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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 ...
Grey matter is distinguished from white matter in that it contains numerous cell bodies and relatively few myelinated axons, while white matter contains relatively few cell bodies and is composed chiefly of long-range myelinated axons. [1] The colour difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually ...
The cortical layers of neurons constitute much of the cerebral grey matter, while the deeper subcortical regions of myelinated axons, make up the white matter. [7] The white matter of the brain makes up about half of the total brain volume. [16]
The periaqueductal gray (PAG), also known as the central gray, is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. [1] [2] PAG is also the primary control center for descending pain modulation. It has enkephalin-producing cells that suppress pain.
The substantia innominata, also innominate substance or substantia innominata of Meynert (Latin for unnamed substance), is a series of layers in the human brain consisting partly of gray and partly of white matter, which lies below the anterior part of the thalamus and lentiform nucleus.
The projection fibers that make up the corona radiata also radiate out of the brain stem via the internal capsule. Cerebral white matter is viewed as an intricately organized system of fasciculi that facilitate the highest expression of cerebral activity. Part of corona radiata pathway in the brain
In humans, the cerebrum is the largest and best-developed of the five major divisions of the brain. The cerebrum is made up of the two cerebral hemispheres and their cerebral cortices (the outer layers of grey matter), and the underlying regions of white matter. [2] Its subcortical structures include the hippocampus, basal ganglia and olfactory ...
Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interior. Visually, the interior of the brain consists of areas of so-called grey matter, with a dark color, separated by areas of white matter, with a lighter color. Further ...