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Habenular Commissure
The habenular commissure is a nerve tract of commissural fibers that connects the habenular nuclei on both sides of the habenular trigone in the epithalamus. The habenular commissure is part of the habenular trigone (a small depressed triangular area situated in front of the superior colliculus and on the lateral aspect of the posterior part of the taenia thalami). The habenulum trigone also contains the habenular nuclei. Fibers enter the habenular trigone from the stalk of the pineal gland, and the habenular commissure. Most of the habenular trigone's fibers are, however, directed downward and form a bundle, the fasciculus retroflexus, which passes medial to the red nucleus, and, after decussating with the corresponding fasciculus of the opposite side, ends in the interpeduncular nucleus. External links NIF Search - Habenular commissurevia the Neuroscience Information Framework The Neuroscience Information Framework is a repository of global neuroscience web resources, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve Tract
A nerve tract is a bundle of nerve fibers (axons) connecting Nucleus (neuroanatomy), nuclei of the central nervous system. In the peripheral nervous system, this is known as a nerve fascicle, and has associated nervous tissue, connective tissue. The main nerve tracts in the central nervous system are of three types: association fibers, commissural fibers, and projection fibers. A nerve tract may also be referred to as a commissure, decussation, or neural pathway. A commissure connects the two cerebral hemispheres at the same levels, while a decussation connects at different levels (crosses obliquely). Types The nerve fibers in the central nervous system can be categorized into three groups on the basis of their course and connections. Different tracts may also be referred to as ''projections'' or ''radiations'' such as thalamocortical radiations. Association fibers The tracts that connect cortical areas within the same hemisphere are called Association fiber, association tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commissural Fiber
The commissural fibers or transverse fibers are axons that connect the two hemispheres of the brain. Huge numbers of commissural fibers make up the commissural tracts in the brain, the largest of which is the corpus callosum. In contrast to commissural fibers, association fibers form association tracts that connect regions within the same hemisphere of the brain, and projection fibers connect each region to other parts of the brain or to the spinal cord. Structure The commissural fibers make up tracts that include the corpus callosum, the anterior commissure, and the posterior commissure. Corpus callosum The corpus callosum is the largest commissural tract in the human brain. It consists of about 200–300 million axons that connect the two cerebral hemispheres. The corpus callosum is essential to the communication between the two hemispheres. A recent study of individuals with agenesis of the corpus callosum suggests that the corpus callosum plays a vital role in problem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habenular Nuclei
The habenula (diminutive of Latin meaning rein) is a small bilateral neuronal structure in the brain of vertebrates, that has also been called a microstructure since it is no bigger than a pea. The naming as little rein describes its elongated shape in the epithalamus, where it borders the third ventricle, and lies in front of the pineal gland. Although it is a microstructure each habenular nucleus is divided into two distinct regions of nuclei, a medial habenula (MHb), and a lateral habenula (LHb) both having different neuronal populations, inputs, and outputs. The medial habenula can be subdivided into five subnuclei, the lateral habenula into four subnuclei. Research has shown morphological complexity in the MHb and LHb. Different inputs to the MHb are discriminated between the different subnuclei. In the two regions of nuclei there is a difference in gene expression giving different functions to each. The habenula is a conserved structure across vertebrates. In mammals it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habenular Trigone
The habenular trigone is a small depressed triangular area situated (sources differ) anterior/superior to the superior colliculus. It contains the habenular nuclei. Anatomy The habenular trigone is situated on the lateral aspect of the posterior part of the taenia thalami In the front, superior surface of the thalamus but separate from the inner, medial surface by a salient margin is the taenia thalami (Latin for "flat band" of the thalamus). The bottom epithelial lining of the third ventricle is in between the tela .... References Habenula {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithalamus
The epithalamus (: epithalami) is a posterior (dorsal) segment of the diencephalon. The epithalamus includes the habenular nuclei, the stria medullaris, the anterior and posterior paraventricular nuclei, the posterior commissure, and the pineal gland. Functions The function of the epithalamus is to connect the limbic system to other parts of the brain. The epithalamus also serves as a connecting point for the dorsal diencephalic conduction system, which is responsible for carrying information from the limbic forebrain to limbic midbrain structures. Some functions of its components include the secretion of melatonin from the pineal gland (circadian rhythms), regulation of motor pathways and emotions, and how energy is conserved in the body. A study has shown that the lateral habenula, in the epithalamus, produces spontaneous theta oscillatory activity that was correlated with theta oscillation in the hippocampus. The same study also found that the increase in theta waves in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taenia Thalami
