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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 the part of the reticular formation in the midbrain. It consists 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Formation
The reticular formation is a set of interconnected nuclei in the brainstem that spans from the lower end of the medulla oblongata to the upper end of the midbrain. The neurons of the reticular formation make up a complex set of neural networks in the core of the brainstem. The reticular formation is made up of a diffuse net-like formation of reticular nuclei which is not well-defined. It may be seen as being made up of all the interspersed cells in the brainstem between the more compact and named structures. The reticular formation is functionally divided into the ascending reticular activating system (ARAS), ascending pathways to the cerebral cortex, and the descending reticular system, descending pathways ( reticulospinal tracts) to the spinal cord. Due to its extent along the brainstem it may be divided into different areas such as the midbrain reticular formation, the central mesencephalic reticular formation, the pontine reticular formation, the paramedian pontine reticul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midbrain
The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation.Breedlove, Watson, & Rosenzweig. Biological Psychology, 6th Edition, 2010, pp. 45-46 The name ''mesencephalon'' comes from the Greek ''mesos'', "middle", and ''enkephalos'', "brain". Structure The midbrain is the shortest segment of the brainstem, measuring less than 2cm in length. It is situated mostly in the posterior cranial fossa, with its superior part extending above the tentorial notch. The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostral and caudal, Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while Rostral and caudal, cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Tegmental Nucleus
The dorsal tegmental nucleus (DTN), also known as dorsal tegmental nucleus of Gudden, is a group of neurons located in the brainstem, 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, and glutamatergic neurons which project to mammillary. Circuitry As part of the Papez circuit The Papez circuit ,Livingston, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Tegmental Nucleus
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. 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 axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, ''Terminologia Anato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cuneiform Nucleus
Cuneiform is a logo-syllabic writing system that was used to write several languages of the Ancient Near East. The script was in active use from the early Bronze Age until the beginning of the Common Era. Cuneiform scripts are marked by and named for the characteristic wedge-shaped impressions (Latin: ) which form their signs. Cuneiform is the earliest known writing system and was originally developed to write the Sumerian language of southern Mesopotamia (modern Iraq). 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 ar ... [...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 tegmentum (from Latin for "covering") is a general area within the brainstem. The tegmentum is the ventral part of the midbrain and the tectum is the dorsal part of the midbrain. It is located between the ventricular system and distinctive b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammillotegmental Fasciculus
The mammillotegmental fasciculus (mammillotegmental tract, or mammillotegmental bundle of Gudden) 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 at the dorsal and ventral tegmental nuclei and the tegmental pontine reticular nucleus The tegmentum (from Latin for "covering") is a general are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammillothalamic Tract
The mammillothalamic tract (MMT) (also mammillary fasciculus, mammillothalamic fasciculus, thalamomammillary fasciculus, bundle of Vicq d'Azyr) is an efferent pathway of the mammillary bodies which project to the anterior nuclei of the thalamus. The mammillothalamic tract is part of the Papez circuit (involved in spatial memory), starting and finishing in the hippocampus.Shah, A., Jhawar, S. S., & Goel, A. (2012). Analysis of the anatomy of the Papez circuit and adjoining limbic system by fiber dissection techniques. rticle Journal of Clinical Neuroscience, 19(2), 289-298. . The fibers of the MMT are heavily myelinated. It arises from the medial and lateral nuclei of the mammillary bodies, and from fibers that are directly continued from the fornix of the hippocampus. It connects the mammillary bodies to the dorsal tegmental nuclei, the ventral tegmental nuclei, and the anterior thalamic nuclei. Structure Axons divide within the gray matter; the thicker fibres form the MT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothalamotegmental Tract
The hypothalamotegmental tract is a pathway from the hypothalamus to the reticular formation. Axons from the posterior hypothalamus descend through the midbrain and pontine reticular formation. 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 can only be seen with special staining. 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 the part of the reticular formation in th ... 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 one of the two components of the medial (efferent/motor) zone of the pontine reticular formation - the other being the caudal pontine reticular nucleus. The efferents of these two structures together give rise to the medial (pontine) reticulospinal tract (which modulates the muscle tone of the trunk and limb musculature). A population of their neurons together also form the paramedian pontine reticular formation which is involved in the coordination of horizontal conjugate eye movements in response to head movements. Anatomy This nucleus tapers rostrally to transition into the caudal mesencephalic reticular formation. It contains sporadic giant neurons. Afferents It receives sensory and motor cortical afferents via corticoreticular fibers. Research Different populations of the pontis oralis have displayed discharge patterns which coordinate with phasic movements to and from paradoxical sleep. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantocellular Reticular Nucleus
The gigantocellular reticular nucleus (also magnocellular reticular nucleus) is the (efferent/motor) medial zone of the reticular formation of the caudal pons and rostral medulla oblongata. It consists of a substantial number of giant neurons, but also contains small and medium sized neurons. It gives rise to the lateral (medullary) reticulospinal tract which influences muscle tone of limb and trunk muscles, is involved in coordination of head-eye movements, promotes parasympathetic reduction of heart rate to decrease blood pressure, induces inspiration, and participates in the descending pain-inhibiting pathway. Anatomy Afferents It receives connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. It receives afferent corticoreticular fibers from the premotor cortex and supplementary motor area which modulate the activity of reticulospinal and reti ... [...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] |
