Mapping the Neural Patterns of Verbal Repetition: An Activation Likelihood Estimation Meta-Analysis

Verbal repetition is a core language function that integrates receptive and expressive processes in a temporally constrained manner. This integrative nature makes it particularly relevant for language acquisition and learning, while also giving it strong clinical importance. Deficits in repetition are hallmark symptoms of several language disorders, and repetition tasks are systematically included in major diagnostic batteries and therapeutic protocols. Although verbal repetition has been widely investigated, the heterogeneity of findings across studies has left its consistent neural underpinnings insufficiently established. This study aims to: i) identify the brain regions consistently activated during verbal repetition in healthy participants, irrespective of experimental design; ii) examine the distinct patterns related to word and pseudoword repetition; and iii) investigate the lateralization of these processes. A coordinate-based meta-analysis using Activation Likelihood Estimation (ALE) was conducted on 440 activation foci (380 participants) from 27 functional magnetic resonance experiments investigating verbal repetition. Results revealed a bilaterally distributed fronto-temporo-parietal network, with additional involvement of the supplementary motor area and the cingulate cortex, consistently associated with general verbal repetition. When comparing word and pseudoword repetition, pseudowords elicited greater activation convergence in left fronto-temporal regions and right subcortical structures, while word repetition showed greater activation convergence in the mid part of the bilateral superior temporal gyrus and the left supplementary motor area. However, lateralization indexes showed a predominant left lateralization for all repetition processes. In conclusion, this meta-analysis provides a comprehensive overview of consistent brain regions involved in verbal repetition in healthy adults.