Functional neuroanatomy of language without speech: An ALE meta-analysis of sign language

Hum Brain Mapp. 2021 Feb 15;42(3):699-712. doi: 10.1002/hbm.25254. Epub 2020 Oct 28.


Sign language (SL) conveys linguistic information using gestures instead of sounds. Here, we apply a meta-analytic estimation approach to neuroimaging studies (N = 23; subjects = 316) and ask whether SL comprehension in deaf signers relies on the same primarily left-hemispheric cortical network implicated in spoken and written language (SWL) comprehension in hearing speakers. We show that: (a) SL recruits bilateral fronto-temporo-occipital regions with strong left-lateralization in the posterior inferior frontal gyrus known as Broca's area, mirroring functional asymmetries observed for SWL. (b) Within this SL network, Broca's area constitutes a hub which attributes abstract linguistic information to gestures. (c) SL-specific voxels in Broca's area are also crucially involved in SWL, as confirmed by meta-analytic connectivity modeling using an independent large-scale neuroimaging database. This strongly suggests that the human brain evolved a lateralized language network with a supramodal hub in Broca's area which computes linguistic information independent of speech.

Keywords: Broca's area; meta-analysis; modality-independence; sign language.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Brain Mapping*
  • Broca Area / diagnostic imaging
  • Broca Area / physiology*
  • Cerebral Cortex / diagnostic imaging
  • Cerebral Cortex / physiology*
  • Deafness / diagnostic imaging
  • Deafness / physiopathology*
  • Functional Laterality / physiology*
  • Humans
  • Nerve Net / diagnostic imaging
  • Nerve Net / physiology*
  • Psycholinguistics*
  • Sign Language*