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

• Published in: Human brain mapping Vol. 42; no. 3; pp. 699 - 712
• Main Authors: Trettenbrein, Patrick C., Papitto, Giorgio, Friederici, Angela D., Zaccarella, Emiliano
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 15.02.2021
• Subjects: Acoustics; Brain architecture; Brain Mapping; Broca Area - diagnostic imaging; Broca Area - physiology; Broca's area; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Deafness - diagnostic imaging; Deafness - physiopathology; Frontal gyrus; Frontal lobe; Functional anatomy; Functional Laterality - physiology; Hemispheric laterality; Hominids; Humans; Language; Linguistics; Medical imaging; Meta-analysis; modality‐independence; Nerve Net - diagnostic imaging; Nerve Net - physiology; Neural networks; Neuroimaging; Psycholinguistics; Sign Language; Speech; modality-independence; sign language; meta-analysis; Broca's area
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.25254

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 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. Sign language (SL) conveys linguistic information using gestures instead of sounds. Here, we apply a meta‐analytic approach to neuroimaging studies and ask whether SL comprehension in deaf signers relies on the same primarily left‐hemispheric cortical network implicated in spoken and written language comprehension in hearing speakers. We find that SL‐specific voxels in Broca's area are also crucially involved in spoken and written language, suggesting that the human brain evolved a lateralized language network with a supramodal hub in Broca's area which computes linguistic information independent of speech.