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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 ...
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.
The neocortex consists of the grey matter, or neuronal cell bodies and unmyelinated fibers, surrounding the deeper white matter ( myelinated axons) in the cerebrum. This is a very thin layer though, about 2–4 mm thick. [ 6] There are two types of cortex in the neocortex, the proisocortex and the true isocortex.
The periaqueductal gray is the gray matter located around the cerebral aqueduct within the tegmentum of the midbrain. It projects to the nucleus raphe magnus, and also contains descending autonomic tracts. The ascending pain and temperature fibers of the spinothalamic tract send information to the PAG via the spinomesencephalic pathway (so ...
The anterior and posterior grey columns present as projections of grey matter and are also known as the horns of the spinal cord. The white matter is located outside of the grey matter and consists almost totally of myelinated motor and sensory axons. Columns of white matter known as funiculi carry information either up or down the spinal cord.
Reviews of neuroimaging studies indicate that consistent aerobic exercise increases gray matter volume in nearly all regions of the brain, [31] with more pronounced increases occurring in brain regions associated with memory processing, cognitive control, motor function, and reward; [1] [5] [31] the most prominent gains in gray matter volume are seen in the prefrontal cortex, caudate nucleus ...
Nervous tissue is made up of different types of neurons, all of which have an axon. An axon is the long stem-like part of the cell that sends action potentials 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 ...
The brain is very complex, and is composed of many different areas and types of tissue, or matter. The different functions of different tissues in the brain may be more or less susceptible to age-induced changes. [6] The brain matter can be broadly classified as either grey matter, or white matter.