View source for Cortical thickness

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In [[neuroanatomy]], '''cortical thickness''' is a [[brain morphometric]] measure used to describe the combined thickness of the layers of the [[cerebral cortex]] in [[mammal]]ian [[brain]]s, either in local terms or as a global average for the entire brain. Given that cortical thickness roughly correlates with the number of [[neuron]]s within an [[ontogenetic column]], it is often taken as indicative of the [[cognitive]] abilities of an individual, albeit the latter are known to have multiple determinants. In other [[anatomical]] contexts, the term ''cortical thickness'' is also used on occasion to refer to the thickness of the [[renal cortex]] or of [[cortical bone]].

In the living brain, cortical thickness is commonly determined on the basis of the [[grey matter]] set in [[image segmentation|segmented]] [[neuroimaging]] data, usually from the local or average distance between the [[white matter surface]] and the [[pial surface]]. It changes only minimally with [[brain size]], both within and across [[species (biology)|species]]. Its variation across the [[human brain]] follows [[small world|small-world]] principles<ref name=He2007>{{CZ:Ref:He 2007 Small-World Anatomical Networks in the Human Brain Revealed by Cortical Thickness from MRI}}</ref>, and while overall [[sex differences]] in terms of cortical thickness are small in humans, women have slightly higher values in [[temporoparietal]] regions than men<ref name=Sowell2007>{{CZ:Ref:Sowell 2007 Sex differences in cortical thickness mapped in 176 healthy individuals between 7 and 87 years of age}}</ref>. Typical values in adult humans are between 1.5 and 3 [[millimetre|mm]], and during [[aging]], a decrease (also known as [[cortical thinning]]) on the order of about 10 [[micrometre|μm]] per year can be observed <ref name=Salat2004>{{CZ:Ref:Salat 2004 Thinning of the cerebral cortex in aging}}</ref>. Deviations from these patterns can be used as diagnostic indicators for [[brain disorder]]s: While [[Alzheimer's disease]], even very early on, is characterized by pronounced cortical thinning<ref name=Dickerson2009>{{CZ:Ref:Dickerson 2009 The cortical signature of Alzheimer's disease: regionally specific cortical thinning relates to symptom severity in very mild to mild AD dementia and is detectable in asymptomatic amyloid-positive individuals}}</ref>, [[Williams syndrome]] patients exhibit an increase in cortical thickness of about 5-10% in some regions <ref name=Thompson2005>{{CZ:Ref:Thompson 2005 Abnormal Cortical Complexity and Thickness Profiles Mapped in Williams Syndrome}}</ref>, and [[lissencephalic]] patients show drastic thickening, up to several centimetres in occipital regions<ref name=Guerrini2006>{{CZ:Ref:Guerrini 2006 Genetic malformations of cortical development}}</ref>.

==References==
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