Congenital deafness affects deep layers in primary and secondary auditory cortex. Issue 14 (13th July 2017)

• Record Type: Journal Article
• Authors: Berger, Christoph; Kühne, Daniela; Scheper, Verena; Kral, Andrej
• Is Part Of: Journal of comparative neurology. Volume 525:Issue 14(2017)
• Page Start: 3110
• Page End: 3125
• Publication Date: 2017-07-13
• Subjects: cortical column -- cochlear implant -- development -- hearing loss -- higher‐order areas -- infragranular layers -- RRID: AB_509997; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24267
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: Congenital deafness leads to functional deficits in the auditory cortex for which early cochlear implantation can effectively compensate. Most of these deficits have been demonstrated functionally. Furthermore, the majority of previous studies on deafness have involved the primary auditory cortex; knowledge of higher‐order areas is limited to effects of cross‐modal reorganization. In this study, we compared the cortical cytoarchitecture of four cortical areas in adult hearing and congenitally deaf cats (CDCs): the primary auditory field A1, two secondary auditory fields, namely the dorsal zone and second auditory field (A2); and a reference visual association field (area 7) in the same section stained either using Nissl or SMI‐32 antibodies. The general cytoarchitectonic pattern and the area‐specific characteristics in the auditory cortex remained unchanged in animals with congenital deafness. Whereas area 7 did not differ between the groups investigated, all auditory fields were slightly thinner in CDCs, this being caused by reduced thickness of layers IV–VI. The study documents that, while the cytoarchitectonic patterns are in general independent of sensory experience, reduced layer thickness is observed in both primary and higher‐order auditory fields in layer IV and infragranular layers. The study demonstrates differences in effects of congenital deafness between supragranular and other cortical layers, but similar dystrophic effects in all investigated auditory fields. Abstract : Cytoarchitectonics in primary and higher‐order auditory cortical areas was not affected by congenital auditory deprivation (deafness). Reduced layer thickness in deep cortical layers IV–VI of primary and higher‐order areas was observed, despite cross‐modal reorganization in some of them. Cross‐modal reorganization did not protect the cortex from dystrophic changes.