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Grey matter contains most of the brain's neuronal cell bodies. [6] The grey matter includes regions of the brain involved in muscle control, and sensory perception such as seeing and hearing, memory, emotions, speech, decision-making, and self-control. The grey matter in the spinal cord is split into three grey columns:
There are two LGNs, one on the left and another on the right side of the thalamus. In humans, both LGNs have six layers of neurons (grey matter) alternating with optic fibers (white matter). The LGN receives information directly from the ascending retinal ganglion cells via the optic tract and from the reticular activating system.
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.
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 ...
The cells of the brain include neurons and supportive glial cells. There are more than 86 billion neurons in the brain, and a more or less equal number of other cells. Brain activity is made possible by the interconnections of neurons and their release of neurotransmitters in response to nerve impulses.
In anatomical sections, a nucleus shows up as a region of gray matter, often bordered by white matter. The vertebrate brain contains hundreds of distinguishable nuclei, varying widely in shape and size. A nucleus may itself have a complex internal structure, with multiple types of neurons arranged in clumps (subnuclei) or layers.
This formation is visible to the naked eye as a white strip running through the cortical grey matter, and is the reason the V1 in primates is also referred to as the "striate cortex." The line of Gennari is due to dense axonal input from the thalamus to layer IV of visual cortex.
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 ...