolepsy can be caused by some RAS disorders. Attention deficit disorders are also associated with RAS problems. Some researchers found out that Alzheimer’s disease patients may also suffer from some type of reticular activating system disorders.

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