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Perihypoglossal Nuclei
{{one source, date=April 2012 Perihypoglossal nuclei (''nuclei perihypoglossales''), called also perihypoglossal complex or perihypoglossal nuclear complex or satellite nuclei is a group of neurons in the floor of the fourth ventricle, in close proximity to the nucleus of the hypoglossal nerve in the gray substance of the medulla oblongata, all of which contain cells with characteristics suggestive of reticular connections. The complex includes three nuclei: the intercalated nucleus, the nucleus prepositus, and the sublingual nucleus. The nucleus prepositus is the largest of the three. Perihypoglossal nuclei receive afferents from the cerebral cortex, vestibular nuclei, accessory oculomotor nuclei, and paramedian pontine reticular formation. Efferent fibers of these nuclei terminates in cranial nerve nuclei involved in extraocular movement (oculomotor, trochlear, abducens), the cerebellum, and the thalamus The thalamus (from Greek θάλαμος, "chamber") is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron, neurone, or nerve cell is an membrane potential#Cell excitability, electrically excitable cell (biology), cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all Animalia, animals except sponges and placozoa. Non-animals like plants and fungi do not have nerve cells. Neurons are typically classified into three types based on their function. Sensory neurons respond to Stimulus (physiology), stimuli such as touch, sound, or light that affect the cells of the Sense, sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to gland, glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are connected together, they form what is called a neural circuit. A typical neuron consists of a cell bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourth Ventricle
The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle. The fourth ventricle extends from the cerebral aqueduct (''aqueduct of Sylvius'') to the obex, and is filled with cerebrospinal fluid (CSF). The fourth ventricle has a characteristic diamond shape in cross-sections of the human brain. It is located within the pons or in the upper part of the medulla oblongata. CSF entering the fourth ventricle through the cerebral aqueduct can exit to the subarachnoid space of the spinal cord through two lateral apertures and a single, midline median aperture. Boundaries The fourth ventricle has a roof at its ''upper'' (posterior) surface and a floor at its ''lower'' (anterior) surface, and side walls formed by the cerebellar peduncles (nerve bundles joining the structure on the posteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoglossal Nucleus
The hypoglossal nucleus is a cranial nerve nucleus, found within the medulla. Being a motor nucleus, it is close to the midline. In the open medulla, it is visible as what is known as the ''hypoglossal trigone'', a raised area (medial to the vagal trigone) protruding slightly into the fourth ventricle. The hypoglossal nucleus is located between the dorsal motor nucleus of the vagus and the midline of the medulla. Axons from the hypoglossal nucleus pass anteriorly through the medulla forming the hypoglossal nerve which exits between the pyramid and olive in a groove called the anterolateral sulcus. See also * Hypoglossal nerve Additional images File:Gray695.png, Transverse section of medulla oblongata below the middle of the olive. File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral view. File:Medulla_oblongata_-_posterior_-_very_low_mag.jpg, Micrograph showing the hypoglossal nuclei in relation to their surrounding structures. Fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medulla Oblongata
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions, ranging from vomiting to sneezing. The medulla contains the cardiac, respiratory, vomiting and vasomotor centers, and therefore deals with the autonomic functions of breathing, heart rate and blood pressure as well as the sleep–wake cycle. During embryonic development, the medulla oblongata develops from the myelencephalon. The myelencephalon is a secondary vesicle which forms during the maturation of the rhombencephalon, also referred to as the hindbrain. The bulb is an archaic term for the medulla oblongata. In modern clinical usage, the word bulbar (as in bulbar palsy) is retained for terms that relate to the medulla oblongata, particularly in reference to medical conditions. The word bulbar can refer to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Formation
The reticular formation is a set of interconnected nuclei that are located in the brainstem, hypothalamus, and other regions. 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 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, basically act as an “on/off” switch to the cerebral cortex and hence 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 co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleus (neuroanatomy)
