what are the three types of nervous systems
Neuroanatomy


text Cerebri anatome which is considered the foundation of neuroanatomy. The subsequent three hundred and fifty some years has produced a great deal of documentation and study of the neural systems. At the tissue level, the nervous system is composed of neurons, glial cells, and extracellular matrix. Both neurons and glial cells come in many types (see, for example, the nervous system section of the list of distinct cell types in the adult human body). Neurons are the information-processing cells of the nervous system: they sense
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Functional psychology


and physiologically) difficult to integrate the two concepts without raising further questions about human behaviour. For instance, consider the interrelationship between three elements: the human environment, the human autonomic nervous system (our fight or flight muscle responses), and the human somatic nervous system (our voluntary muscle control). The behaviourist perspective explains a mixture of both types of muscle behaviour, whereas the functionalist perspective resides mostly in the somatic nervous system. It can be argued that all behavioural origins begin within the nervous system, prompting all scientists
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Connective tissue


Connective tissue (CT) is one of the four basic types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesoderm. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. In the central nervous system, the three outer membranes (the meninges) that envelop the brain and spinal cord are composed of connective tissue. They support and protect the body. All connective tissue consists of three main components: fibers (elastic and collagenous
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Dendritic spike


sodium channels have been identified. Voltage-gated sodium channels found in mammals can be divided into three types: Nav1.x, Nav2.x, and Nav3.x. Nav1.x sodium channels are associated with the central nervous system. Nav1.1, Nav2.2, and Nav1.6 are three isoforms of the voltage-gated sodium channels that are present at high levels in the central nervous system of an adult rat brain. These channels have been well documented in the axonal membrane of the central nervous system. Nav1.2 has been primarily identified in unmyelinated axons while high concentrations of
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Nerve tract


A nerve tract is a bundle of nerve fibers (axons) connecting nuclei of the central nervous system. In the peripheral nervous system this is known as a nerve, and has associated connective tissue. The main nerve tracts in the central nervous system are of three types: association fibers, commissural fibers, and projection fibers. A tract may also be referred to as a commissure, fasciculus or decussation. A commissure connects the two cerebral hemispheres at the same levels. Examples are the posterior commissure and the corpus callosum. A
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Pavlov's typology


Pavlov into strong and weak nervous systems with different sub-types under the strong type. These different types of systems were categorized based on the strength of excitation or inhibition in the system of the observed individual. Those individuals with weak nervous systems were thought by Pavlov "to have limited adaptive abilities," while strong nervous systems were more adaptable. Although Pavlov's typology originated as a purely conceptual idea, modern technology has helped research in the area to provide evidence for the processes of higher nervous activity that Pavlov hypothesized. Despite
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Central nervous system cyst


A central nervous system cyst is a type of cyst that presents and affects part of the central nervous system (CNS). They are usually benign and filled with either cerebrospinal fluid, blood, or tumor cells. CNS cysts are classified into two categories: cysts that originate from non-central nervous system tissue, migrate to, and form on a portion of the CNS, and cysts that originate within central nervous system tissue itself. Within these two categories, there are many types of CNS cysts that have been identified from
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Nervous system


isolated cells. In bilaterian animals, which make up the great majority of existing species, the nervous system has a common structure that originated early in the Ediacaran period, over 550 million years ago. The nervous system contains two main categories or types of cells: neurons and glial cells. The nervous system is defined by the presence of a special type of cell—the neuron (sometimes called "neurone" or "nerve cell"). Neurons can be distinguished from other cells in a number of ways, but their
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Enteric nervous system


The enteric nervous system (ENS) or intrinsic nervous system is one of the main divisions of the autonomic nervous system (ANS) and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the sympathetic and parasympathetic nervous systems, although it may be influenced by them. The ENS is also called the second brain. It is derived from neural crest cells. The enteric nervous system in humans consists of some 500 million neurons (including the various types
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T-type calcium channel


are generally located within the brain, peripheral nervous system, heart, smooth muscle, bone, and endocrine system. The distinct structures of T-type calcium channels are what allow them to conduct in these manners, consisting of a primary α subunit. The α subunit of T-type channels is the primary subunit that forms the pore of the channel, and allows for entry of calcium. T-type calcium channels function to control the pace-making activity of the SA Node within the heart and relay rapid action potentials
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Neuropharmacology


were able to figure out a basic understanding of the nervous system and how nerves communicate between one another. Before this discovery, there were drugs that had been found that demonstrated some type of influence on the nervous system. In the 1930s, French scientists began working with a compound called phenothiazine in the hope of synthesizing a drug that would be able to combat malaria. Though this drug showed very little hope in the use against malaria-infected individuals, it was found to have sedative effects along with what appeared to be beneficial
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Neuromechanics


The nervous system is divided into two sub-systems: the peripheral nervous system and the central nervous system. The peripheral nervous system is then composed of three sub-systems: the somatic nervous system, the autonomic nervous system, and the visceral nervous system. The autonomic nervous system is also broken down into the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system. The nervous system responsible for voluntary motion, including lower limb motion, is the somatic nervous system. Though the somatic nervous system is
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Acetylcholine


, polymyxin) 2) Magnesium:  antagonizes P-type calcium channels 3) Hypocalcemia 4) Anticonvulsants 5) Diuretics (furosemide) 6) Eaton-Lambert syndrome:  inhibits P-type calcium channels 7) Botulinum toxin:  inhibits SNARE proteins Calcium channel blockers (nifedipine, diltiazem) do not affect P-channels.  These drugs affect L-type calcium channels. The autonomic nervous system controls a wide range of involuntary and unconscious body functions. Its main branches are the sympathetic nervous system and parasympathetic nervous system. Broadly speaking
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Neuroregeneration


the environment. It is important to note that central nervous system axons have been proven to regrow in permissive environments; therefore, the primary problem to central nervous system axonal regeneration is crossing or eliminating the inhibitory lesion site. Another problem is that the morphology and functional properties of central nervous system neurons are highly complex, for this reason a neuron functionally identical cannot be replaced by one of another type (Llinás' law). Glial cell scar formation is induced following damage to the nervous system. In the central nervous system
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HSN2


