New insights into the neural foundations mediating movement/language interactions gained from intrasurgical direct electrostimulations
Résumé
Interactions between language and motricity have been a topic of interest in brain development as well as in pathological models. The role of the motor system in language has been investigated through neuroimaging and non-invasive brain stimulation methods. However, little is known about the neural basis that might be involved in such interactions. Meanwhile, brain direct electrostimulations (DES) have provided essential knowledges about the connectomic organization of both motor and language systems. We propose here to review the literature about DES from the outlook of interactions between language and motricity and to investigate common cortico-subcortical structures shared by both networks. Then we will report an experimental study about the spatial distribution of DES eliciting simultaneous speech and contralateral upper limb negative motor response in a series of 100 patients operated on under awake condition for a low-grade glioma. From the probabilistic map obtained, a structural connectivity analysis was performed to reveal the cortico-subcortical networks involved in language and motricity interactions. The embodiment suggested by these results takes place in parallel and distributed bilateral fronto-temporo-parietal networks rather than in a single and somatopically well defined organization as previously suggested.