Reticular Activating System

The reticular activating system (RAS) is one of the most important parts of the brain, which controls many vital brain functions of consciousness. This article is a short introduction to reticular activating system functions and the way it influences human behavior.

Every one of the conscious functions that our mind is capable of, can be traced back or mapped to some part of the brain, which is probably one of the most complex organizations of matter in the universe! The mind as an entity is created by the brain and every process of the mind has an origin in some brain mechanism. This article talks about reticular activating system, which is one of the most significant and vital parts of the human brain that affects cognition.

Research in neuroscience has revealed, that a certain part of the brain called the reticular activating system is responsible for many cognitive functions related to awareness. This was revealed through study of mammalian brains, in which this area is an exclusive feature. Let us explore the location, structure and functions that are attributed to this area of the brain.

Reticular Activating System: Location & Structure

The reticular activating system connects the lower parts of the brain, which is the brain stem, to the cerebral cortex through various neural paths. The brain stem controls most of the involuntary functions as well as reflexes of the body, while cerebral cortex is the seat of consciousness and thinking abilities. So, the reticular activating system forms a link between these two different regions. It is a bridge between the upper brain and the lower brain.

Studies have revealed that there are two most important parts of the reticular activating system (RAS). One is the ascending reticular activating system (which has connections with the cerebral cortex, hypothalamus and thalamus) and the other is the descending reticular activating system (which is connected to the cerebellum and many sensory nerves). A large part of the reticular activating system consists of the brain parts that are responsible for the survival instincts. Hence, it has a deep connection with awareness functions of the brain. The main parts which constitute the RAS are:

• Reticular Formation in the Midbrain
• Mesencephalon
• Dorsal Hypothalamus
• Thalamic Intralaminar Nucleus
• Tegmentum

The RAS functions are controlled by certain cholinergic (related to acetylcholine) and adrenergic (related to Adrenaline) neurotransmitters.

Reticular Activating System Functions Now let us see what are the various functions of the reticular activating system and how are they important for human cognition and survival. One of the major functions of the RAS is the regulation of transition between sleep and wakefulness. The transition that we make from deep sleep to being fully awake and functional, as well as the reverse function, is controlled by the RAS. This system also plays a role in the during REM sleep when we experience dreams

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The reticular activating system is responsible for providing an integrated (cardiovascular, respiratory and motor) response to external stimuli. The ability to filter out information from external sources and focus on one particular fact, detail or thought is controlled by the RAS. It also controls coordination during walking, sexual functions and eating habits.

Reticular activating system damage can lead to a transition into coma. Because of its positioning at the back of the brain, this brain area is very vulnerable to damage during accidents. Brain researchers have linked disorders in the RAS to attention deficit disorders, Alzheimer’s disease, narcolepsy and sleep disorders. Anesthetics and psychotropic drugs directly affect the reticular activating system, causing a transition into unconsciousness or semi-consciousness. Reticular activating system and goals we set have a relation, as it controls the ability to focus and sift through incoming information.

Read more on:

• Brain Parts and Functions
• Human Brain Diagram
• Right Brain Vs Left Brain
• Suprachiasmatic Nucleus

So, this was an overview of the reticular activating system and its functions. It is simply amazing to explore the working of the human brain. So, now you know who is responsible when you don’t wake up on time or you are not paying attention! It is the reticular activating system of course!