Hereditary sensory neuropathy, type II also known as HSN2 is a protein which in humans in encoded by the "HSN2". It is a single-exon ORF, and a nervous system-specific exon of the WNK1 gene. HSN2 is as an alternatively spliced exon of WNK1 and this selectively occurs in nervous tissues, resulting in WNK1/HSN2 nervous system isoforms. The WNK1/HSN2 isoforms are expressed in the sensory parts of the peripheral nervous system and central nervous system which are associated with the transmission of sensory and nociceptive
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Vomiting


and as such lies outside the blood–brain barrier; it can therefore be stimulated by blood-borne drugs that can stimulate vomiting or inhibit it. There are various sources of input to the vomiting center: The vomiting act encompasses three types of outputs initiated by the chemoreceptor trigger zone: Motor, parasympathetic nervous system (PNS), and sympathetic nervous system (SNS). They are as follows: The neurotransmitters that regulate vomiting are poorly understood, but inhibitors of dopamine, histamine, and serotonin are all used to suppress
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Pavlov's typology


. Inhibition, on the other hand, is when a response that is already encoded is overcome or contained. Mobility is the ability of the nervous system to give one impulse priority over another. This can be done by having excitation before inhibition, or vice versa. Pavlov looked at the balance between excitation and inhibition and determined that there were different types of nervous systems. These observations were made about dogs, but Pavlov believed that they could be generalized to humans as well. The different types of nervous systems were categorized by
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Samael Aun Weor


extensive methods of meditation, self-observation, and sexual transmutation are taught and prescribed for daily exercise. The goal of psychological work is the awakening of consciousness and ultimately the state of Paramarthasatya. Basic physiology is studied, mostly endocrinology and the hormonal influence of primary and secondary sexual characteristics. It is taught that there are three fundamental nervous systems, the cerebrospinal nervous system, grand sympathetic nervous system, and the Parasympathetic nervous system. These nervous systems are referred to as the "Three Brains" or three centers of the intellectual
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Neurogenomics


Neurogenomics is the study of how the genome of an organism influences the development and function of its nervous system. This field intends to unite functional genomics and neurobiology in order to understand the nervous system as a whole from a genomic perspective. The nervous system in vertebrates is made up of two major types of cells – neuroglial cells and neurons. Hundreds of different types of neurons exist in humans, with varying functions – some of them process external stimuli; others generate a response to stimuli; others organize in centralized structures (brain
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Parasympathetic nervous system


types of muscarinic receptors: In vertebrates, nicotinic receptors are broadly classified into two subtypes based on their primary sites of expression: muscle-type nicotinic receptors (N1) primarily for somatic motor neurons; and neuronal-type nicotinic receptors (N2) primarily for autonomic nervous system. Sympathetic and parasympathetic divisions typically function in opposition to each other. The sympathetic division typically functions in actions requiring quick responses. The parasympathetic division functions with actions that do not require immediate reaction. A useful mnemonic to summarize the functions of the parasympathetic nervous
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Muscle tissue


involuntarily, without conscious intervention. These muscle types may be activated both through interaction of the central nervous system as well as by receiving innervation from peripheral plexus or endocrine (hormonal) activation. Striated or skeletal muscle only contracts voluntarily, upon influence of the central nervous system. Reflexes are a form of nonconscious activation of skeletal muscles, but nonetheless arise through activation of the central nervous system, albeit not engaging cortical structures until after the contraction has occurred. The different muscle types vary in their response to neurotransmitters and endocrine substances such
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Sensory nervous system


where it is processed and interpreted. Chemoreceptors, or chemosensors, detect certain chemical stimuli and transduce that signal into an electrical action potential. The two primary types of chemoreceptors are: Photoreceptors are capable of phototransduction, a process which converts light (electromagnetic radiation) into, among other types of energy, a membrane potential. The three primary types of photoreceptors are: Cones are photoreceptors which respond significantly to color. In humans the three different types of cones correspond with a primary response to short wavelength (blue), medium wavelength
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Neuroanatomy


system, or PNS). The delineation of distinct structures and regions of the nervous system has been critical in investigating how it works. For example, much of what neuroscientists have learned comes from observing how damage or "lesions" to specific brain areas affects behavior or other neural functions. For information about the composition of non-human animal nervous systems, see nervous system. For information about the typical structure of the Homo sapiens nervous system, see human brain or peripheral nervous system. This article discusses information pertinent to the
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Center for Applied Genomics


of cancers and has had a major impact on our understanding of how cancer occurs. Neuroblastoma is a type of cancer most commonly found in children that affects the sympathetic nervous system (part of the nervous system that helps control our organs). It is often lethal. In 2008, the Center group collaborated with the Maris Lab at the Children's Hospital of Pennsylvania to publish the first of three important papers on the genetic causes of neuroblastoma. They performed a genome-wide association study comparing the genomes of 1032 patients and 2043
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Nerve injury


Nerve injury is injury to nervous tissue. There is no single classification system that can describe all the many variations of nerve injury. In 1941, Seddon introduced a classification of nerve injuries based on three main types of nerve fiber injury and whether there is continuity of the nerve. Usually, however, (peripheral) nerve injury is classified in five stages, based on the extent of damage to both the nerve and the surrounding connective tissue, since supporting glial cells may be involved. Unlike in the central nervous system, neuroregeneration
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N-type calcium channel


nervous system, but they are also involved with the function of the heart and kidneys. They are important in neurotransmitter release because they are localized at the synaptic terminals. In the peripheral nervous system, N-type channels are known to be involved in the release of many neurotransmitters like glutamate, GABA, acetylcholine, dopamine, and norepinephrine. When extracellular calcium flows into N-type calcium channels due to an action potential, it triggers the fusion of the secretory vesicles. Studies on the cardiovascular system reveal when ω-Conotoxin
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Ganglionic blocker


