Harold Burton|Abraham Z. Snyder|Jeanmarie Diamond|Marcus E. Raichle
Adaptive Changes in Early and Late Blind: A fMRI Study of Verb Generation to Heard Nouns
Institute of Neurobiology|Washington University in St. Louis|Neurological Surgery|Washington University in St. Louis|Institute of Neurobiology|Institute of Neurobiology|Neurological Surgery|Washington University in St. Louis
literacy blind people requires learning braille along others shown reading braille activates visual cortex includes striate cortex v1 ie banks calcarine sulcus several higher visual areas lingual fusiform cuneus lateral occipital inferior temporal middle temporal gyri spatial extent magnitude magnetic resonance mr signals visual cortex greatest became blind early life individuals lost sight adults subsequently learned braille still exhibited activity visual cortex regions especially v1 findings suggest visual cortex regions become adapted processing tactile information crossmodal neural change might support braille literacy tested alternative hypothesis regions directly respond linguistic aspects task accordingly language task performance blind persons activate visual cortex regions regardless input modality specifically visual cortex activity blind people ought arise language task involving heard words eight early blind six late blind eight sighted subjects studied using functional magnetic resonance imaging fmri covert generation verbs heard nouns control task passive listening indecipherable sounds reverse words matched nouns sound intensity duration spectral content functional responses analyzed level individual subjects using methods based general linear model group level using voxel based anova ttest analyses blind sighted subjects showed comparable activation language areas left inferior frontal dorsolateral prefrontal left posterior superior temporal gyri main distinction bilateral left dominant activation visual cortex regions previously noted braille reading blind subjects spatial extent magnitude responses greatest left early blind individuals responses late blind group mostly confined v1 nearby portions lingual fusiform gyri results confirm presence adaptations visual cortex blind people argue notion activity braille reading represents somatosensory haptic processing rather suggest responses parsimoniously explained terms linguistic operations remains possible responses represent adaptations initially processing either sound touch later generalized modality acquisition braille reading skills