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Thalamic Pathway
The thalamus (: thalami; from Greek θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the 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-like exchanges of information. It has several functions, such as the relaying of sensory and 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 are paired structures of gray matter about four centimetres long and ovoid in appearance, located in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as visual perception, vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective segmentation (biology), body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a brain vesicle, vesicular enlargement at the rostral (anatomical term), rostral end of the neural tube, with centralized control over all body segments. All vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consciousness
Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, and theologians. Opinions differ about what exactly needs to be studied or even considered consciousness. In some explanations, it is synonymous with the mind, and at other times, an aspect of it. In the past, it was one's "inner life", the world of introspection, of private thought, imagination, and volition (psychology), volition. Today, it often includes any kind of cognition, experience, feeling, or perception. It may be awareness, awareness of awareness, metacognition, or self-awareness, either continuously changing or not. The disparate range of research, notions, and speculations raises a curiosity about whether the right questions are being asked. Examples of the range of descriptions, definitions or explanations are: ordered distinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Nuclear Group
The lateral nuclear group is a collection of nuclei on the lateral side of the thalamus. This nucleus group is one of the three regions of the thalamus which result from trisection by the Y-shaped internal medullary lamina. The name "lateral nuclear group" is also given to a subset of the lateral group of nuclei which result from trisection by the internal medullary lamina. The lateral nuclear group consists of the following: * lateral dorsal nucleus * lateral posterior nucleus * pulvinar nuclei The lateral region of the thalamus which results from trisection by the internal medullary lamina also includes the ventral nuclear group and the lateral Lateral is a geometric term of location which may also refer to: Biology and healthcare * Lateral (anatomy), a term of location meaning "towards the side" * Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx * Lateral release ( ... and medial geniculate nuclei. References Thalamic nuclei {{Neuroana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenesis
Phylogenesis (from Greek φῦλον ''phylon'' "tribe" + γένεσις ''genesis'' "origin") is the biological process by which a taxon (of any rank) appears. The science that studies these processes is called phylogenetics. These terms may be confused with the term phylogenetics, the application of molecular - analytical methods (i.e. molecular biology and genomics), in the explanation of phylogeny and its research. Phylogenetic relationships are discovered through phylogenetic inference methods that evaluate observed heritable traits, such as DNA sequences or overall morpho-anatomical, ethological, and other characteristics. Phylogeny The result of these analyses is a phylogeny (also known as a phylogenetic tree) – a diagrammatic hypothesis about the history of the evolutionary relationships of a group of organisms. Phylogenetic analyses have become central to understanding biodiversity, evolution, ecological genetics and genomes. Cladistics Cladistics ( Gree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neothalamus
The paleothalamus is an obsolete term for the portion of the thalamus that is believed to be phylogenetically (or evolutionarily) older than other parts of the thalamus. Specifically, the midline and medial nuclei of the thalamus, as well as the intralaminar nucleus, are considered to belong to the paleothalamus The term "paleothalamus" is opposed to the paired term neothalamus (also considered to be obsolete), which designates the phylogenetically (or evolutionarily) newer or younger parts of the thalamus, specifically, lateral nuclei of the thalamus, the pulvinar and the geniculate bodies. Initially, the paleothalamus was distinguished from other parts of the thalamus (i.e. from the neothalamus) on the basis that paleothalamic nuclei were believed to lack reciprocal connections with neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interthalamic Adhesion
The interthalamic adhesion (also known as the massa intermedia, intermediate mass or middle commissure) is a flattened band of tissue that connects both parts of the thalamus at their medial surfaces. The medial surfaces form the upper part of the lateral wall to the third ventricle. In humans, it is only about one centimeter long – though in females, it is about 50% larger on average. Sometimes, it is in two parts – and 20% of the time, it is absent. In other mammals, it is larger. In 1889, a Portuguese anatomist by the name of Macedo examined 215 brains, showing that male humans are approximately twice as likely to lack an interthalamic adhesion as are female humans. He also reported its absence, still reported today in about 20% of humans. Its absence is seen to be of no consequence. The interthalamic adhesion contains nerve cells and nerve fibers; a few of the latter may cross the middle line, but most of them pass toward the middle line and then curve laterally on the ... [...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 sprea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamic Reticular Nucleus
The thalamic reticular nucleus is part of the ventral thalamus that forms a capsule around the thalamus laterally. However, recent evidence from mice and fish question this statement and define it as a dorsal thalamic structure. It is separated from the thalamus by the external medullary lamina. Reticular nucleus cells are all GABAergic, and have discoid dendritic arbors in the plane of the nucleus. Thalamic Reticular Nucleus is variously abbreviated TRN, RTN, NRT, and RT. The TRN is found in all mammals. Input and output The thalamic reticular nucleus receives input from the cerebral cortex and dorsal thalamic nuclei. Most input comes from collaterals of fibers passing through the thalamic reticular nucleus. The outputs from the primary thalamic reticular nucleus project to dorsal thalamic nuclei, but never to the cerebral cortex. This is the only thalamic nucleus that does not project to the cerebral cortex. Instead it modulates the information from other nuclei in the thala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm His Sr
__NOTOC__ Wilhelm His Sr. (9 July 1831 – 1 May 1904) was a Swiss anatomist and professor who invented the microtome. By treating animal tissue with acids and salts to harden it and then slicing it very thinly with the microtome, scientists were able to further study the organization and function of tissues and cells under a microscope. Career His came from a patrician family and studied medicine in Basel, Berlin (under Johannes Peter Müller and Robert Remak), Würzburg (under Rudolf Virchow and Albert von Kölliker), Bern, Vienna and Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci .... He received a doctorate in 1854, and in 1856 received the habilitation (higher doctorate) in Basel. In 1855, he was the first to describe the tubercles in the human foetus which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryologist
Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology. Early embryology was proposed by Marcello Malpighi, and known as preformationism, the theory that organisms develop from pre-existing miniature versions of themselves. Aristotle proposed the theory that is now accepted, epigenesis. Epigenesis is the idea that organisms develop from seed or egg in a sequence of steps. Modern embryology developed from the work of Karl Ernst von Baer, though accurate observations had been made in Italy by anatomists such as Aldrovandi and Leonardo da Vinci in the Renaissance. Comparative embryology Preformationism and epigenesis As recently as the 18th century, the prevailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryonic Development
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm, sperm cell (spermatozoon). Once fertilized, the ovum becomes a single diploid cell known as a zygote. The zygote undergoes mitosis, mitotic cell division, divisions with no significant growth (a process known as cleavage (embryo), cleavage) and cellular differentiation, leading to development of a multicellular embryo after passing through an organizational checkpoint during mid-embryogenesis. In mammals, the term refers chiefly to the early stages of prenatal development, whereas the terms fetus and fetal development describe later stages. The main stages of animal embryonic development are as follows: * The zygote undergoes a series of cell divisions (called cleavage) to form a structure called a morula. * The morula develops into a structure called a bla ... [...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] |
