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Allothalamus
The Allothalamus is a division used by some researchers in describing the thalamus. Paramedian formation This or periventricular formation lies along the wall of the third ventricle. In man where there is no or almost no adhaesio interthalamica this is reduced to a thin layer medial to the medial nucleus. This lamina has no clear subdivisions and the formation may be seen as one entity. Contrarily to the isothalamus it stains for numerous mediators. Its connections are not really known, participating in periventricular systems. Intralaminar-limitans formation Il-Li This does not include the central region (centre-median, see below). Along with the paramedian formation, it makes a kind of capsule around the medial nucleus ("circular nucleus"). Together they are deeply regressive structures in evolution. Only its anterior part is clearly present in humans. Caudally, dorsal to the central region it breaks into small islands. Some of them are just posterior to the central complex. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, known as the thalamocortical radiations, allowing hub (network science), hub-like exchanges of information. It has several functions, such as the relaying of sensory neuron, sensory and motor neuron, motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness. Anatomically, the thalami are paramedian symmetrical structures (left and right), within the vertebrate brain, situated between the cerebral cortex and the midbrain. It forms during embryonic development as the main product of the diencephalon, as first recognized by the Swiss embryologist and anatomist Wilhelm His Sr. in 1893. Anatomy The thalami ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periventricular Nucleus
The periventricular nucleus is a thin sheet of small neurons located in the wall of the third ventricle, a composite structure of the hypothalamus. It functions in analgesia. It is located in the rostral, intermediate, and caudal regions of the hypothalamus. The rostral region aids in the production of both somatostatin and thyroid releasing hormone. The intermediate portion aids in production of thyroid releasing hormone, somatostatin, leptin, gastrin, and neuropeptide Y. In humans and primates it also produces GnRH. Lastly the caudal region aids in sympathetic nervous system regulation, and is regarded as the rage center. The periventricular nucleus does not have an effective blood–brain barrier. 11β-HSD2 expression turns cortisol into cortisone. Role in LH and GnRH release This nucleus has been shown to affect the release of GnRH (gonadotropin-releasing hormone) in several ways. One way is its expression of neuropeptide Y, which has an impact on the hypothalami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striatum
The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamatergic and dopaminergic inputs from different sources; and serves as the primary input to the rest of the basal ganglia. Functionally, the striatum coordinates multiple aspects of cognition, including both motor and action planning, decision-making, motivation, reinforcement, and reward perception. The striatum is made up of the caudate nucleus and the lentiform nucleus. However, some authors believe it is made up of caudate nucleus, putamen, and ventral striatum. The lentiform nucleus is made up of the larger putamen, and the smaller globus pallidus. Strictly speaking the globus pallidus is part of the striatum. It is common practice, however, to implicitly exclude the globus pallidus when referring to striatal structures. In pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substantia Nigra
The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas due to high levels of neuromelanin in dopaminergic neurons. Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the substantia nigra appears as a continuous band in brain sections, anatomical studies have found that it actually consists of two parts with very different connections and functions: the pars compacta (SNpc) and the pars reticulata (SNpr). The pars compacta serves mainly as a projection to the basal ganglia circuit, supplying the striatum with dopamine. The pars reticulata conveys signals from the basal ganglia to numerous other brain structures. Structure The substantia nigra, along with four other nuclei, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Colliculus
In neuroanatomy, the superior colliculus () is a structure lying on the tectum, roof of the mammalian midbrain. In non-mammalian vertebrates, the Homology (biology), homologous structure is known as the optic tectum or optic lobe. The adjective form ''tectum, tectal'' is commonly used for both structures. In mammals, the superior colliculus forms a major component of the midbrain. It is a paired structure and together with the paired inferior colliculi forms the corpora quadrigemina. The superior colliculus is a layered structure, with a pattern that is similar in all mammals. The layers can be grouped into the superficial layers (retinal nerve fiber layer, stratum opticum and above) and the deeper remaining layers. Neurons in the superficial layers receive direct input from the retina and respond almost exclusively to visual stimuli. Many neurons in the deeper layers also respond to other modalities, and some respond to stimuli in multiple modalities. The deeper layers also conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Ganglia
The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into external and internal regions, and in the division of the striatum. Positioned at the base of the forebrain and the top of the midbrain, they have strong connections with the cerebral cortex, thalamus, brainstem and other brain areas. The basal ganglia are associated with a variety of functions, including regulating voluntary motor control, motor movements, procedural memory, procedural learning, habituation, habit formation, conditional learning, eye movements, cognition, and emotion. The main functional components of the basal ganglia include the striatum, consisting of both the dorsal striatum (caudate nucleus and putamen) and the ventral striatum (nucleus accumbens and olfactory tubercle), the globus pallidus, the ventral pallidum, the substa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primate Basal Ganglia System
The basal ganglia form a major brain system in all vertebrates, but in primates (including humans) there are special differentiating features. The basal ganglia include the striatum, globus pallidus, substantia nigra and subthalamic nucleus. In primates the pallidus is divided into an external globus pallidus, external and internal globus pallidus, the external globus pallidus is present in other mammals but not the internal globus pallidus. Also in primates, the dorsal striatum is divided by a large nerve tract called the internal capsule into two masses named the caudate nucleus and the putamen. These differences contribute to a complex circuitry of connections between the striatum and cortex that is specific to primates, reflecting different functions in primate cortical areas. Corticostriatal connection A major output from the cortex, with axons from most of the cortical regions connecting to the striatum, is called the corticostriatal connection, part of the cortico-basal gang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