In the front, superior surface of the thalamus but separate from the inner, medial surface by a salient margin is the taenia thalami (Latin for "flat band" of the thalamus). The bottom epithelial lining of the third ventricle is in between the tela choroidea The tela choroidea (or tela chorioidea) is a region of meninges, meningeal pia mater that adheres to the underlying ependyma, and gives rise to the choroid plexus in each of the brain’s Ventricular system, four ventricles. ''Tela'' is Latin for ... and the taenia thalami. References Thalamus {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habenular Nuclei
The habenula (diminutive of Latin meaning rein) is a small bilateral neuronal structure in the brain of vertebrates, that has also been called a microstructure since it is no bigger than a pea. The naming as little rein describes its elongated shape in the epithalamus, where it borders the third ventricle, and lies in front of the pineal gland. Although it is a microstructure each habenular nucleus is divided into two distinct regions of nuclei, a medial habenula (MHb), and a lateral habenula (LHb) both having different neuronal populations, inputs, and outputs. The medial habenula can be subdivided into five subnuclei, the lateral habenula into four subnuclei. Research has shown morphological complexity in the MHb and LHb. Different inputs to the MHb are discriminated between the different subnuclei. In the two regions of nuclei there is a difference in gene expression giving different functions to each. The habenula is a conserved structure across vertebrates. In mammals it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pineal Gland
The pineal gland (also known as the pineal body or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin-derived hormone, which modulates sleep, sleep patterns following the diurnal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two cerebral hemisphere, hemispheres, tucked in a groove where the two halves of the thalamus join. It is one of the neuroendocrinology, neuroendocrine Circumventricular organs, secretory circumventricular organs in which capillaries are mostly Vascular permeability, permeable to solutes in the blood. The pineal gland is present in almost all vertebrates, but is absent in Protochordata, protochordates in which there is a simple pineal homologue. The hagfish, archaic vertebrates, lack a pineal gland. In some species of amphibians and reptiles, the gland is linked to a light-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fasciculus Retroflexus
The fasciculus retroflexus (FR) also known as the habenulointerpeduncular tract is a bundle of fibers located at the base of the midbrain in vertebrates. Connected to the habenula (Hbn) and the interpeduncular nucleus (IPN), the fasciculus retroflexus is involved in a variety of bodily phenomena, some being sleep retention. and drug addiction. It acts as a channel through which messages are sent between the stria medullaris and the mid- and hindbrain. The fasciculus retroflexus, along with the stria medullaris, the habenula, and the medial forebrain bundle forms a unit for the transfer of neurological impulses. In this unit, the fasciculus retroflexus mediates the transfer of information for processes such as pain, pleasure, and motor control Anatomy The fasciculus retroflexus is the main efferent track of the habenula. The FR is an extremely condensed bundle of fibers which consists of two concentric regions. The first of these is the inner fibers of the FR, beginning at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Nucleus
The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. The structure is located in the midbrain tegmentum next to the substantia nigra and comprises caudal magnocellular and rostral parvocellular components. The red nucleus and substantia nigra are subcortical centers of the extrapyramidal motor system. Function In a vertebrate without a significant corticospinal tract, gait is mainly controlled by the red nucleus. However, in primates, where the corticospinal tract is dominant, the rubrospinal tract may be regarded as vestigial in motor function. Therefore, the red nucleus is less important in primates than in many other mammals. Nevertheless, the crawling of babies is controlled by the red nucleus, as is arm swinging in typical walking. The red nucleus may play an additional role ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interpeduncular Nucleus
The interpeduncular nucleus (IPN) is an unpaired, ovoid group of neurons at the base of the midbrain tegmentum. In the midbrain it lies below the interpeduncular fossa. As the name suggests, the interpeduncular nucleus lies ''in between'' the cerebral peduncles. Composition The Interpeduncular nucleus is primarily GABAergic and contains at least two neuron clusters of different morphologies. The region is divided into 7 paired and unpaired subnuclei Subdivisions The presence of non-homologous subdivisions of the Interpeduncular nucleus was first noticed by Santiago Ramón y Cajal, Cajal over a hundred years ago. The currently recognized standard subdivision notation was mostly established by Hammill and Lenn in 1984 by combining the work and notations of four groups. Although most of their proposed convention stuck, at some point the proposed "rostral lateral" sub-nucleus was renamed "dorsomedial" and became immortalized in brain atlases. * Apical sub-nucleus (IPA) Unpaired sub-nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroscience Information Framework
The Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/ genomic resources and provides many authoritative links throughout the neuroscience portal of Wikipedia. Description The Neuroscience Information Framework (NIF) is an initiative of the NIH Blueprint for Neuroscience Research, which was established in 2004 by the National Institutes of Health. Development of the NIF started in 2008, when the University of California, San Diego School of Medicine obtained an NIH contract to create and maintain "a dynamic inventory of web-based neurosciences data, resources, and tools that scientists and students can access via any computer connected to the Internet". The project is headed by Maryann Martone, co-director of the National Center for Microscopy and Imaging Research (NCMIR), part of the multi-disciplinary Center for Research in Bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
