Brain: Reticular formation
Coronal section of the pons, at its upper part. (Formatio reticularis labeled at left.)
Section of the medulla oblongata at about the middle of the olive. (Formatio reticularis grisea and formatio reticularis alba labeled at left.)
Latin	formatio reticularis
Gray's	subject #187 784
NeuroNames	ancil-225
MeSH	Reticular+Formation
Dorlands/Elsevier	f_13/12374790

The reticular formation is a part of the brain which is involved in stereotypical actions, such as walking, sleeping, and lying down. It is absolutely essential for the basic functions of life and is phylogenetically one of the oldest portions of the brain. Image File history File links Gray701. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... Image File history File links Gray694. ... The medulla oblongata is the lower portion of the brainstem. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... NeuroNames is a system of nomenclature for the brain and related structures. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo. ... In animals the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... An animated demonstration of a six-legged insect walking. ... Sleeping girl Sleep is the fundamental anabolic process common to all life forms, plant and animal. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ...

Location and relations

It is a poorly-differentiated area of the brain stem, centered roughly in the pons. The ascending reticular activating system connects to areas in the thalamus, hypothalamus, and cortex, while the descending reticular activating system connects to the cerebellum and sensory nerves. Mostly enveloped by the cerebrum and cerebellum (blue), the visible part of brainstem is shown in black. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... The reticular activating system is the name given to part of the brain (the Reticular Formation and its connections) believed to be the centre of arousal and motivation in animals (including humans). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The hypothalamus (from Greek ὑποθαλαμος = under the thalamus) is a region of the mammalian brain located below the thalamus, forming the major portion of the ventral region of the diencephalon and functioning to regulate certain metabolic processes and other autonomic activities. ... Look up cortex in Wiktionary, the free dictionary. ... Figure 1a: A human brain, with the cerebellum in purple. ... The mechanism of the reflex arc Sensory neurons (or neurones) are nerve cells within the nervous system responsible for converting external stimuli from the organisms environment into internal electrical impulses. ...

Functions

The RF appears to not only control physical behaviors such as sleep, but also has been shown to play a major role in alertness, fatigue, and motivation to perform various activities. Some researchers have speculated that the reticular formation controls approximately 25 specific behaviors, including sleeping, walking, eating, urination, defecation, and sexual activity^{[citation needed]}. Sleep is the state of natural rest observed in most mammals, birds, fish, as well as invertebrates such as the fruitfly Drosophila. ... Sleeping girl Sleep is the fundamental anabolic process common to all life forms, plant and animal. ... An animated demonstration of a six-legged insect walking. ... // For eat or EAT as an abbreviation or acronym, see EAT. In general terms, eating (formally, ingestion) is the process of consuming nutrition, i. ... Urination, also called micturition, is the process of disposing urine from the urinary bladder through the urethra to the outside of the body. ... This article or section does not cite its references or sources. ... Sexual behavior is a form of physical intimacy that may be directed to reproduction (one possible goal of sexual intercourse) and/or to the enjoyment of activity involving sexual gratification. ...

The reticular formation has also been traced as one of the sources for the introversion and extroversion character traits. Introverted people have been found to have a more easily stimulated reticular formation, resulting in a diminished desire to seek out stimulus. Extroverted people, however, have a less easily stimulated reticular formation, resulting in the need for more stimulation to maintain brain activity^{[citation needed]}. The terms introvert and extrovert (also spelled extravert) refer to a personality factor expressed in traits such as warmth, gregariousness, assertiveness, activity, and excitement seeking. ...

Pathology

Lesions in the reticular formation have been found in the brains of people who have post-polio syndrome, and some imaging studies have shown abnormal activity in the area in people with chronic fatigue syndrome, indicating a high likelihood that damage to the reticular formation is responsible for the fatigue experienced with these syndromes. Post-polio syndrome (PPS) is a condition that frequently affects survivors of poliomyelitis, a viral infection of the nervous system, after recovery from an initial paralytic attack of the virus. ... Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), post-viral fatigue syndrome (PVFS), and various other names, is a syndrome (or group of syndromes) of unknown and possibly multiple etiologies, affecting the central nervous system (CNS), immune, and many other systems and organs. ...

History and etymology

The term "reticular formation" was coined in the late 19th century, coinciding with Ramon y Cajal’s "neuron doctrine". Allan Hobson states in his book The Reticular Formation revisited that he thought the name was an etymological vestige from the fallen era of the aggregate field theory in the neural sciences. The term reticulum means a “netlike structure”, which is what the Reticular Formation appears to be at first glance. It has been described as being either too complex to study or an undifferentiated part of the brain with no organization at all. Eric Kandel even describes the reticular formation as being organized in a similar manner to the intermediate gray matter of the spinal cord. This chaotic, loose and intricate form of organization is what has turned off many researchers from looking farther into this mysterious area of the brain which seems to be at the crux of our basic neurological and behavioral functions. The cells lack clear ganglionic boundaries, but do have clear functional organizations and distinct cell types. ... Ramón y Cajals drawing of the cells of the chick cerebellum, from Estructura de los centros nerviosos de las aves, Madrid, 1905. ... Dr. J. Allan Hobson // James Allan Hobson, M.D. (June 3, 1933 – 20--) is a Harvard psychiatrist and dream researcher who grew up in Hartford Connecticut. ... Eric Richard Kandel (born November 7, 1929) is a neuroscientist who won a Nobel Prize in the year 2000 for his research on the physiological basis of memory storage in neurons. ...

