title: Modified areal cartography in auditory cortex following early- and late-onset deafness.
abstract: Cross-modal plasticity following peripheral sensory loss enables deprived cortex to provide enhanced abilities in remaining sensory systems. These functional adaptations have been demonstrated in cat auditory cortex following early-onset deafness in electrophysiological and psychophysical studies. However, little information is available concerning any accompanying structural compensations. To examine the influence of sound experience on areal cartography, auditory cytoarchitecture was examined in hearing cats, early-deaf cats, and cats with late-onset deafness. Cats were deafened shortly after hearing onset or in adulthood. Cerebral cytoarchitecture was revealed immunohistochemically using SMI-32, a monoclonal antibody used to distinguish auditory areas in many species. Auditory areas were delineated in coronal sections and their volumes measured. Staining profiles observed in hearing cats were conserved in early- and late-deaf cats. In all deaf cats, dorsal auditory areas were the most mutable. Early-deaf cats showed further modifications, with significant expansions in second auditory cortex and ventral auditory field. Borders between dorsal auditory areas and adjacent visual and somatosensory areas were shifted ventrally, suggesting expanded visual and somatosensory cortical representation. Overall, this study shows the influence of acoustic experience in cortical development, and suggests that the age of auditory deprivation may significantly affect auditory areal cartography.
authors: Graduate Program in Neuroscience.
authors: Carmen
authors: C
authors: Wong
authors: Department of Physiology and Pharmacology.
authors: Nicole
authors: N
authors: Chabot
authors: Graduate Program in Neuroscience.
authors: Melanie A
authors: MA
authors: Kok
authors: Department of Physiology and Pharmacology, Department of Psychology, Brain and Mind Institute and National Centre for Audiology, The University of Western Ontario, London, ON, Canada.
authors: Stephen G
authors: SG
authors: Lomber
mesh_terms: D000161:Acoustic Stimulation; D017668:Age of Onset; D000704:Analysis of Variance; D000818:Animals; D001303:Auditory Cortex / Q000378:metabolism / Q000503:physiopathology*; D001710:Biotin / Q000031:analogs & derivatives; D002415:Cats; D003051:Cochlea / Q000293:injuries; D003638:Deafness / Q000139:chemically induced / Q000473:pathology*; D003911:Dextrans; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D016900:Neurofilament Proteins / Q000378:metabolism; D012683:Sensory Deprivation / Q000502:physiology; D013238:Stereotaxic Techniques
chemical_list: D003911:Dextrans; D016900:Neurofilament Proteins; C076397:biotinylated dextran amine; D001710:Biotin
keywords: SMI-32; auditory deprivation; cat; cortical plasticity; hearing