Editing Auditory cortex (section)

==Structure==
The auditory cortex was previously subdivided into primary (A1) and secondary (A2) projection areas and further association areas. The modern divisions of the auditory cortex are the core (which includes primary auditory cortex, A1), the belt (secondary auditory cortex, A2), and the parabelt (tertiary auditory cortex, A3). The belt is the area immediately surrounding the core; the parabelt is adjacent to the lateral side of the belt.<ref "name=Pickles2012p211f">Cf. Pickles, James O. (2012). ''An Introduction to the Physiology of Hearing'' (4th ed.). Bingley, UK: Emerald Group Publishing Limited, p. 211 f.</ref>

Besides receiving input from the ears via lower parts of the auditory system, it also transmits signals back to these areas and is interconnected with other parts of the cerebral cortex. Within the core (A1), its structure preserves [[tonotopy]], the orderly representation of frequency, due to its ability to map low to high frequencies corresponding to the apex and base, respectively, of the [[cochlea]].

Data about the auditory cortex has been obtained through studies in rodents, cats, macaques, and other animals. In humans, the structure and function of the auditory cortex has been studied using [[functional magnetic resonance imaging]] (fMRI), [[electroencephalography]] (EEG), and [[electrocorticography]].<ref>{{cite journal|last1=Moerel|first1=Michelle|last2=De Martino|first2=Federico|last3=Formisano|first3=Elia|title=An anatomical and functional topography of human auditory cortical areas|journal=Frontiers in Neuroscience|date=29 July 2014|volume=8|page=225|doi=10.3389/fnins.2014.00225|pmid=25120426|pmc=4114190|doi-access=free}}</ref><ref>{{cite journal|last1=Rauschecker|first1=Josef P|last2=Scott|first2=Sophie K|title=Maps and streams in the auditory cortex: nonhuman primates illuminate human speech processing|journal=Nature Neuroscience|date=26 May 2009|volume=12|issue=6|pages=718–724|doi=10.1038/nn.2331|pmid=19471271|pmc=2846110}}</ref>

===Development===
Like many areas in the neocortex, the functional properties of the adult primary auditory cortex (A1) are highly dependent on the sounds encountered early in life. This has been best studied using animal models, especially cats and rats. In the rat, exposure to a single frequency during postnatal day (P) 11 to 13 can cause a 2-fold expansion in the representation of that frequency in A1.<ref>{{cite journal|last=de Villers-Sidani|first=Etienne|author2=EF Chang |author3=S Bao |author4=MM Merzenich |title=Critical period window for spectral tuning defined in the primary auditory cortex (A1) in the rat|journal=J Neurosci|volume=27|issue=1|pages=180–9|doi=10.1523/JNEUROSCI.3227-06.2007|year=2007|pmid=17202485|pmc=6672294|url=https://cloudfront.escholarship.org/dist/prd/content/qt20p2h3wt/qt20p2h3wt.pdf}}</ref> Importantly, the change is persistent, in that it lasts throughout the animal's life, and specific, in that the same exposure outside of that period causes no lasting change in the tonotopy of A1. Sexual dimorphism within the auditory cortex can be seen in humans between males in females through the planum temporale, encompassing Wernicke's region, for the planum temporale within males has been observed to have a larger planum temporale volume on average, reflecting previous studies discussing interactions between sex hormones and asymmetrical brain development.<ref>{{Cite journal|last1=Kulynych|first1=J. J.|last2=Vladar|first2=K.|last3=Jones|first3=D. W.|last4=Weinberger|first4=D. R.|date=March 1994|title=Gender differences in the normal lateralization of the supratemporal cortex: MRI surface-rendering morphometry of Heschl's gyrus and the planum temporale|journal=Cerebral Cortex |volume=4|issue=2|pages=107–118|doi=10.1093/cercor/4.2.107|issn=1047-3211|pmid=8038562}}</ref>