gray matter

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1. physical material having form and weight under ordinary conditions; called also substance.
2. pus.
gray matter areas of the nervous system where the nerve fibers are unmyelinated (not enveloped by a myelin sheath); it contains the bodies of the nerve cells. Tissue composed of myelinated fibers is called white matter. The cerebral cortex is entirely composed of gray matter and the cerebellum also contains some deep-seated masses of it. The spinal cord has a central core of gray matter surrounded by white matter; in cross section, its gray matter is shaped approximately like the letter H. Called also substantia grisea and gray substance.
white matter areas of the nervous system composed mostly of myelinated nerve fibers (those having myelin sheaths) constituting the conducting portion of the brain and spinal cord. Tissue composed of unmyelinated fibers is called gray matter. Called also substantia alba and white substance.

gray mat·'ter

those regions of the brain and spinal cord that are made up primarily of the cell bodies and dendrites of nerve cells rather than myelinated axons.

gray matter

1. Brownish-gray nerve tissue, especially of the brain and spinal cord, composed of nerve cell bodies and their dendrites and some supportive tissue.
2. Informal Brains; intellect.

gray matter

the gray nervous tissue found in the cortex of the cerebrum and cerebellum and the core of the spinal cord. It is predominantly composed of neuron cell bodies and unmyelinated axons. The gray color is produced by cytoplasmic elements seen in all cell bodies and processes not covered by whitish myelin. Nuclei in the gray substance of the spinal cord function as centers for all spinal reflexes. Also called gray substance. Compare white matter. See also cerebellum, cerebral cortex, cerebrum, spinal cord, spinal nerves.
Nonmyelinated cells and circuitry that comprise the ‘central processing unit’ of the CNS and spinal cord; the thinking part of the brain, which is composed of neuronal cell bodies, initial axon segments, dendritic processes, and arborizations, glia—neuroglial cells—capillaries and vascular support; gray matter is so named because it appears grayish; brain gray matter is peripheral; spinal cord gray matter is central

gray mat·ter

(grā mat'ĕr) [TA]
Those regions of the brain and spinal cord that are made up primarily of the cell bodies and dendrites of nerve cells rather than myelinated axons.
Synonym(s): substantia grisea [TA] , gray substance.

gray matter

gray areas of brain and spinal cord made up primarily of cell bodies and dendrites of nerve cells rather than myelinated axons. White matter or substance is the tissue composed primarily of myelinated, or medullated, fibers.
The bodies of the nerve cells are centered in the gray matter. In the brain the gray matter may be external to white matter, e.g. cerebellum, or central to it, e.g. cerebrum. The cerebral cortex is composed of gray matter and there are some deep-seated nuclei too. In the spinal cord there is a central core of gray matter surrounded by white matter. On a cross-section of the spinal cord the gray matter follows the general pattern of the letter H.
References in periodicals archive ?
It is important to note that the changes in gray matter volume do not stem from a loss or gain in brain cells.
Ge, who noted that his MFC findings support observations made using diffusion tensor imaging and MR spectroscopy demonstrating gray matter involvement in MS.
Although the researchers found a negative correlation between gray matter and age in both groups of people -- suggesting a loss of brain tissue with increasing age -- they also found that large parts of the gray matter in the brains of those who meditated seemed to be better preserved, Kurth said.
In contrast with the gray matter findings, the extent and location of white matter deficits was very similar in the schizophrenia and bipolar families, said Dr.
After 4 weeks, about the time it takes for lithium's mood-stabilizing effects to emerge, the drug had increased the volume of brain gray matter by about 3 percent in 8 of the 10 people studied, the researchers report this week at the Society for Neuroscience meeting in New Orleans.
Gray matter early in development appears to enable flexibility; children can play and excel at many different activities.
Progressive loss of brain gray matter (GM) has been reported in childhood-onset schizophrenia; however, it is uncertain whether these changes are shared by pediatric patients with different psychoses," the researchers said.
Diwadkar has compiled an aggregate MRI of 22 healthy adolescents that reveals a very characteristic pattern of systematic reduction of gray matter in the prefrontal, parietal, and temporal lobes.
The skipper's command reverberated in my gray matter with sickening adhesiveness.
Kinney knew previous studies had shown that people in a persistent vegetative state suffer extensive damage to the cerebral cortex, the gray matter that forms the outer layer of the human brain.
Washington, Aug 31 (ANI): A new research has revealed that decline in hearing ability may accelerate gray matter atrophy in auditory areas of the brain thereby increasing the listening effort necessary for older people to successfully comprehend speech.
The gray matter in the parietal lobes of children with Down syndrome is preserved, despite their overall smaller brain volumes, reported Dr.