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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 6 cortex layers migrate from the ventricular zone through the subplate to come to rest in the cortical plate (layers 2 through 6) or in the marginal zone (layer 1) The preplate also contains the predecessor to the subplate, which is sometimes referred to as a layer. As the cortical plate appears, the preplate separates into two components.
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 ...
Beneath the cortex is the cerebral white matter. The largest part of the cerebral cortex is the neocortex, which has six neuronal layers. The rest of the cortex is of allocortex, which has three or four layers. [7] The cortex is mapped by divisions into about fifty different functional areas known as Brodmann's areas.
Cortical white matter increases from childhood (~9 years) to adolescence (~14 years), most notably in the frontal and parietal cortices. [8] Cortical grey matter development peaks at ~12 years of age in the frontal and parietal cortices, and 14–16 years in the temporal lobes (with the superior temporal cortex being last to mature), peaking at about roughly the same age in both sexes ...
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 ...
The cerebral cortex, also known as the cerebral mantle, [1] is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals.It is the largest site of neural integration in the central nervous system, [2] and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness.
White matter, which is mostly composed of myelinated axons (hence its white color) and glial cells, is generally not considered to be a part of the neuropil. [citation needed] Neuropil (pl. neuropils) comes from the Greek: neuro, meaning "tendon, sinew; nerve" and pilos, meaning "felt". [2] The term's origin can be traced back to the late 19th ...