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Midbrain Reticular Formation
The midbrain reticular formation (MRF), also known as reticular formation of midbrain, mesencephalic reticular formation, tegmental reticular formation, and formatio reticularis (tegmenti) mesencephali, is a structure in the midbrain consisting of the dorsal tegmental nucleus, ventral tegmental nucleus, and cuneiform nucleus. These are also known as the tegmental nuclei.NeuroNamestegmental nuclei BrainInfo. Accessed January 25, 2011. The dorsal and ventral tegmental nuclei receive connections from the mammillo-tegmental ''bundle of Gudden'', a branch of the mammillothalamic tract. The bundle of Gudden might be identical to the hypothalamotegmental tract. Along with the oral pontine reticular nucleus, the midbrain reticular formation projects to the gigantocellular reticular nucleus. The midbrain reticular formation is the point at which the different algedonic signals come together, ensuring that the organism is aware of potential threats. See also *Hypothalamotegmental tract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midbrain
The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', "middle", and ''enkephalos'', "brain". Structure The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while caudally it adjoins the hindbrain (pons, medulla and cerebellum). In the rostral direction, the midbrain noticeably splays laterally. Sectioning of the midbrain is usually performed axially, at one of two levels – that of the superior colliculi, or that of the inferior colliculi. One common technique for remembering the structures of the midbrain involves visualizing these cross-sections (especially at the level of the superior colliculi) as the upside-down face of a be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Tegmental Nucleus
The dorsal tegmental nucleus (DTN), also known as dorsal tegmental nucleus of Gudden (DTg), is a group of neurons located in the brain stem, which are involved in spatial navigation and orientation. Anatomy The dorsal tegmental nucleus is located in the brain stem near the midline. Two nuclei exist in both hemispheres. The DTN is generally subdivided into four parts called partes centralis, ventromedialis, anterior, and posterior. DTN contains a dense population of GABAergic cells. In the rat, few also express calbindin (CB) or calretinin (CR). Many of the DTN GABAergic cells do express parvalbumin (PV) with the densest expression in the pars ventralis portion. DTN neurons in rats contain small number of neuropeptide Y positive (NPY) neurons implicating a role in hunger and feeding. In rats, the DTN contains a small number of enkephalin, substance p Substance P (SP) is an undecapeptide (a peptide composed of a chain of 11 amino acid residues) and a member of the tachykinin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Tegmental Nucleus
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cuneiform Nucleus
Cuneiform is a logo-syllabic script that was used to write several languages of the Ancient Middle East. The script was in active use from the early Bronze Age until the beginning of the Common Era. It is named for the characteristic wedge-shaped impressions (Latin: ) which form its signs. Cuneiform was originally developed to write the Sumerian language of southern Mesopotamia (modern Iraq). Cuneiform is the earliest known writing system. Over the course of its history, cuneiform was adapted to write a number of languages in addition to Sumerian. Akkadian texts are attested from the 24th century BC onward and make up the bulk of the cuneiform record. Akkadian cuneiform was itself adapted to write the Hittite language in the early second millennium BC. The other languages with significant cuneiform corpora are Eblaite, Elamite, Hurrian, Luwian, and Urartian. The Old Persian and Ugaritic alphabets feature cuneiform-style signs; however, they are unrelated to the cuneiform logo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tegmental Nucleus (other)
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Tegmental nucleus may refer to: * Laterodorsal tegmental nucleus * Pedunculopontine nucleus or pedunculopontine tegmental nucleus * Rostromedial tegmental nucleus * Tegmental pontine reticular nucleus The reticulotegmental nucleus, tegmental pontine reticular nucleus (or pontine reticular nucleus of the tegmentum) is an area within the floor of the pons, in the brain stem. This area is known to affect the cerebellum with its axonal projections. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammillotegmental Fasciculus
The mammillotegmental fasciculus (or mammillotegmental tract, mammillo-tegmental bundle of Gudden, or ''Fasciculus mammillotegmentalis'') is a small bundle of efferent fibers from the hypothalamus running from the mammillary body to the tegmentum. Its functions are not well defined for humans, but based on animal studies it seems to be related to regulating visceral function and processing spatial information. The mammillotegmental fasciculus was first described by the German neuroanatomist, Bernhard von Gudden, from which it takes its alternate name, mammillo-tegmental bundle of Gudden. The mammillotegmental fasciculus emerges from the principal mammillary fasciculus of the mammillary body and travels dorsally together with the mammillothalamic tract before splitting off and turning caudally to enter the spinal column. There, it terminates in the tegmentum of the midbrain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with visio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammillothalamic Tract
