Morphology of the insula in relation to hearing status and sign language experience.
We investigated whether auditory deprivation and/or sign language exposure during development alters the macroscopic neuroanatomy of the human insula. Volumetric analyses were based on MRI data from 25 congenitally deaf subjects who were native users of American Sign Language (ASL), 25 hearing subjects with no knowledge of ASL, and 16 hearing subjects who grew up in deaf families and were native ASL signers. Significant variation in insula volume was associated with both hearing status and sign language experience. Compared with both hearing groups, deaf subjects exhibited a significant increase in the amount of gray matter in the left posterior insular lobule, which we hypothesize may be related to the dependence on lip-reading and articulatory-based (rather than auditory-based) representations of speech for deaf individuals. Both deaf and hearing signers exhibited an increased volume of white matter in the right insula compared with hearing nonsigners. We hypothesize that the distinct morphology of the right insula for ASL signers may arise from enhanced connectivity resulting from an increased reliance on cross-modal sensory integration in sign language compared with spoken language.
Allen
John S
JS
Dornsife Cognitive Neuroscience Imaging Center, University of Southern California, Los Angeles, California 90089-2520, USA.
Emmorey
Karen
K
Bruss
Joel
J
Damasio
Hanna
H
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000254:growth & development*; D003638:Deafness / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D005868:Gestures; D006801:Humans; D006984:Hypertrophy / Q000209:etiology; D008085:Lipreading; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology / Q000648:ultrastructure; D009434:Neural Pathways / Q000033:anatomy & histology / Q000254:growth & development; D009473:Neuronal Plasticity / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D012683:Sensory Deprivation / Q000502:physiology; D012813:Sign Language; D012919:Social Behavior; D014705:Verbal Behavior / Q000502:physiology*; D055815:Young Adult