The formation of the spinal nerve from the dorsal and ventral roots (with grey matter labelled at centre right).
Micrograph showing grey matter, with the characteristic neuronal cell bodies (dark shade of pink), and white matter with its characteristic fine meshwork-like appearance (left of image; lighter shade of pink). HPS stain.
Grey matter, or brain matter in American English, is a major component of the central nervous system, consisting of neuronalcell 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 bodies and relatively few myelinated axons, while white matter contains relatively few cell bodies and is composed chiefly of long-range myelinated axons.[1] The colour difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually has a very light grey colour with yellowish or pinkish hues, which come from capillary blood vessels and neuronal cell bodies.[2]
Grey matter in the spinal cord is known as the grey column which travels down the spinal cord distributed in three grey columns that are presented in an "H" shape. The forward-facing column is the anterior grey column, the rear-facing one is the posterior grey column and the interlinking one is the lateral grey column. The grey matter on the left and right side is connected by the grey commissure. The grey matter in the spinal cord consists of interneurons, as well as the cell bodies of projection neurons.
Cross-section of a spinal vertebra with the spinal cord in the centre (and grey matter labelled).
Cross-section of spinal cord with the grey matter labelled.
Grey matter undergoes development and growth throughout childhood and adolescence.[3] Recent studies using cross-sectional neuroimaging have shown that by around the age of 8 the volume of grey matter begins to decrease.[4] However, the density of grey matter appears to increase as a child develops into early adulthood.[4] Males tend to exhibit grey matter of increased volume but lower density than that of females.[5]
Function
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:
The grey matter of the spinal cord can be divided into different layers, called Rexed laminae. These describe, in general, the purpose of the cells within the grey matter of the spinal cord at a particular location.
Interneurons present in the grey matter of the spinal cord
Rexed laminae groups the grey matter in the spinal cord according to its function.
Clinical significance
High alcohol consumption has been correlated with significant reductions in grey matter volume.[7][8] Short-term cannabis use (30 days) is not correlated with changes in white or grey matter.[9] However, several cross-sectional studies have shown that repeated long-term cannabis use is associated with smaller grey matter volumes in the hippocampus, amygdala, medial temporal cortex, and prefrontal cortex, with increased grey matter volume in the cerebellum.[10][11][12] Long-term cannabis use is also associated with alterations in white matter integrity in an age-dependent manner,[13] with heavy cannabis use during adolescence and early adulthood associated with the greatest amount of change.[14]
Habitual playing of action video games has been reported to promote a reduction of grey matter in the hippocampus while 3D platformer games have been reported to increase grey matter in the hippocampus.[20][21][22]
Women and men with equivalent IQ scores have differing proportions of grey to white matter in cortical brain regions associated with intelligence.[23]
Pregnancy renders substantial changes in brain structure, primarily reductions in grey matter volume in regions subserving social cognition. The grey matter reductions endured for at least 2 years post-pregnancy.[24] The profile of brain changes is comparable to that taking place during adolescence, a hormonally similar transitional period of life.[25]
History
Etymology
In the current edition[26] of the official Latin nomenclature, Terminologia Anatomica, substantia grisea is used for English grey matter. The adjective grisea for grey is however not attested in classical Latin.[27] The adjective grisea is derived from the French word for grey, gris.[27] Alternative designations like substantia cana[28] and substantia cinerea[29] are being used alternatively. The adjective cana, attested in classical Latin,[30] can mean grey,[27] or greyish white.[31] The classical Latin cinerea means ash-coloured.[30]
Additional images
Human brain right dissected lateral view
Schematic representation of the chief ganglionic categories (I to V).
^Purves D, Augustine GJ, Fitzpatrick D, Hall WC, LaMantia AS, McNamara JO, White LE (2008). Neuroscience (4th ed.). Sinauer Associates. pp. 15–16. ISBN978-0-87893-697-7.
^Kolb B, Whishaw IQ (2003). Fundamentals of human neuropsychology (5th ed.). New York: Worth Publishing. p. 49. ISBN978-0-7167-5300-1.
^Miller AK, Alston RL, Corsellis JA (1980). "Variation with age in the volumes of grey and white matter in the cerebral hemispheres of man: measurements with an image analyser". Neuropathology and Applied Neurobiology. 6 (2): 119–32. doi:10.1111/j.1365-2990.1980.tb00283.x. PMID7374914. S2CID23201991.
^Yang X, Tian F, Zhang H, Zeng J, Chen T, Wang S, Jia Z, Gong Q (July 2016). "Cortical and subcortical gray matter shrinkage in alcohol-use disorders: a voxel-based meta-analysis". Neuroscience and Biobehavioral Reviews. 66: 92–103. doi:10.1016/j.neubiorev.2016.03.034. PMID27108216. S2CID19928689.
^Xiao P, Dai Z, Zhong J, Zhu Y, Shi H, Pan P (August 2015). "Regional gray matter deficits in alcohol dependence: A meta-analysis of voxel-based morphometry studies". Drug and Alcohol Dependence. 153: 22–8. doi:10.1016/j.drugalcdep.2015.05.030. PMID26072220.
^Lorenzetti V, Lubman DI, Whittle S, Solowij N, Yücel M (September 2010). "Structural MRI findings in long-term cannabis users: what do we know?". Substance Use & Misuse. 45 (11): 1787–808. doi:10.3109/10826084.2010.482443. PMID20590400. S2CID22127231.
^Matochik JA, Eldreth DA, Cadet JL, Bolla KI (January 2005). "Altered brain tissue composition in heavy marijuana users". Drug and Alcohol Dependence. 77 (1): 23–30. doi:10.1016/j.drugalcdep.2004.06.011. PMID15607838.
^Hoekzema E, Barba-Müller E, Pozzobon C, Picado M, Lucco F, García-García D, Soliva JC, Tobeña A, Desco M, Crone EA, Ballesteros A, Carmona S, Vilarroya O (February 2017). "Pregnancy leads to long-lasting changes in human brain structure". Nature Neuroscience. 20 (2): 287–296. doi:10.1038/nn.4458. hdl:1887/57549. PMID27991897. S2CID4113669.
^ abcTriepel H (1910). Die anatomischen Namen. Ihre Ableitung und Aussprache. Mit einem Anhang: Biographische Notizen (3rd ed.). Wiesbaden: Verlag J.F. Bergmann.[page needed]
^Triepel H (1910). Nomina Anatomica. Mit Unterstützung von Fachphilologen. Wiesbaden: Verlag J.F. Bergmann.[page needed]
^Schreger CH (1805). "Synonymia anatomica. Synonymik der anatomischen Nomenclatur". In Fürth (ed.). Bureau für Literatur.[page needed]
^ abLewis CT, Short C (1879). A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary. Oxford: Clarendon Press.[page needed]
^Stearn WT (1983). Charles D (ed.). Botanical Latin. History, grammar, syntax, terminology and vocabulary (3rd ed.). London: Newton Abbot.[page needed]
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