A ganglionic blocker (or ganglioplegic) is a type of medication that inhibits transmission between preganglionic and postganglionic neurons in the Autonomic Nervous System, often by acting as a nicotinic receptor antagonist. Nicotinic acetylcholine receptors are found on skeletal muscle, but also within the route of transmission for the parasympathetic and sympathetic nervous system (which together comprise the autonomic nervous system). More specifically, nicotinic receptors are found within the ganglia of the autonomic nervous system, allowing outgoing signals to be transmitted from the presynaptic to the postsynaptic cells. Thus,
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Nervous system network models


operation system and try to simulate its functionalities. In order to accomplish this, one needs to model its components and functions and validate its performance with real life. Computational models of a well simulated nervous system enable learning the nervous system and apply it to real life problem solutions. What is brain and what is neural network? Section 2.1 addresses the former question from an evolutionary perspective. The answer to the second question is based on the neural doctrine proposed by Ramon y Cajal (1894). He hypothesized that the elementary biological
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Canine brain tumors


Cancer of the nervous system is common in domestic canids, and includes primary neoplasia of the peripheral nervous system, primary neoplasia of the central nervous system and various metastatic cancers. Some of the most common of the central nervous system tumors are several types of primary (originating from brain tissue) canine brain tumors. Examples of these include: meningiomas, astrocytomas, glioblastomas, oligodendriomas, choroid plexus papillomas, and pituitary adenomas. Breeds predisposed to brain tumors include: Boxer Dog, Pug, English Bull Dog, Boston Terrier, and
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EMA401


have major molecular and mechanistic differences compared to pain pathways of the peripheral nervous system. EMA401 target proteins, angiotensin II type 2 receptors, are extremely important for nociception within the peripheral nervous system and less so for nociception within other functional systems. EMA401 is the first drug on the market that targets angiotensin II type 2 receptors (ATR) with high affinity but has a low affinity for angiotensin II type 1 receptors. Angiotensin II receptor antagonists that have existed in the pharmaceutical market have had higher affinities for angiotensin II type 1 receptors
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Neurofibromatosis


Neurofibromatosis (NF) is a group of three conditions in which tumors grow in the nervous system. The three types are neurofibromatosis type I (NF1), neurofibromatosis type II (NF2), and schwannomatosis. In NF1 symptoms include light brown spots on the skin, freckles in the armpit and groin, small bumps within nerves, and scoliosis. In NF2 there may be hearing loss, cataracts at a young age, balance problems, flesh colored skin flaps, and muscle wasting. The tumors are generally non-cancerous.
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Stimulus filtering


amplifying vibrational energy between the membranes. After sound hits the membranes at different amplitudes, the presternum sets up symmetrical vibration modes through bending and rocking. This effect helps the nervous system distinguish which side the sound is coming from. Because the presternum acts as an intertympanal bridge, the ITD is increased from 1.5 us to 55 us and the ILD is increased from less than one decibel to over 10 decibels. When looking at the nervous systems of flies, researchers found three auditory afferents. Type one fires only one spike to the
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WHO classification of tumours of the central nervous system


adjacent tissues. Most common primary tumour site Reference : WHO pathology of tumours of central nervous system-2007 Kleihues P, Burger PC, Scheithauer BW (eds) (1993) Histological typing of tumours of the central nervous system. World Health Organization international histological classification of tumours. Springer, Heidelberg Kleihues P, Cavenee WK (eds) (2000) World Health Organization Classification of Tumours. Pathology and genetics of tumours of the nervous system. IARC Press This is the classification used until 2015. This version covered many techniques to diagnose the
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Programmed cell death


or chemical abuse or lysis of the cell are considered not to be atrophic factors. Common types of atrophic factors are: The initial expansion of the developing nervous system is counterbalanced by the removal of neurons and their processes. During the development of the nervous system almost 50% of developing neurons are naturally removed by programmed cell death (PCD). PCD in the nervous system was first recognized in 1896 by John Beard. Since then several theories were proposed to understand its biological significance during neural development. PCD in the developing nervous
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Enteric nervous system


of Dogiel cells), 0.5% of the number of neurons in the brain, five times as many as the one hundred million neurons in the human spinal cord, and about 2/3 as many as in the whole nervous system of a cat. The enteric nervous system is embedded in the lining of the gastrointestinal system, beginning in the esophagus and extending down to the anus. The neurons of the ENS are collected into two types of ganglia: myenteric (Auerbach's) and submucosal (Meissner's) plexuses. Myenteric plexuses
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Psychological resilience


"protective factors". These factors are likely to play a more important role, the greater the individual's exposure to cumulative risk factors. Three notable bases for resilience—self-confidence, self-esteem and self-concept—all have roots in three different nervous systems—respectively, the somatic nervous system, the autonomic nervous system and the central nervous system. An emerging field in the study of resilience is the neurobiological basis of resilience to stress. For example, neuropeptide Y (NPY) and 5-Dehydroepiandrosterone (5-DHEA
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Nervous system


, rapid coordination of organ systems, and integrated processing of concurrent signals. In humans, the sophistication of the nervous system makes it possible to have language, abstract representation of concepts, transmission of culture, and many other features of human society that would not exist without the human brain. Most neurons send signals via their axons, although some types are capable of dendrite-to-dendrite communication. (In fact, the types of neurons called amacrine cells have no axons, and communicate only via their dendrites.) Neural
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N-type calcium channel


-type Calcium channels serve to regulate pain signals sent from the peripheral nervous system to Central Nervous System. There are many known blockers that function very similarly to one another, but the most common are the conotoxins. To block a voltage-gated channel, the voltage current that activates the channels needs to be stopped. These toxins and blockers generally function by modulating G-Protein Coupled Receptors (GPCR) that mediate the N-type Calcium channels. This modulation of GPCRs activates GABA, an inhibitory neurotransmitter. This GABA results
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Muscular system


