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Grey matter, or brain matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distinguished from white matter in that it contains numerous cell bodies ...
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
Subventricular zone OPCs are activated and then migrate away from germinal [14] zones to populate both developing white and gray matter, where they differentiate and mature into myelin-forming oligodendrocytes. [10] [15] However, it is not clear whether all oligodendrocyte progenitors undergo this sequence of events. [16]
OPCs continue to exist in both white and grey matter in the adult brain and maintain their population through self-renewal. [29] [30] White matter OPCs proliferate at higher rates and are best known for their contributions to adult myelinogenesis, while grey matter OPCs are slowly proliferative or quiescent and mostly remain in an immature state.
Development of the cerebral cortex. The development of the cerebral cortex, known as corticogenesis is the process during which the cerebral cortex of the brain is formed as part of the development of the nervous system of mammals including its development in humans. The cortex is the outer layer of the brain and is composed of up to six layers.
The glia to neuron-ratio in the cerebral cortex is 3.72 (60.84 billion glia (72%); 16.34 billion neurons), while that of the cerebellum is only 0.23 (16.04 billion glia; 69.03 billion neurons). The ratio in the cerebral cortex gray matter is 1.48, with 3.76 for the gray and white matter combined. [27]
The sensory and motor regions matured first after which the rest of the cortex developed. This was characterized by loss of grey matter and it occurred from the posterior to the anterior region. This loss of grey matter and increase of white matter may occur throughout a lifetime though the more robust changes occur from childhood to ...
Myelin (/ ˈmaɪ.əlɪn / MY-ə-lin) is a lipid -rich material that surrounds nerve cell axons (the nervous system's electrical wires) to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. [1][2] The myelinated axon can be likened to an electrical wire (the axon) with insulating ...