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Cortical Homunculus
A cortical homunculus () is a distorted representation of the human body, based on a neurological "map" of the areas and proportions of the human brain dedicated to processing motor functions, or sensory functions, for different parts of the body. Nerve fibresconducting somatosensory information from all over the bodyterminate in various areas of the parietal lobe in the cerebral cortex, forming a representational map of the body. Types A motor homunculus represents a map of brain areas dedicated to ''motor'' processing for different anatomical divisions of the body. The primary motor cortex is located in the precentral gyrus, and handles signals coming from the premotor area of the frontal lobes. A sensory homunculus represents a map of brain areas dedicated to ''sensory'' processing for different anatomical divisions of the body. The primary sensory cortex is located in the postcentral gyrus, and handles signals coming from the thalamus. The thalamus itself receiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Homunculus-en
Sensory may refer to: Biology * Sensory ecology, how organisms obtain information about their environment * Sensory neuron, nerve cell responsible for transmitting information about external stimuli * Sensory perception, the process of acquiring and interpreting sensory information * Sensory receptor, a structure that recognizes external stimuli * Sensory system, part of the nervous system of organisms Business and brands * Sensory, Inc., an American speech technology company Other uses * Sensory analysis, a consumer product-testing method * Sensory garden, a self-contained garden area that allows visitors to enjoy a wide variety of sensory experiences See also * Sensor A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ... * Sense (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postcentral Gyrus
In neuroanatomy, the postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the '' sensory homunculus''. The primary somatosensory cortex was initially defined from surface stimulation studies of Wilder Penfield, and parallel surface potential studies of Bard, Woolsey, and Marshall. Although initially defined to be roughly the same as Brodmann areas 3, 1 and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it receives the bulk of the thalamocortical projections from the sensory input fields. Structure The lateral postcentral gyrus is bounded by: * medial longitudinal fissure medially (to the middle) *central sulcus rostrally (in front) * pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Systems
The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, touch, taste, smell, and balance. Senses are transducers from the physical world to the realm of the mind where people interpret the information, creating their perception of the world around them. The receptive field is the area of the body or environment to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field; the light that each rod or cone can see, is its receptive field. Receptive fields have been identified for the visual system, auditory system and somatosensory system. Stimulus :Organisms need information to solve at least three kinds of problems: (a) to maintain an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole-rat
Mole-rat or mole rat can refer to several groups of burrowing Old World rodents: * Bathyergidae, a family of about 20 hystricognath species in six genera from Africa also called blesmols. *'' Heterocephalus glaber'', the naked mole-rat. * Spalacidae, a family of about 30 muroid species in six genera from Eurasia and northeast Africa, including: **'' Tachyoryctes'', a genus of about 15 species from Africa; ** Blind mole rats (Spalacinae), a subfamily of about 15 living species in the genus '' Spalax'' from southeastern Europe, southwestern Asia, and northeastern Africa; ** Zokors (Myospalacinae), occasionally called mole-rats, about eight species from central and eastern Asia. * In the family Muridae: ** ''Nesokia indica'' from southern and southwestern Asia and Egypt, also known as the short-tailed mole-rat. ** ''Bandicota bengalensis The lesser bandicoot rat, Sindhi rice rat, bengal rat or Indian mole-rat (''Bandicota bengalensis'') is a giant rat of Southern Asia, not relate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Motor Cortex
The primary motor cortex (Brodmann area 4) is a Human brain, brain region that in humans is located in the dorsal portion of the frontal lobe. It is the primary cortex, primary region of the motor system and works in association with other motor areas including premotor cortex, the supplementary motor area, posterior parietal cortex, and several subcortical brain regions, to plan and execute voluntary movements. Primary motor cortex is defined anatomically as the region of cortex that contains large neurons known as Betz cells, which, along with other cortical neurons, send long axons down the spinal cord to synapse onto the interneuron circuitry of the spinal cord and also directly onto the alpha motor neurons in the spinal cord which connect to the muscles. At the primary motor cortex, motor representation is orderly arranged (in an inverted fashion) from the toe (at the top of the cerebral hemisphere) to mouth (at the bottom) along a fold in the cortex called the central sulcu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Magnetic Resonance Imaging