The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture and circulates blood throughout the body. The muscular systems in vertebrates are controlled through the nervous system although some muscles (such as the cardiac muscle) can be completely autonomous. Together with the skeletal system, it forms the musculoskeletal system, which is responsible for movement of the human body. There are three distinct types of muscles: skeletal muscles, cardiac or heart muscles, and smooth (non
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Depressant


what central nervous system depressants do. Contrary to popular misconception, opioids are not depressants in the classical sense. They do produce central nervous system depression, however, they also excite certain areas of the central nervous system. To remain true to the term 'depressant' – opioids cannot be classified as such. For opioid agonists and opium derivatives, these are classified differently. Analgesic or narcotic correctly identifies these drugs. However, they do have depressant actions nonetheless. Combining multiple depressants can be very dangerous because the central nervous
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Biological neuron model


A biological neuron model, also known as a spiking neuron model, is a mathematical description of the properties of certain cells in the nervous system that generate sharp electrical potentials across their cell membrane, roughly one millisecond in duration, as shown in Fig. 1. Spiking neurons are known to be a major signaling unit of the nervous system, and for this reason characterizing their operation is of great importance. It is worth noting that not all the cells of the nervous system produce the type of spike that define the scope of
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Paruresis


Paruresis ( ) is a type of phobia in which the sufferer is unable to urinate in the real or imaginary presence of others, such as in a public restroom. The analogous condition that affects bowel movement is called parcopresis or shy bowel. It appears that paruresis involves a tightening of the sphincter and/or bladder neck due to a sympathetic nervous system response. The adrenaline rush that produces the involuntary nervous system response probably has peripheral and central nervous system involvement. The internal urethral sphincter (smooth muscle tissue) or the external urethral sphincter
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Acetylcholine


phospholipase C. Their effect on target cells is usually excitatory. The M2 and M4 subtypes are G/G-coupled; they decrease intracellular levels of cAMP by inhibiting adenylate cyclase. Their effect on target cells is usually inhibitory. Muscarinic acetylcholine receptors are found in both the central nervous system and the peripheral nervous system of the heart, lungs, upper gastrointestinal tract, and sweat glands. Acetylcholine is the substance the nervous system uses to activate skeletal muscles, a kind of striated muscle. These are the muscles used for all types
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Neural plate


is completed when the neural folds are brought together, adhering to each other. While the cells that remain as the neural tube form the brain and spinal cord, the other cells that were part of the neural plate migrate away from the tube as neural crest cells. After an epithelial–mesenchymal transition, these cells form the autonomic nervous system and certain cells of the peripheral nervous system. Critical to the proper folding and function of the neural plate is N-cadherin, a type of cadherin protein associated with the nervous system
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Orbital lymphoma


of ocular lymphomas: intraocular lymphomas and adnexal lymphomas. An intraocular lymphoma occurs within the eye, while an adnexal lymphoma occurs outside, but adjoined to the eye. There are two main types of intraocular lymphomas: primary central nervous system involvement (PCNSL) and primary central nervous system with ocular involvement (PCNSLO). The difference between PCNSL and PCNSLO is that PNSCL involves the central nervous system, while PCNSLO does not. 56-86% of orbital lymphomas are classified PCNSL and 15-25% are classified PCNSLO. PCNSLO
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Muscarinic acetylcholine receptor


. The sympathetic nervous system also has some preganglionic nerves terminating at the chromaffin cells in the adrenal medulla, which secrete epinephrine and norepinephrine into the bloodstream. Some believe that chromaffin cells are modified postganglionic CNS fibers. In the adrenal medulla, acetylcholine is used as a neurotransmitter, and the receptor is of the "nicotinic" type. The somatic nervous system uses a nicotinic receptor to acetylcholine at the neuromuscular junction. Muscarinic acetylcholine receptors are also present and distributed throughout the local nervous system, in post-synaptic and pre-synaptic
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Italian crested newt


be achieved by the autonomous nervous control system. More developmental changes include humoral and nervous control mechanisms, which will actually combine so that response to physiological and environmental changes will be met with a more coordinated reaction. The nervous system assists in development of cardiovascular functions, but this change will occur much later in life. Any time there is a switch from one type of respiration (e.g. cutaneous) to another (e.g. lung) there will be a required alteration and modification of the circulatory system. Another increase that comes with development
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Nervous system


of the radially symmetric organisms ctenophores (comb jellies) and cnidarians (which include anemones, hydras, corals and jellyfish) consist of a diffuse nerve net. All other animal species, with the exception of a few types of worm, have a nervous system containing a brain, a central cord (or two cords running in parallel), and nerves radiating from the brain and central cord. The size of the nervous system ranges from a few hundred cells in the simplest worms, to around 300 billion cells in African elephants
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Epigenetics of neurodegenerative diseases


Neurodegenerative diseases are a heterogenous group of complex disorders linked by the degeneration of neurons in either the peripheral nervous system or the central nervous system. Their underlying causes are extremely variable and complicated by various genetic and/or environmental factors. These diseases cause progressive deterioration of the neuron resulting in decreased signal transduction and in some cases even neuronal death. Peripheral nervous system (PNS) diseases may be further categorized by the type of nerve cell (motor, sensory, or both) affected by the disorder. Effective treatment of these diseases is often
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Sensory nerve


