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Neural Plasticity
Volume 2016, Article ID 7217630, 9 pages
http://dx.doi.org/10.1155/2016/7217630
Research Article

The Right Hemisphere Planum Temporale Supports Enhanced Visual Motion Detection Ability in Deaf People: Evidence from Cortical Thickness

1Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
2International Laboratory for Brain, Music, and Sound Research (BRAMS), Montreal, QC, Canada H2V 4P3
3Centre for Research on Brain, Language, and Music (CRBLM), Montreal, QC, Canada H3G 2A8
4École d’Orthophonie et d’Audiologie, Université de Montréal, Montreal, QC, Canada H3N 1X7
5Centre de Recherche Interdisciplinaire en Réadaptation du Montréal Métropolitain, Institut Raymond-Dewar, Montreal, QC, Canada H2L 4G9

Received 19 August 2015; Revised 16 November 2015; Accepted 18 November 2015

Academic Editor: Jyoti Mishra

Copyright © 2016 Martha M. Shiell et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl’s gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area’s involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity.