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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 VBM analysis showed global gray matter was decreased linearly with age, especially for men, whereas global white matter did not decline with age. A key description of the methodology of voxel-based morphometry is Voxel-Based Morphometry—The Methods [ 9 ] —one of the most cited articles in the journal NeuroImage . [ 10 ]
There is a difference between the cerebral blood volume of gray and white matter. The cerebral blood volume value of gray matter is about 3.5 +/- 0.4 ml/100g, and the white matter is about 1.7 +/- 0.4 ml/100g. The gray matter is nearly twice that of white matter. [3]
This allows researchers to quantify anatomical features of the brain in terms of shape, mass, volume (e.g. of the hippocampus, or of the primary versus secondary visual cortex), and to derive more specific information, such as the encephalization quotient, grey matter density and white matter connectivity, gyrification, cortical thickness, or ...
Grey matter, or gray 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.
Microscopically, there are differences between the neurons and tissue of the CNS and the peripheral nervous system (PNS). [11] The CNS is composed of white and gray matter. [9] This can also be seen macroscopically on brain tissue. The white matter consists of axons and oligodendrocytes, while the gray matter consists of neurons and
Age-related decrease in gray matter volume was the largest contribution to changes in brain volume. Moreover, neuronal density appears to decrease, white matter microstructure gets altered and energy metabolism in the cerebellum gets altered. [16] General cortical atrophy occurs in aging and e.g. the caudate nucleus volume appears to decrease.
Each cerebral hemisphere has an outer layer of cerebral cortex which is of grey matter and in the interior of the cerebral hemispheres is an inner layer or core of white matter known as the centrum semiovale. [3] The interior portion of the hemispheres of the cerebrum includes the lateral ventricles, the basal ganglia, and the white matter. [4]