The term 'reticular formation' is seldom used anymore except to speak in generalities. Modern anatomy, or neuroscience articles usually refer to the individual nuclei which make up the reticular formation.

Structure

Taken from "The Brainstem Reticular Formation and its Significance for Autonomic and Affective Behavior". The above diagram illustrates the reticular nuclei in the brainstem in a tiered fashion

The reticular formation has been functionally cleaved both sagittally and coronally. Image File history File links Download high-resolution version (750x931, 668 KB)a nice look at the nuclei involved in the reticular formation The copyright status of this work is undetermined and may be difficult or impossible to determine. ... Image File history File links Download high-resolution version (750x931, 668 KB)a nice look at the nuclei involved in the reticular formation The copyright status of this work is undetermined and may be difficult or impossible to determine. ... The anatomical planes The anatomical position is a schematic convention for describing the relative morphology of the human body. ... (Linguistics) Coronals refer to Coronal consonants. ...

• The original functional differentiation was a division of caudal and rostral, this was based upon the observation that the lesioning of the rostral reticular formation induced a hypersomnia in the cat brain. Conversely, lesioning of the more caudal portion of the reticular formation produced insomnia in cats. This study has led to the idea that the caudal portion inhibits the rostral portion of the reticular formation.

• Sagittal division reveals more morphological distinctions. The raphe nuclei form a ridge in the middle of the reticular formation and directly to its periphery there is a division called the medial reticular formation. The medial RF is large and has long ascending and descending fibers, and is surrounded by the lateral reticular formation. The lateral RF is close to the motor nuclei of the cranial nerves, and mostly mediates their function.

In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... Hypersomnia, also known as excessive daytime sleepiness (EDS), is excessive amount of sleepiness. ... This article is about the sleeping disorder. ... The raphe nuclei (Latin for the bit in a fold or seam) is a moderately sized cluster of nuclei found in the brain stem, and releases serotonin to the rest of the brain. ...

Medial and lateral reticular formation

The medial reticular formation and lateral reticular formation are two columns of neuronal nuclei with ill-defined boundaries which go up through from the medulla and into the mesencephalon. The nuclei can only be teased out by function, cell type and projections of efferent or afferent nature. Surrounding the previously discussed ridge of serotonergic cells, the medial reticular formation has many roles and functions. ... Moving caudally from the rostral midbrain, at the site of the rostral pons and the midbrain, the medial RF becomes less prominent, and the lateral RF becomes more prominent. ... The medulla oblongata is the lower portion of the brainstem. ... In biological anatomy, the mesencephalon (or midbrain) is the middle of three vesicles that arise from the neural tube that forms the brain of developing animals. ... The mechanism of the reflex arc In the nervous system, efferent nerves – otherwise known as motor or effector neurons – carry nerve impulses away from the central nervous system to effectors such as muscles or glands (and also the ciliated cells of the inner ear). ... The mechanism of the reflex arc In the nervous system, afferent neurons--otherwise known as sensory or receptor neurons--carry nerve impulses from receptors or sense organs toward the central nervous system. ...

See also

• Raphe nuclei
• Locus coeruleus
• Pedunculopontine nucleus

The raphe nuclei (Latin for the bit in a fold or seam) is a moderately sized cluster of nuclei found in the brain stem, and releases serotonin to the rest of the brain. ... The Locus ceruleus, also spelled locus coeruleus, (Latin for the blue bit) is a nucleus in the brain stem apparently responsible for the physiological reactions involved in stress and panic. ... The pedunculopontine nucleus (PPN) is located in the brainstem, caudal to the substantia nigra and adjacent to the superior cerebellar peduncle. ...

Additional images

Deep dissection of brain-stem. Ventral view. Image File history File links Download high-resolution version (500x709, 127 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Substantia nigra Human thalamus Wikipedia:Grays Anatomy images with missing articles 14 Medial lemniscus Lateral lemniscus Reticular...

The formatio reticularis of the medulla oblongata, shown by a transverse section passing through the middle of the olive. Image File history File links Gray700. ... The medulla oblongata is the lower portion of the brainstem. ... Binomial name Olea europaea L. 19th century illustration The Olive (Olea europaea) is a species of small tree in the family Oleaceae, native to coastal areas of the eastern Mediterranean region, from Lebanon and the maritime parts of Asia Minor and northern Iran at the south end of the Caspian...