Abstract
Sign languages are natural languages expressed by a distinct set of linguistic articulators: the hands, face, and body. Several neuroimaging studies of the neural substrates underlying sign production have observed the recruitment of brain regions previously identified as being involved in speech production, despite the difference in production channels. However, no prior work has provided a statistical synthesis of this available literature. Here, we report a pre-registered meta-analysis of the published positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) literature on sign language production (N experiments = 15, N participants = 168). Combining an Activation Likelihood Estimation (ALE) approach with jackknife re-sampling to validate the robustness of our findings, we identify four clusters consistently associated with the production of single signs across studies in the literature located in (1) left inferior frontal gyrus including BA 45 and extending into (2) left anterior insula, (3) the left superior frontal gyrus, and (4) the medial and right cerebellum. Meta-analytic connectivity modelling using data from a large-scale database of neuroimaging studies confirmed that the IFG, insula, and SFG clusters observed for sign language production are also recruited for spoken language production and comprehension. Moreover, our results also highlight the importance of the cerebellum during sign production and indicate modality-dependent convergence patterns in cerebellar subregions. In sum, our findings complement prior work on sign language comprehension and spoken language production, suggesting substantial overlap in the neural substrates of language processing and production-related mechanisms between sign and spoken language.