A sensory nerve, also called an afferent nerve, is a nerve that carries sensory information toward the central nervous system (CNS). It is a cable-like bundle of the afferent nerve fibers coming from sensory receptors in the peripheral nervous system (PNS). A motor nerve carries information from the CNS to the PNS, and both types of nerve are called peripheral nerves. Afferent nerve fibers link the sensory neurons throughout the body, in pathways to the relevant processing circuits in the central nervous system. Afferent nerve fibers
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Chengjiangocaris


study." The 520 million-year-old fossilized nervous system is the most complete example of its type and could help unravel how the nervous system evolved in early animals. The fossil was excavated in southern China. Individual nerves are visible. Fossilized soft tissue is rare, but this particular find, by researchers in the UK, China and Germany, represents the most detailed example of a preserved nervous system yet discovered. "Chengjiangocaris kunmingensis" lived during the Cambrian explosion, a period of rapid evolutionary development about half a
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Andrea Brand


in a self-renewing manner, generating daughter cells that give rise to different types of neurons. The aim of our work is to identify the genes that direct the different behaviours of cells in the developing nervous system. When we identify the genes that specify the characteristic behaviours of each of the different cell types in the nervous system, it may become possible to manipulate them in such a way as to induce stem cells to become neurons at will, or induce neurons to regenerate.” “In earlier work,” the
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Pavlov's typology


the dogs through his research on salivary responses. He noticed there were weak and strong dogs. These groups were later divided into equilibrated and non-equilibrated, and then subdivided again into mobile and inert. Pavlov defined types of animal nervous system in one of two ways: either in “terms of specific complexes of the properties of the nervous processes, characteristic for the given animal, or in terms of patterns of animal or human behavior.” Pavlov proposed his classification of types on the differences in the properties of the nervous
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Nervous system network models


. There are three types of brain connectivity models of a network (Sporns, O. (2007)). “Anatomical (or structural) connectivity” describes a network with anatomical links having specified relationship between connected “units.” If the dependent properties are stochastic, it is defined as “functional connectivity.” “Effective connectivity” has causal interactions between distinct units in the system. As stated earlier, brain connectivity can be described at three levels. At microlevel, it connects neurons through electrical or chemical synapses. A
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Cannabinoid receptor type 1


Cannabinoid receptor type 1 (CB), also known as cannabinoid receptor 1, is a G protein-coupled cannabinoid receptor that in humans is encoded by the "CNR1" gene. The human CB receptor is expressed in the peripheral nervous system and central nervous system. It is activated by: endocannabinoids, a group of retrograde neurotransmitters that include anandamide and 2-arachidonoylglycerol (2-AG); plant phytocannabinoids, such as the compound THC which is an active ingredient of the psychoactive drug cannabis; and, synthetic analogs of THC. CB1 is
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Adrenergic nerve fibre


are call the node of ranvier. There are several types of adrenergic receptors which are identified by their differing sensitivities to various drugs. Neurons in the central nervous system contain α1- and α2-adrenergic receptors and β1- and β2-adrenergic receptors. All four kinds of receptors are also found in the various organs of the body aside from the brain. They are responsible for the effects of epinephrine and norepinephrine when they act as hormones outside the central nervous system. In the brain, all autoreceptors appear to be of the α2 type. (The drug
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Motor control


percentage of Type II fibers gives a person more potential of quicker movement, there is little doubt that the nervous system and the brain is more important on affecting the performance. Most of the time, the real limit to athletes' performance is the number of motor units their nervous systems can recruit in the short period of time and the amount of forces (size of the muscle fibers) provided of those motor units. The performance is rarely affected by the type of muscle fiber (slow twitch or fast) that constructed to
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Dopamine


presence of dopamine, with no indication of its function; however, dopamine has been reported in the nervous systems of many other radially symmetric species, including the cnidarian jellyfish, hydra and some corals. This dates the emergence of dopamine as a neurotransmitter back to the earliest appearance of the nervous system, over 500 million years ago in the Cambrian Period. Dopamine functions as a neurotransmitter in vertebrates, echinoderms, arthropods, molluscs, and several types of worm. In every type of animal that has been examined, dopamine has been
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Peripheral nerve interface


study the form and function of the peripheral nervous system. Many researchers also focus in the area of neuroprosthesis, linking the human nervous system to bionics in order to mimic natural sensorimotor control and function. Successful implantation of peripheral nerve interfaces depend on a number of factors which include appropriate indication, perioperative testing, differentiated planning, and functional training. Typically microelectrode devices are implanted adjacent to, around or within the nerve trunk to establish contact with the peripheral nervous system. Different approaches may be used depending on the type of signal desired
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Evolution of nervous systems


the sensory neurons and send signals to groups of motor neurons as a result. In some cases groups of intermediate neurons are clustered into discrete ganglia. The development of the nervous system in radiata is relatively unstructured. Unlike bilaterians, radiata only have two primordial cell layers, endoderm and ectoderm. Neurons are generated from a special set of ectodermal precursor cells, which also serve as precursors for every other ectodermal cell type. Neural induction represents the initial step in the generation of the nervous system and begins with the segregation of neural and
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Alfred Korzybski


in what they know by (1) the structure of their nervous systems, and (2) the structure of their languages. Humans cannot experience the world directly, but only through their "abstractions" (nonverbal impressions or "gleanings" derived from the nervous system, and verbal indicators expressed and derived from language). These sometimes mislead us about what is the truth. Our understanding sometimes lacks "similarity of structure" with what is actually happening. He sought to train our awareness of abstracting, using techniques he
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Ganglion


form a complex system of ganglia known as a plexus. Ganglia provide relay points and intermediary connections between different neurological structures in the body, such as the peripheral and central nervous systems. Among vertebrates there are three major groups of ganglia: In the autonomic nervous system, fibers from the central nervous system to the ganglia are known as preganglionic fibers, while those from the ganglia to the effector organ are called postganglionic fibers. The term "ganglion" refers to the peripheral nervous system. However, in the brain (part of
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Parasympathetic nervous system


nerve. Three spinal nerves in the sacrum (S2-4), commonly referred to as the pelvic splanchnic nerves, also act as parasympathetic nerves. Owing to its location, the parasympathetic system is commonly referred to as having "craniosacral outflow", which stands in contrast to the sympathetic nervous system, which is said to have "thoracolumbar outflow". The parasympathetic nerves are autonomic or "visceral" branches of the peripheral nervous system (PNS). Parasympathetic nerve supply arises through three primary areas: As in the sympathetic
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Vascular smooth muscle


Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. Vascular smooth muscle is innervated primarily by the sympathetic nervous system through adrenergic receptors (adrenoceptors). The three types of adrenoceptors present are: formula_1, formula_2 and formula_3. The main endogenous agonist of these cell receptors is norepinephrine (NE). The adrenergic receptors exert
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Ataxia


and unilateral cases is associated with prominent vertigo, nausea and vomiting. In slow-onset, chronic bilateral cases of vestibular dysfunction, these characteristic manifestations may be absent, and dysequilibrium may be the sole presentation. The three types of ataxia have overlapping causes, and therefore can either coexist or occur in isolation. Cerebellar ataxia can have many causes despite normal neuroimaging. Any type of focal lesion of the central nervous system (such as stroke, brain tumor, multiple sclerosis) will cause the type of ataxia corresponding to the site
440356
Lissencephaly


then extend along the radial glia to reach the cortical zone. It is the disruption of the radial and tangential migration that causes reduced or absence gyri that is known as lissencephaly. The lack of gyri causing a smooth appearance of the cerebral cortex is due to abnormal neuronal migration in the developmental stages of the nervous system. The cause of lissencephaly has been linked to both genetic and non-genetic factors. Three main types of lissencephaly have been identified and although all types display the similar symptoms the pathogenesis of each type varies.
8095981
Central nervous system primitive neuroectodermal tumor


A central nervous system primitive neuroectodermal tumor, often abbreviated as PNET, supratentorial PNET, or CNS-PNET, is one of the 3 types of embryonal central nervous system tumors defined by the World Health Organization (medulloblastoma, atypical teratoid rhabdoid tumor, and PNET). It is considered an embryonal tumor because it arises from cells partially differentiated or still undifferentiated from birth. Those cells are usually neuroepithelial cells, stem cells destined to turn into glia or neurons. It can occur anywhere within the spinal cord and cerebrum and can have
4165480
Neurogenic bowel dysfunction


people with diabetes mellitus experience faecal incontinence due to irreversible autonomic neuropathy this is due to the high blood glucose levels over time damaging the nerves, which can lead to impaired rectal sensation. There are different types of neurons involved in innervating the lower GI tract these include: the enteric nervous system; located within the wall of the gut, and the extrinsic nervous system; comprising sympathetic and parasympathetic innervation. The enteric nervous system directly controls the gut motility, whereas, the extrinsic nerve pathways influence gut contractility indirectly through modifying this enteric
6914660
Paroxysmal kinesigenic choreoathetosis


types of paroxysmal dyskinesias, and occurs more often in males than females. There are two types of PKD, primary and secondary. Primary PKD can be further broken down into familial and sporadic. Familial PKD, which means the individual has a family history of the disorder, is more common, but sporadic cases are also seen. Secondary PKD can be caused by many other medical conditions such as multiple sclerosis (MS), stroke, pseudohypoparathyroidism, hypocalcemia, hypoglycemia, hyperglycemia, central nervous system trauma, or peripheral nervous system
15507638
Effects of alcohol on memory


Ethanol is the type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid that acts as a central nervous system depressant. Ethanol can impair different types of memory. Alcohol acts as a general central nervous system depressant, but it also affects some specific areas of the brain to a greater extent than others. Memory impairment caused by alcohol has been linked to the disruption of hippocampal function — particularly affecting gamma-Aminobutyric acid (GABA) and N-methyl-D-aspartate (NMDA) neurotransmission
19992316
Nervous system


most fundamental property is that they communicate with other cells via synapses, which are membrane-to-membrane junctions containing molecular machinery that allows rapid transmission of signals, either electrical or chemical. Many types of neuron possess an axon, a protoplasmic protrusion that can extend to distant parts of the body and make thousands of synaptic contacts; axons typically extend throughout the body in bundles called nerves. Even in the nervous system of a single species such as humans, hundreds of different types of neurons exist, with a wide variety of
2090366
Hyperoxia


, and oxygen poisoning. There are two main types of oxygen toxicity: central nervous system toxicity (CNS), and pulmonary and ocular toxicity. Temporary exposure to high partial pressures of oxygen at greater than atmospheric pressure can lead to central nervous system toxicity (CNS). An early but serious sign of CNS oxygen toxicity is a grand-mal seizure, also known as a generalized tonic-clonic seizure. This type of seizure consists of a loss of consciousness and violent muscle contractions. Signs and symptoms of oxygen toxicity are
2603376
Neurosarcoidosis


Neurosarcoidosis (sometimes shortened to neurosarcoid) refers to a type of sarcoidosis, a condition of unknown cause featuring granulomas in various tissues, in this type involving the central nervous system (brain and spinal cord). Neurosarcoidosis can have many manifestations, but abnormalities of the cranial nerves (a group of twelve nerves supplying the head and neck area) are the most common. It may develop acutely, subacutely, and chronically. Approximately 5–10 percent of people with sarcoidosis of other organs (e.g. lung) develop central nervous system involvement.
4354588
Nervous system network models


metatheory from which specific models can be generated for specific applications. PDP approach (Rumelhart, J. L., McClelland, J. L., and PDP Research Group (1986)) is a distributed parallel processing of many inter-related operations, somewhat similar to what’s happening in the human nervous system. The individual entities are defined as units and the units are connected to form a network. Thus, in the application to nervous system, one representation could be such that the units are the neurons and the links are the synapses
7513644
Spinothalamic tract


cortex, the primary somatosensory cortex, and insular cortex respectively. The types of sensory information means that the sensation is accompanied by a compulsion to act. For instance, an itch is accompanied by a need to scratch, and a painful stimulus makes us want to withdraw from the pain. There are two sub-systems identified: In the nervous system, the anterolateral system is an ascending pathway that conveys pain, temperature (protopathic sensation), and crude touch from the periphery to the brain. It comprises three main pathways
19458032
Nerve tissue protein


