Editing Neocortex (section)

===Geometry===

The neocortex is smooth in [[rodent]]s and other small mammals, whereas in [[elephant]]s, [[dolphins]] and [[primate]]s and other larger mammals it has deep grooves ([[sulcus (neuroanatomy)|sulci]]) and ridges ([[gyrus|gyri]]). These folds allow the surface area of the neocortex to be greatly increased. All human brains have the same overall pattern of main gyri and sulci, although they differ in detail from one person to another.<ref name="Moerel,2006">{{cite journal | vauthors = Moerel M, De Martino F, Formisano E |title = An anatomical and functional topography of human auditory cortical areas. |journal = Front. Neurosci. |volume = 8 |issue = 225 |pages =  225|date = 2006 |pmid =  25120426|pmc = 4114190 |doi =  10.3389/fnins.2014.00225|quote = For example, in the human brain, the auditory cortex presents an expansion of cortical surface, with additional gyri and with a much larger inter-individual variability...|doi-access = free }}</ref> The mechanism by which the gyri form during embryogenesis is not entirely clear, and there are several competing hypotheses that explain gyrification, such as axonal tension,<ref name="Van Essen 1997">{{cite journal | vauthors = Van Essen DC | title = A tension-based theory of morphogenesis and compact wiring in the central nervous system | journal = Nature | volume = 385 | issue = 6614 | pages = 313–8 | date = January 1997 | pmid = 9002514 | doi = 10.1038/385313a0 | s2cid = 4355025 | url = http://person.hst.aau.dk/06gr1088d/artikler/Pdf/A%20tension-based%20theory%20of%20morphogenesis%20and%20compact%20wiring%20in%20the%20central%20nervous%20system.pdf }}</ref> cortical buckling<ref name="Richman 1975">{{cite journal | vauthors = Richman DP, Stewart RM, Hutchinson JW, Caviness VS | title = Mechanical model of brain convolutional development | journal = Science | volume = 189 | issue = 4196 | pages = 18–21 | date = July 1975 | pmid = 1135626 | doi = 10.1126/science.1135626 }}</ref> or differences in cellular proliferation rates in different areas of the cortex.<ref name="Ronan 2013">{{cite journal | vauthors = Ronan L, Voets N, Rua C, Alexander-Bloch A, Hough M, Mackay C, Crow TJ, James A, Giedd JN, Fletcher PC | title = Differential tangential expansion as a mechanism for cortical gyrification | journal = Cerebral Cortex | volume = 24 | issue = 8 | pages = 2219–28 | date = August 2014 | pmid = 23542881 | pmc = 4089386 | doi = 10.1093/cercor/bht082 | url = }}</ref>