The reticular formation is a powerful filter for all the data from sounds, tastes, and images around us, allowing you to focus on important information. This system’s primary function is to alert the higher brain centers to critical information while filtering unnecessary incoming signals. Destruction and severe damage to this formation can lead to profound coma and a vegetative state.
The reticular formation originates from the vertebrobasilar system or the posterior circulation in the brain and doesn’t contain any distinct boundaries. In addition, it serves as an integration and relay center for the vital brain system responsible for various functions essential for survival.
Below we present more details on reticular formation, the disorders linked to the systems, and the critical involvement in processes like awareness and consciousness.
The Structure Of The Reticular Formation
The Reticular Formation is a net-like structure consisting of various brainstem nuclei and neurons covering a spread-out portion of the brainstem. The formation starts in the mesencephalon and extends into the medulla. Furthermore, it extends into the oblongata and connects to the superior cervical spinal cord segment. The reticular formation consists of over 100 neural networks connecting and coordinating with various systems.
The Median Column
The reticular formation’s median column originates from the brainstem’s center line. It extends from the medulla up to the midbrain. In addition, it is present in the para median zone of the brain. This column consists of nuclei made up of intermediate-sized neurons. The nuclei of the median column are collectively known as the nuclei of Raphe.
This adjacent column in the mid-line of the brain contains the dorsal raphe nucleus, nucleus raphe magnus, and neurons responsible for producing the neurotransmitter serotonin. Serotonin is a chemical responsible for transmitting information between nerve cells in the brain and systems throughout the entire body.
The Medial Column
The medial column of the reticular formation originates in the lower pons and extends to the medulla. Furthermore, it projects to the midbrain nucleus, and the connections are responsible for controlling eye movements, brainstem reflexes, and swallowing. This column consists of nuclei made up of large-sized neurons. This column is also known as the magnocellular column.
This column contains the pontine tegmental reticular nucleus, the cuneiform and sub cuneiform nuclei, and a grouping of large cell bodies known as the nucleus reticularis gigantocellularis.
The Lateral Column
The lateral column originates in the medulla and extends to the lower pons of the brainstem. Furthermore, it projects to the spinal cord to control muscle tone, respiration systems, and arterial pressure. This column consists of nuclei made up of small neurons. This column is also known as the parvo-cellular column.
Ascending Afferent Connections
The ascending tracts of the reticular formation make up the reticular activation system. This system receives input directly or indirectly from various sensory sources. Then through the thalamic nuclei, it activates the cerebral cortex and heightens arousal. The nuclei of the reticular formation that are responsible for modulating the activity of the cerebral cortex form part of the ascending reticular activating system.
The reticular formation receives information from the connections to the cerebral cortex, globus pallidus, hypothalamus, limbic formation, deep cerebellar nuclei, olfactory input, and the brain stem.
Descending Efferent Connections
The Descending Tracts originate from the medullary and pontine reticular formation. These are mainly responsible for influencing muscle tone and posture. In addition, these cell bodies contribute to descending fibers connecting to the lateral reticulospinal tract.
The reticular formation projects information by connecting to the spinal cords, motor region, limbic forebrain areas, hypothalamus septum, cerebellum, various brainstems, spinal autonomic regions, spinal cord sensory regions, and thalamus.
Functions Of The Reticular Formation
The reticular formation consists of a network of tracts and interconnected structures that functions as an integrated relay and coordination center. These networks are responsible for many vital life functions and protected reflexes, including the following:
Modulation Of Pain
The reticular formation is one of the pathways responsible for transporting pain signals from the lower body to the cerebral cortex. In addition, the pathways that originate in the Reticular Formation are accountable for blocking specific pain signals to the brain, activating the endogenous opioid system. Furthermore, the pain signals that reach the Reticular Formation significantly impact cardiovascular and motor control during the “fight or flight” reaction.
Monitor Ocular Response
The reticular formation and its systems play a vital role in head movement, coordination of eye saccades, and eye gaze. The mesencephalic reticular formation is responsible for coordinating vertical gaze. Whereas the paramedian pontine reticular formation for horizontal gaze. Furthermore, the medullary pontine reticular formation is accountable for coordinating gaze holding and head movements.
In addition, these formations connect utilizing the descending reticulospinal neurons to coordinate neck movements and posture with eye movement. Furthermore, they directly attach to the extraocular motor nuclei and are vital for saccadic eye movement.
REM Sleep And Consciousness
The reticular formation extends to the thalamus and cerebral cortex, partially giving it control of what comes to our conscious attention by filtering sensory signals that reach the cerebrum. In addition, the signals responsible for generating characteristics associated with REM sleep originate from the Reticular Formation and transmit to the superior colliculi’s motor layers.
Sleep-Wake Transition Cycle
The complex bundle of nerves that form part of the reticular formation is responsible for regulating wakefulness and sleep-wake transition. In addition, it functions to filter out interfering noise and information while you are sleeping. Furthermore, it slows your brain’s processing functions of signals and messages during sleep. The reticular formation achieves this by changing the brain’s electrical activity.
Learning Through Focus
The reticular formation helps with learning and aids in learning new words. In addition, the structures allowing learning are responsible for identifying common phrases and words, like hearing your name in a crowded room. Furthermore, it improves learning ability by helping to stay focused. Finally, it helps you recall vague details and memories you concentrate on by actively filtering them to your brain and piecing them together.
Various Muscle Activities
The reticular formation coordinates the activity of the respiratory centers responsible for the muscles that control respiration. In addition, it works alongside the vestibular apparatus to preserve the muscle tone of the antigravity muscles that aid in the process of standing. Furthermore, it affects the muscles that control facial expressions and symmetrical facial responses like smiling.
