The neural bases of meaningful intransitive gestures: A meta-analysis of lesion and fMRI studies.

Meaningful intransitive (MFI) gestures have long been used by clinicians and researchers to assess gesture production and recognition, especially in the context of neuropsychological disorders like apraxia. Their neural bases, however, remain unclear. The goal of this systematic, theory-driven meta-analysis of 6 lesion studies and 21 fMRI studies was to investigate the cerebral networks of MFI gestures. The results suggested that MFI gesture processing depends on a large, left-lateralized, cortico-subcortical, fronto-temporo-insular and cerebellar neural network also involved in social cognition and skills. A bilateral cluster was also found in medial and cingulate brain regions. The left inferior parietal lobe, typically involved in tool use and imitation skills, was part of this network for gesture production - although it did not survive statistical control. These results challenge traditional neurocognitive models and suggest that MFI gestures, although represented widely in the brain, call for specific socio-cognitive processes. The discussion offers a comprehensive framework of the neural bases of MFI gestures, along with methodological considerations and future directions.