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa in 1990. This is a type of specialized brain and body scan used to map neural activity in the brain or spinal cord of humans or other animals by imaging the change in blood flow (hemodynamic response) related to energy use by brain cells. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not involve the use of injections, surgery, the ingestion of substances, or exposure to ionizing radiation. This measure is frequently corrupted by noise from various sources; hence, statistical procedures are used to extract the underlying signal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatotopic Arrangement
Somatotopy is the point-for-point correspondence of an area of the body to a specific point on the central nervous system. Typically, the area of the body corresponds to a point on the primary somatosensory cortex (postcentral gyrus). This cortex is typically represented as a sensory homunculus which orients the specific body parts and their respective locations upon the homunculus. Areas such as the appendages, digits, penis, and face can draw their sensory locations upon the somatosensory cortex. The areas which are finely controlled (e.g., the digits) have larger portions of the somatosensory cortex whereas areas which are coarsely controlled (e.g., the trunk) have smaller portions. Areas such as the viscera do not have sensory locations on the post central gyrus. Macaques, a kind of monkey, already exhibit somatotopy in their somatosensory and motor systems at birth. Sensorimotor mapping of the human cerebellum Functional magnetic resonance imaging (fMRI) was employed to deter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilder Penfield
Wilder Graves Penfield (January 26, 1891April 5, 1976) was an American-Canadian neurosurgeon. He expanded brain surgery's methods and techniques, including mapping the functions of various regions of the brain such as the cortical homunculus. His scientific contributions on neural stimulation expand across a variety of topics including hallucinations, illusions, and '' déjà vu''. Penfield devoted much of his thinking to mental processes, including contemplation of whether there was any scientific basis for the existence of the human soul. Biography Early life and education Born in Spokane, Washington, on January 26, 1891, Penfield spent most of his early life in Hudson, Wisconsin. He studied at Princeton University, where he was a member of Cap and Gown Club and played on the football team. After graduation in 1913, he was hired briefly as the team coach. In 1915 he obtained a Rhodes Scholarship to Merton College, Oxford, where he studied neuropathology under Sir Cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory And Motor Homunculi
Sensory may refer to: Biology * Sensory ecology, how organisms obtain information about their environment * Sensory neuron, nerve cell responsible for transmitting information about external stimuli * Sensory perception, the process of acquiring and interpreting sensory information * Sensory receptor, a structure that recognizes external stimuli * Sensory system, part of the nervous system of organisms Business and brands * Sensory, Inc., an American speech technology company Other uses * Sensory analysis, a consumer product-testing method * Sensory garden, a self-contained garden area that allows visitors to enjoy a wide variety of sensory experiences See also * Sensor A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ... * Sense (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Stimulation
Sexual stimulation is any stimulus (including bodily contact) that leads to, enhances and maintains sexual arousal, and may lead to orgasm. Although sexual arousal may arise without physical stimulation, achieving orgasm usually requires physical sexual stimulation. The term ''sexual stimulation'' often implies stimulation of the genitals, but may also include stimulation of other areas of the body, stimulation of the senses (such as sight or hearing) and mental stimulation (i.e. from reading or fantasizing). Sufficient stimulation of the penis or clitoris usually results in an orgasm. Stimulation can be by self (e.g., masturbation) or by a sexual partner (sexual intercourse or other sexual activity), by use of objects or tools, or by some combination of these methods. Some people practice orgasm control, whereby a person or their sexual partner controls the level of sexual stimulation to delay orgasm, and to prolong the sexual experience leading up to orgasm. Physical sexua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and second lumbar vertebrae, where it ends. The enclosing bony vertebral column protects the relatively shorter spinal cord. It is around long in adult men and around long in adult women. The diameter of the spinal cord ranges from in the cervical and lumbar regions to in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain Stem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch, and sometimes the diencephalon is included in the brainstem. The brainstem is very small, making up around only 2.6 percent of the brain's total weight. It has the critical roles of regulating cardiac, and respiratory function, helping to control heart rate and breathing rate. It also provides the main motor and sensory nerve supply to the face and neck via the cranial nerves. Ten pairs of cranial nerves come from the brainstem. Other roles include the regulation of the central nervous system and the body's sleep cycle. It is also of prime importance in the conveyance of motor and sensory pathways from the rest of the brain to the body, and from the body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