Filtering Process For Habituation
The reticular formation is responsible for the function that teaches the brain to ignore meaningless, repetitive stimuli while remaining sensitive to others.
Safety And Awareness
The reticular formation filters information filters through various information received from sensory inputs, nervous systems, and connected systems. It uses this information to alert you when a specific scenario or action poses a threat to you. This system is responsible for triggering your body’s “fight-or-flight response.”
Aid In Respiration Functions
The respiration process involves using the diaphragm, intercostal muscles, and accessory muscles. The reticular formation controls the accessory muscles and primary muscle functions that include moving the head, neck, chest, and back.
Various Visceral Function
The reticular formation is responsible for the visceral function like salivation, vomiting, gastric secretion, heart rate, and blood pressure through autonomic nervous systems located in the medulla.
Arousal Of Senses
The reticular formation is most commonly known for influencing behavioral arousal. In addition, the reticular formation is responsible for causing arousal in all senses except for smell in response to certain emotions and muscular movements. Furthermore, it filters information from the anterolateral system that processes pain, light touch, and temperature.
Improve Attention Span
The reticular formation filters unimportant information and signals that allow you to focus more on the important ones and stay focused for a more extended period.
Psychological Function Of The Reticular Formation
There are numerous references to the reticular formation in psychology and motivational courses. You have all heard phrases like “words bear power” or “what you say will come true.” The reticular formation and the reticular activating system store thoughts and signals like these. Therefore, your focus is directed to those areas, and you actively start to build on those thoughts.
These structures filter what you are focusing on continuously. Therefore, if you keep thinking about a particular scenario or outcome, your brain will actively try to make that a reality. This reaction happens because our reticular activation system attempts to give us proof that our thoughts are correct. Furthermore, once those thoughts become a reality, it reinforces our beliefs that it is true. Therefore, we continue thinking that way.
Therefore, there is a connection between our thoughts, beliefs, actions, and reality. These behaviors and affinities are why the reticular activating system is referred to so often in psychology and motivational courses because they believe that you can control circumstances and their outcomes by beneficially using these systems. One of these methods is to project your subconscious thoughts to your conscious mind.
Clinical Significance Of The Reticular Formation
Damage to the reticular formation and its connections can lead to loss of consciousness and motor functions, leading to a coma or vegetative state. In addition, dysfunctions and deterioration of these systems can lead to symptoms that are the hallmark of various life-altering deceases. Furthermore, age tends to cause a general decline in reactivity in the reticular formation and the reticular activating system.
Symptoms Of Depression
Depression is a disorder related to your sense of being, well-being, and neurotransmitter function. This disorder can cause physical illness in a patient and have a fatal outcome in some scenarios. Therefore, dysfunctions of the reticular formation lead to disturbances in sleep patterns and appetite that can magnify the negative impact of the disorder. In addition, it can lead to libido and mood alterations.
Symptoms Of Schizophrenia
Many symptoms of schizophrenia, such as hallucinations, sleep-wake disturbances, and sensory gating abnormalities, are presumed to be due to abnormalities in the reticular activating system. First, the pedunculopontine nucleus sends signals to the substantia nigra. After that, dopaminergic sends projections to various striatum regions. With schizophrenia, the pedunculopontine nucleus has increased cholinergic neurons.
Symptoms Of Parkinson’s Disease
Parkinson’s diseaseis a progressive neurodegenerative disorder affecting the dopaminergic neurons. Therefore, leading to regular movement disruptions. Dysfunctions of the reticular formation are an integral component in developing this disorder. In addition, this disease decreases the function of the reticular formation, affecting your motor functions and sleep quality, disrupting the REM cycles
Symptoms Of Locked-In Syndrome
Locked-in- syndrome is a rare neurological disorder, also known as pseudocoma. With this disorder, a patient is fully conscious and aware as cognitive functions are usually unaffected. However, it paralyzes nearly all voluntary muscles in the entire body except for vertical eye movements and the ability to blink. Damage to the lower brain is the most common cause of this disorder, specifically, injury to the pons.
Treatment For Attention Deficit Hyperactivity Disorder
Some doctors believe that the reticular formation in the brainstem can play a vital role in treating patients with ADHD as it can help them remain focused, stay on task, make decisions, and follow through on those decisions.
Improve The Reticular Formation
Damage to the reticular formation caused by a severe brain injury’s general treatment is usually surgery, medication, or rehabilitation therapies. Furthermore, you can treat or lessen the symptoms of these diseases by using rehabilitation strategies that focus on improving the sleep-wake cycle. These treatment strategies include:
- Improving sleep hygiene – Changing behaviors and environmental conditions that generally disrupt your sleeping pattern can be widely beneficial.
- Cognitive-behavioral therapy can include relaxation training, sleep restrictions, and stimulus control.
Disorder Of Sleep-Wake Cycles
Disorders that have symptoms caused by defections and deterioration of the reticular formation include hypersomnia, narcolepsy, and post-traumatic stress disorder. In addition, symptoms of these diseases and conditions can include vivid dreams, inability to fall asleep, hallucinations, and inability to stay awake. Furthermore, these symptoms can have physical effects, including muscle paralysis and drowsiness.
Conclusion
The reticular formation is an integrated system of nuclei, fibers, and nerves responsible for various crucial brain functions vital to survival. In addition, it plays an essential role in controlling reflexive movements, posture, balance, consciousness, and respiration. Therefore, damage, deterioration, and destruction of the reticular formation can lead to severe diseases, a permanent unconscious state, or even death.
References
https://www.britannica.com/science/reticular-formation
https://psychology.fandom.com/wiki/Reticular_formation
https://www.nature.com/articles/sc2008105
https://www.frontiersin.org/articles/10.3389/fnana.2017.00051/full
