reticular formation


Also found in: Dictionary, Thesaurus, Financial, Encyclopedia, Wikipedia.

re·tic·u·lar for·ma·tion (RF),

a massive but vaguely delimited neural apparatus composed of closely intermingled gray and white matter and extending throughout the central core of the brainstem and into the diencephalon; the term refers to the large neuronal population of the brainstem that does not comprise motoneuronal cell groups or cell groups forming part of specific sensory conduction systems; its neurons generally have long dendrites and heterogeneous afferent connections, which is why the formation is often called "nonspecific"; the reticular formation has complex, largely polysynaptic ascending and descending connections that play a role in the central control of autonomic (for example, respiration, blood pressure, and thermoregulation) and endocrine functions, as well as in bodily posture, skeletomuscular reflex activity, and general behavioral states such as alertness and sleep.

reticular formation

n.
A diffuse network of white longitudinal nerve fibers interspersed with gray matter, located in the brainstem, that regulates various autonomic functions, such as sleep and waking.

re·tic·u·lar for·ma·tion

(rĕ-tik'yū-lăr fōr-mā'shŭn)
A massive but vaguely delimited neural apparatus composed of gray and white matter extending throughout the central core of the brainstem into the diencephalon; the large neuronal population of the brainstem that does not compose motoneuronal cell groups or cell groups forming part of specific sensory conduction systems; its neurons generally have long dendrites and heterogeneous afferent connections; the reticular formation has complex, largely polysynaptic ascending and descending connections that play a role in the central control of autonomic (respiration, blood pressure, thermoregulation) and endocrine functions, as well as in bodily posture, skeletal muscle reflexes, and general behavioral states such as alertness and sleep.
Synonym(s): formatio reticularis [TA] , reticular substance (2) .
[L. formatio reticularis]

reticular formation

A network of islets of grey matter, consisting of large and small nerve cells and their connections, scattered throughout the brainstem and extending into the THALAMUS and HYPOTHALAMUS. The formation receives information from many other parts of the brain and is concerned with alertness and direction of attention to external events, as well as sleep. It has a major effect on the sensory and motor systems.

reticular formation

the part of the CNS that consists of small islands of grey matter separated by fine bundles of nerve fibres running in all directions.
References in periodicals archive ?
EEG signals were recorded from frontal cortex, hippocampus, striatum and reticular formation from inside a totally copper shielded room.
As for other EF system structures, it has also been found that the superior colliculus is a prominent way-station in the brain's orienting network (discussed in the context of Posner's attentional theory, below), receiving projections from the striatum via the substantia nigra (Posner & Raichle, 1994; Ungerstedt, 1974), as well as from the pontine reticular formation (Nauta & Kuypers, 1958), with which it has reciprocal connections (Voneida, 1974).
BDA (1 [micro]l of 10% BDA dissolved in 0.01 M PB) was pressure injected manually into the right gigantocellular (Gi) nucleus of the reticular formation in the brainstem using a stereotaxic frame (coordinates: 0.8 mm lateral to the midline, 2.8 mm caudal to the interaural line, and 7.6 mm deep) with a 10 [micro]l Hamilton syringe (26 s with an outer diameter of 0.47 mm and an inner diameter of 0.13 mm; Figures 1(b) and 1(c)).
DISCUSSION: The "Vomiting Centre" is an ill-defined area located in the lateral reticular formation of the medulla oblongata 6.
* Cerebral cortex [] * Occipital lobe [] * Cerebellum [] * Reticular formation [] * Hypothalamus [] 3.
Due to lesion in the MLF, ipsilateral medial rectus fails to receive the signal to contract when paramedian pontine reticular formation (PPRF) and sixth nerve nucleus act to intiate lateral gaze.
High densities of opioid receptors are located in all areas of the central nervous system known to be involved in integrating information about pain such as cingulate cortex, periaqueductal gray matter and reticular formation (8) and, these major structures of the medial pain system have a very high concentration of opioid receptors (5).
From there they project into the LC and other areas such as the reticular formation and the raphe nuclei, which play a role in REM sleep.
The activity of REM sleep related neurons is modulated by wakefulness (midbrain reticular formation/ascending reticular activating system) and sleep inducing (caudal brainstem/medullary reticular formation) areas.
For this second edition, new chapters have been added on reticular formation, control of posture and movement, and the patient with neurologic disorder.
In the adult, the motor nucleus of the facial nerve (VIIIth cranial nerve) is located deep in the reticular formation of the caudal portion of the pons.
Distractibility, an executive function deficit, appears to involve dopaminergic and noradrenergic systems in the reticular formation, prefrontal cortex, and corpus callosum, and is best treated with methylphenidate or dextroamphetamine, he said.