The mammillothalamic tract (mammillothalamic fasciculus, thalamomammillary fasciculus, bundle of Vicq d’Azyr) arises from cells in both the medial and lateral nuclei of the mammillary body and by fibers that are directly continued from the fornix. The mammillothalamic tract then connects the mammillary body to the dorsal tegmental nuclei, the ventral tegmental nuclei, and the anterior thalamic nuclei. Structure The mammillothalamic tract was first described by the French physician, Félix Vicq d'Azyr, from whom it takes its alternate name (bundle of Vicq d'Azyr). There, axons divide within the gray matter; the coarser branches pass into the anterior nucleus of the thalamus as the ''bundle of Vicq d’Azyr''. The finer branches pass downward as the mammillotegmental ''bundle of Gudden''. The bundle of Vicq d’Azyr spreads fan-like as it terminates in the medial dorsal nucleus. Some fibers pass through the dorsal nucleus to the angular nucleus of the thalamus. ("The term 'a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothalamotegmental Tract
In human neuroanatomy, the hypothalamotegmental tract is a pathway from the hypothalamus to the reticular formation. Axons from the posterior hypothalamus descend through the mesencephalic and pontine reticular formations. They connect with reticular neurons important in visceral and autonomic activity. The tract is a continuation of the medial forebrain bundle in the lateral portion of the tegmentum. It is not visible without special stains. See also *Mammillothalamic tract *Medial forebrain bundle *Midbrain reticular formation The midbrain reticular formation (MRF), also known as reticular formation of midbrain, mesencephalic reticular formation, tegmental reticular formation, and formatio reticularis (tegmenti) mesencephali, is a structure in the midbrain consisting of ... References Hypothalamus {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Pontine Reticular Nucleus
The oral pontine reticular nucleus, or rostral pontine reticular nucleus, is delineated from the caudal pontine reticular nucleus. This nucleus tapers into the lower mesencephalic reticular formation and contains sporadic giant cells. Different populations of the pontis oralis have displayed discharge patterns which coordinate with phasic movements to and from paradoxical sleep. From this information it has been implied that the n.r. pontis oralis is involved in the mediation of changing to and from REM sleep Rapid eye movement sleep (REM sleep or REMS) is a unique phase of sleep in mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream viv ....Dergacheva OIu et al. Impulse activity of neurons in the nucleus pontis oralis in cats during sleep--wakefulness cycle. Ross Fiziol Zh Im I M Sechenova. 2002 Dec;88(12):1530-7. References Pons Neuroscience of sleep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Formation
The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cerebral cortex, cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts. Neurons of the reticular formation, particularly those of the ascending reticular activating system, play a crucial role in maintaining behavioral arousal and consciousness. The overall functions of the reticular formation are modulatory and premotor, involving somatic motor control, cardiovascular control, pain modulation, sleep and consciousness, and habituation. The modulatory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantocellular Reticular Nucleus
The gigantocellular reticular nucleus (Gi) is a subregion of the medullary reticular formation. As the name indicates, it consists mainly of so-called giant neuronal cells. This nucleus has been known to innervate the caudal hypoglossal nucleus, and responds to glutamatergic stimuli. The gigantocellular nucleus excites the hypoglossal nucleus, and can play a role in the actions of the said nerve.Yang, CC et al. Excitatory innervation of caudal hypoglossal nucleus from nucleus reticularis gigantocellularis in the rat. Neuroscience. 1995 Mar;65(2):365-74. It additionally receives connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. Retrograde studies have shown that the deep mesencephalic reticular formation and oral pontine reticular nucleus project to the gigantocellular nucleus. The dorsal rostral section of the nucleus reticularis gigantocellularis is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algedonic Signal
An algedonic signal is a pre-emptive message concerning pleasure or pain. An arousal mechanism can generate an algedonic signal, and thus provide an important survival mechanism to a living organism by alerting it to a threat. An example of the disastrous consequences of such a system not being in place is that of a moth attracted by the light of an open flame without recognising the danger of fire. In the human nervous system a variety of algedonic signals are brought together in the midbrain reticular formation from across the whole body. A source of pain, such as touching a burning surface or treading on broken glass, creates such an algedonic signal which interrupts consciousness and provokes a reflex action In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs .... References {{reflist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
