title: Ultra-fast speech comprehension in blind subjects engages primary visual cortex, fusiform gyrus, and pulvinar - a functional magnetic resonance imaging (fMRI) study.
abstract: BACKGROUND
  Individuals suffering from vision loss of a peripheral origin may learn to understand spoken language at a rate of up to about 22 syllables (syl) per second - exceeding by far the maximum performance level of normal-sighted listeners (ca. 8 syl/s). To further elucidate the brain mechanisms underlying this extraordinary skill, functional magnetic resonance imaging (fMRI) was performed in blind subjects of varying ultra-fast speech comprehension capabilities and sighted individuals while listening to sentence utterances of a moderately fast (8 syl/s) or ultra-fast (16 syl/s) syllabic rate.
  
  
  RESULTS
  Besides left inferior frontal gyrus (IFG), bilateral posterior superior temporal sulcus (pSTS) and left supplementary motor area (SMA), blind people highly proficient in ultra-fast speech perception showed significant hemodynamic activation of right-hemispheric primary visual cortex (V1), contralateral fusiform gyrus (FG), and bilateral pulvinar (Pv).
  
  
  CONCLUSIONS
  Presumably, FG supports the left-hemispheric perisylvian "language network", i.e., IFG and superior temporal lobe, during the (segmental) sequencing of verbal utterances whereas the collaboration of bilateral pulvinar, right auditory cortex, and ipsilateral V1 implements a signal-driven timing mechanism related to syllabic (suprasegmental) modulation of the speech signal. These data structures, conveyed via left SMA to the perisylvian "language zones", might facilitate - under time-critical conditions - the consolidation of linguistic information at the level of verbal working memory.
authors.affiliation: Center for Neurology/Department of General Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Str, 3, D-72076, Tübingen, Germany. susanne.dietrich@med.uni-tuebingen.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Dietrich
authors.forename: Ingo
authors.initials: I
authors.lastname: Hertrich
authors.forename: Hermann
authors.initials: H
authors.lastname: Ackermann
mesh_terms: D000328:Adult; D001766:Blindness; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D032882:Comprehension / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D020649:Pulvinar / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology; D019987:Persons with Visual Disabilities