Nerve tissue is a biological molecule related to the function and maintenance of normal nervous tissue. An example would include, for example, the generation of myelin which insulates and protects nerves. These are typically calcium-binding proteins. There are two types of myelin. The first is ogliodendrocyte, which can be found in the mammalian Central Nervous System (CNS). The second is Schwann cells, which are found in the Peripheral Nervous System (PNS). Myelination of axons by these Schwann cells are essential for normal nerve function
19836629
Albert Paul Weiss


a vocal response is produced. The system of vocal responses is what makes language according to Weiss. Language acts as a way for people to relay their nervous system responses to each other. For Weiss, it is impossible to study behavior without language because they interconnected. Language lends to characteristics and interactions that are a reflection of what is happening in one’s nervous system. Since Weiss was a materialist, he wanted to prove that language, a non-tactile thing, does have material origins. Weiss started his behavioral studies
4888359
Earthworm


is surrounded in each segment by a pair of pallial blood vessels that connect the dorsal to the subneural blood vessels. Many earthworms can eject coelomic fluid through pores in the back in response to stress; Australian "Didymogaster sylvaticus" (known as the "blue squirter earthworm") can squirt fluid as high as . The nervous system of an earthworm is segmented and comprises three parts: the central nervous system (CNS), peripheral nervous system and the sympathetic nervous system. The CNS consists of a bilobed brain (cerebral ganglia
15603693
Peripheral nervous system


this plexus is usually divided into three parts: The autonomic nervous system (ANS) controls involuntary responses to regulate physiological functions. The brain and spinal cord of the central nervous system are connected with organs that have smooth muscle, such as the heart, bladder, and other cardiac, exocrine, and endocrine related organs, by ganglionic neurons. The most notable physiological effects from autonomic activity are pupil constriction and dilation, and salivation of saliva. The autonomic nervous system is always activated, but is either in the sympathetic or parasympathetic
5198036
Peripherin


Peripherin is a type III intermediate filament protein expressed mainly in neurons of the peripheral nervous system. It is also found in neurons of the central nervous system that have projections toward peripheral structures, such as spinal motor neurons. Its size, structure, and sequence/location of protein motifs is similar to other type III intermediate filament proteins such as desmin, vimentin and glial fibrillary acidic protein. Like these proteins, peripherin can self-assemble to form homopolymeric filamentous networks (networks formed from peripherin protein dimers), but it can
10734113
Neurological disorder


Neurological disorders can be categorized according to the primary location affected, the primary type of dysfunction involved, or the primary type of cause. The broadest division is between central nervous system disorders and peripheral nervous system disorders. The Merck Manual lists brain, spinal cord and nerve disorders in the following overlapping categories: Many of the diseases and disorders listed above have neurosurgical treatments available (e.g. Tourette's Syndrome, Parkinson's disease, Essential tremor and Obsessive compulsive disorder). Neurological disorders in non-human animals are treated by veterinarians.
13563981
Nervous system


of producing regular sequences of action potentials, or sequences of bursts, even in complete isolation. When intrinsically active neurons are connected to each other in complex circuits, the possibilities for generating intricate temporal patterns become far more extensive. A modern conception views the function of the nervous system partly in terms of stimulus-response chains, and partly in terms of intrinsically generated activity patterns—both types of activity interact with each other to generate the full repertoire of behavior. The simplest type of neural circuit is a reflex arc, which
2090408
Neuroregeneration


that has been shown to inhibit neurite outgrowth extension. This scar formation involves several cell types and families of molecules. In response to scar-inducing factors, astrocytes up regulate the production of chondroitin sulfate proteoglycans. Astrocytes are a predominant type of glial cell in the central nervous system that provide many functions including damage mitigation, repair, and glial scar formation. The RhoA pathway is involved. Chondroitin sulfate proteoglycans (CSPGs) have been shown to be up regulated in the central nervous system (CNS) following injury. Repeating disaccharides
20921056
Sensory-motor coupling


new sensory state will be after the motor command has been completed. The efference copy can be used by the nervous system to distinguish self-generated environmental changes, compare an expected response to what actually occurs in the environment, and to increase the rate at which a command can be issued by predicting an organism's state prior to receiving sensory input. An internal model is a theoretical model used by a nervous system to predict the environmental changes that result from a motor action. The assumption is that the nervous system has an
4721292
Albert Paul Weiss


by examining the human bodies and embryos. Before him, no other researcher questioned what was parts of the nervous system were inherited and which (if any) were developed later on. He examined the anatomical central nervous system of various embryos to compare to human ones. He found that all human infants are born with the same sensori-motor pathways that make up the nervous system. However, the pathways that do not deal with mental functioning such as breathing or digestion mature later on. Weiss also compared the anatomical structures of
4888360
Nervous tissue


and neuroglial cells. Four types of neuroglia found in the CNS are astrocytes, microglial cells, ependymal cells and oligodendrocytes. Two types of neuroglia found in the PNS are satellite cells and Schwann cells. In the central nervous system (CNS), the tissue types found are grey matter and white matter. The tissue is categorized by its neuronal and neuroglial components. Neurons are cells with specialized features that allow them to receive and facilitate nerve impulses, or action potentials, across their membrane to the next neuron. They possess a
20420953
Neuromorphology


and multipolar cells have three or more processes extending towards and away from the cell body. Theoretical neuromorphology is a branch of neuromorphology focused on the mathematical description of the shape, structure and connectivity of the nervous system. Gravitational neuromorphology studies the effects of altered gravity on the architecture of the central, peripheral, and autonomic nervous systems. This subfield aims to expand the current understanding of the adaptive capabilities of nervous systems, and specifically examines how environmental effects can alter nervous system structure and function. In this case environmental manipulations generally include
5685212
Anesthesia


