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White matter is composed of bundles, which connect various grey matter areas (the locations of nerve cell bodies) of the brain to each other, and carry nerve impulses between neurons. Myelin acts as an insulator, which allows electrical signals to jump , rather than coursing through the axon, increasing the speed of transmission of all nerve ...
They are the most widespread cell lineage, including oligodendrocyte progenitor cells, pre-myelinating cells, and mature myelinating oligodendrocytes in the CNS white matter. [3] Non-myelinating oligodendrocytes are found in the grey matter surrounding and lying next to neuronal cell bodies. They are known as neuronal satellite cells, and their ...
These perisomatic (around the cell body) and basal dendrites project into all cortical layers, but most of their horizontal branches/arbors populate layers V and VI, some reaching down into the white matter. [5] According to one study, Betz cells represent about 10% of the total pyramidal cell population in layer Vb of the human primary motor ...
A deficiency in GALC thus causes a buildup of these fatty acids, leading to an incursion by cells called "globoid macrophages" that destroy oligodendrocytes, thereby inhibiting any further myelin formation. [20] Given the presence of globoid macrophages clustered near white matter, Krabbe disease often is called globoid cell leukodystrophy.
The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. [1] There are more than one million neurons in the corticospinal tract, and they become myelinated usually in the first two years of life.
OPCs comprise approximately 3–4% of cells in grey matter and 8–9% in white matter, making them the fourth largest group of glia after astrocytes, microglia and oligodendrocytes. [6] OPCs are present throughout the brain, including the hippocampus and in all layers of the neocortex. [7]
There are four paired deep cerebellar nuclei embedded in the white matter centre of the cerebellum. The nuclei are the fastigial, globose, emboliform, and dentate nuclei. In lower mammals the emboliform nucleus appears to be continuous with the globose nucleus, and these are known together as the interposed nucleus. [1]
White matter tracts within a human brain, as visualized by MRI tractography A nerve tract is a bundle of nerve fibers ( axons ) connecting nuclei of the central nervous system . [ 1 ] [ 2 ] [ 3 ] In the peripheral nervous system , this is known as a nerve fascicle , and has associated connective tissue .