In neuroanatomy, a nucleus (: nuclei) is a cluster of neurons in the central nervous system, located deep within the cerebral hemispheres and brainstem. The neurons in one nucleus usually have roughly similar connections and functions. Nuclei are connected to other nuclei by tracts, the bundles (fascicles) of axons (nerve fibers) extending from the cell bodies. A nucleus is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up as a region of gray matter, often bordered by white matter. The vertebrate brain contains hundreds of distinguishable nuclei, varying widely in shape and size. A nucleus may itself have a complex internal structure, with multiple types of neurons arranged in clumps (subnuclei) or layers. The term "nucleus" is in some cases used rather loosely, to mean simply an identifiably distinct group of neurons, even if they are spr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intercalated Nucleus
Intercalated nucleus (''nucleus intercalatus'') called also Staderini nucleus is a group of nerve cells in the medulla oblongata, between the dorsal nucleus of the vagus nerve The dorsal nucleus of vagus nerve (or posterior nucleus of vagus nerve or dorsal vagal nucleus or nucleus dorsalis nervi vagi or nucleus posterior nervi vagi) is a cranial nerve nucleus for the vagus nerve in the medulla that lies ventral to the fl ... (lateral to the intercalated nucleus) and the nucleus of the hypoglossal nerve (medial to intercalated nucleus), forming part of the perihypoglossal nuclear complex. Function. Probably involved in the control of the vestibuloocular reflex and may contribute to the vertical neural integrator. Described for the first time in 1894 by Rutilio Staderini (1861–1942), Italian neuroanatomist References John Alan Kiernan, Murray Llewellyn Barr. ''Barr's The Human Nervous System: An Anatomical Viewpoint.'' 2008 {{Authority control Medulla oblongata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleus Prepositus
The nucleus prepositus (also nucleus prepositus hypoglossi), located in the caudal pons and upper medulla oblongata, contributes to several aspects of gaze control including the horizontal gaze holding system. It functions as a neural integrator An integrator in measurement and control applications is an element whose output signal is the time integral of its input signal. It accumulates the input quantity over a defined time to produce a representative output. Integration is an importan .... References Brainstem {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sublingual Nucleus
In the substance of the formatio reticularis are two small nuclei of gray matter. The one near the dorsal aspect of the hilus of the inferior olivary nucleus is called the Sublingual nucleus (inferior central nucleus, nucleus of Roller.) References External links NIF Search - Sublingual Nucleusvia the Neuroscience Information Framework Medulla oblongata {{Portal bar, Anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the cranium. Apart from minimising brain and cranial volume, cortical folding is crucial for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vestibular Nuclei
The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve located in the brainstem. In Terminologia Anatomica they are grouped in both the pons and the medulla in the brainstem. Structure Path The fibers of the vestibular nerve enter the medulla oblongata on the medial side of those of the cochlear, and pass between the inferior peduncle and the spinal tract of the trigeminal nerve. They then divide into ascending and descending fibers. The latter end by arborizing around the cells of the medial nucleus, which is situated in the area acustica of the rhomboid fossa. The ascending fibers either end in the same manner or in the lateral nucleus, which is situated lateral to the area acustica and farther from the ventricular floor. Some of the axons of the cells of the lateral nucleus, and possibly also of the medial nucleus, are continued upward through the inferior peduncle to the roof nuclei of the opposite side of the cerebellum, to which also other fibers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paramedian Pontine Reticular Formation
The paramedian pontine reticular formation, also known as PPRF or paraabducens nucleus, is part of the pontine reticular formation, a brain region without clearly defined borders in the center of the pons. It is involved in the coordination of eye movements, particularly horizontal gaze and saccades. Input, output, and function The PPRF is located anterior and lateral to the medial longitudinal fasciculus (MLF). It receives input from the superior colliculus via the predorsal bundle and from the frontal eye fields via frontopontine fibers. The rostral PPRF probably coordinates vertical saccades; the caudal PPRF may be the generator of horizontal saccades. In particular, activity of the excitatory burst neurons (EBNs) in the PPRF generates the "pulse" movement that initiates a saccade. In the case of horizontal saccades the "pulse" information is conveyed via axonal fibres to the abducens nucleus, initiating lateral eye movements. The angular velocity of the eye during horizonta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