down to three basic goals or endpoints: Different types of anesthesia affect the endpoints differently. Regional anesthesia, for instance, affects analgesia; benzodiazepine-type sedatives (used for sedation, or "twilight anesthesia") favor amnesia; and general anesthetics can affect all of the endpoints. The goal of anesthesia is to achieve the endpoints required for the given surgical procedure with the least risk to the patient. To achieve the goals of anesthesia, drugs act on different but interconnected parts of the nervous system. Hypnosis, for instance
11702699
Niemann–Pick disease


beyond two years of age. Type B patients also show hepatosplenomegaly and pathologic alterations of their lungs but usually without the involvement of their central nervous system. Some can develop significant life-threatening complications including liver failure, hemorrhage, oxygen dependency, pulmonary infections, and splenic rupture. Some develop coronary artery or valvular heart disease. In a longitudinal natural history study, nearly 20% of the patients died. For those classified into type C, they may have mild hepatosplenomegaly, but their central nervous system is profoundly affected. Niemann
2988077
Species-typical behavior


an attack from another creature), the genes that coded for those brain circuits are more likely to be passed on. A heavily studied example of a fixed action pattern is the feeding behavior of the Helisoma trivolvis (pulmonata), a type of snail. A study has shown that the intricate connections within the buccal ganglia (see nervous system of gastropods) form a central system whereby sensory information stimulates feeding in the helisoma. More specifically, a unique system of communication between three classes of neurons in the buccal ganglia are responsible
10272150
Psychophysiological economics


exclusively to the study of brain activity. Psychophysiological economics emphasizes the role of the peripheral nervous system as it relates to shaping economic behavior. The peripheral nervous system includes the spinal and cranial nerves. Of specific relevance is the Autonomic Nervous System (ANS). The ANS regulates glands and other internal organs (visceral structures). Visceral structures control involuntary physiological activities and behavior. Psychophysiological economics researchers directly measure the sympathetic nervous system  as a person responds to stressor within the environment. Three assumptions provide the basis for psychophysiological economics studies.
2416961
Beta blocker


and norepinephrine (noradrenaline) on adrenergic beta receptors, of the sympathetic nervous system, which mediates the fight-or-flight response. Some block activation of all types of β-adrenergic receptors and others are selective for one of the three known types of beta receptors, designated β, β and β receptors. β-adrenergic receptors are located mainly in the heart and in the kidneys. β-adrenergic receptors are located mainly in the lungs, gastrointestinal tract, liver, uterus, vascular smooth muscle, and skeletal muscle
12538774
Vitamin B12


B functions as a coenzyme, meaning that its presence is required for enzyme-catalyzed reactions. Three types of enzymes: In humans, two major coenzyme B-dependent enzyme families corresponding to the first two reaction types, are known. These are typified by the following two enzymes: If folate is present in quantity, then of the two absolutely vitamin B-dependent enzyme-family reactions in humans, the MUT-family reactions show the most direct and characteristic secondary effects, focusing on the nervous system (see below)
15391462
Nervous system network models


column of neurons can be considered as a unit in the mesolevel and regions of the brain comprising a large number of neurons and neuron populations as units in the macrolevel. The links in the latter case are the inter-regional pathways, forming large-scale connectivity. Figure 2 shows the three types of connectivity. The analysis is done using the directed graphs (see Sporns, O. (2007) and Hilgetag, C. C. (2002)). In the structural brain connectivity type, the connectivity is a sparse and directed
7513646
Nervous tissue


as well as provide nutrients to the neurons. Nervous tissue is made up of different types of nerve cells, all of which have an axon. An axon is the long stem-like part of the cell that sends action potential signals to the next cell. Bundles of axons make up the nerves in the PNS and tracts in the CNS. Functions of the nervous system are sensory input integration, control of muscles and glands, homeostasis, and mental activity. Nervous tissue is composed of neurons, also called nerve cells,
20420952
Pavlov's typology


processes. The word "type" is used in two ways in the literature about higher nervous activity: either as a “characteristic pattern of animal behavior or as a complex of the basic properties of the nervous processes.” Pavlov's background as a physiologist greatly influenced his psychological research. His ideas for the how the nervous system works came from his research on the brain, specifically the cortex, and conditioned and unconditioned reflexes, and spurred additional research into the nervous activity that underlies such reflexes. Pavlov introduced the ideas of
4917157
Nerve


the body. Nerves that transmit signals from the brain are called "motor" or "efferent" nerves, while those nerves that transmit information from the body to the CNS are called "sensory" or "afferent". Spinal nerves serve both functions and are called "mixed" nerves. The PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems. Somatic nerves mediate voluntary movement. The autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems. The sympathetic nervous
1710568
Aggression


serotonin transmission may explain a vulnerability to impulsiveness, potential aggression, and may have an effect through interactions with other neurochemical systems. These include dopamine systems which are generally associated with attention and motivation toward rewards, and operate at various levels. Norepinephrine, also known as noradrenaline, may influence aggression responses both directly and indirectly through the hormonal system, the sympathetic nervous system or the central nervous system (including the brain). It appears to have different effects depending on the type of triggering stimulus, for example social isolation/rank
13592747
Grading of the tumors of the central nervous system


also is used to grade astrocytomas; however, this system uses four morphologic criteria to assign a grade: a) "nuclear" "atypia",br b) "mitosis",br c) "endothelial proliferation"-'piled-up' endothelial cells. NOT hypervascularity d) "necrosis". The St. Anne-Mayo grade has four categories of tumors: The World Health Organization (WHO) grading system is contained in the volume "Histological Typing of Tumours of the Central Nervous System", whose first edition dates back to 1979, the second to 1993
2391386
Embryomics


the adult cell lines. hESCs are also immortal, in that they can divide and grow in number indefinitely, without undergoing either differentiation or cellular aging (cellular senescence). The first differentiation of the hESCs that form the embryo proper, is into three cell types known as the germ layers: the ectoderm, the mesoderm, and the endoderm. The ectoderm eventually forms the skin (including hair and nails), mucous membranes and nervous system. The mesoderm forms the skeleton and muscles, heart and circulatory system, urinary and
12848143