The role of the supplementary motor area (SMA) in word production

Fx Alario (1, 2) , Hanna Chainay (3, 4, 5) , Stéphane Lehéricy (6, 4) , Laurent Cohen (2, 7, 4)

1 LPC - Laboratoire de psychologie cognitive
2 LCogn - Neuroimagerie cognitive
3 UBO UFR LSH - Université de Bretagne Occidentale - UFR Lettres et sciences humaines
4 CHU Pitié-Salpêtrière [AP-HP]
5 EMC - Laboratoire d'Etude des Mécanismes Cognitifs
6 Service de Neuroradiologie [CHU Lariboisière]
7 UPMC - Université Pierre et Marie Curie - Paris 6

The supplementary motor area (SMA) is a key structure for behavioral planning and execution. Recent research on motor control conducted with monkeys and humans has put to light an anatomical and functional distinction between pre-SMA and SMA-proper. According to this view, the pre-SMA would be involved in higher level processes while the SMA-proper would be more closely tied to motor output. We extended this general framework to the verbal domain, in order to investigate the role of the SMA in speech production. We conducted two speech production experiments with fMRI where we manipulated parameters such as familiarity, complexity or constraints on word selection. The results reveal a parcellation of the SMA into three distinct regions, according to their involvement in different aspects of word production. More specifically, following a rostrocaudal gradient, we observed differential activations related to lexical selection, linear sequence encoding and control of motor output. A parallel organization was observed in the dorsolateral frontal cortex. By refining its anatomical and functional parcellation, these results clarify the roles of the SMA in speech production.

Domaines: Psychologie

Fx Alario, Hanna Chainay, Stéphane Lehéricy, Laurent Cohen. The role of the supplementary motor area (SMA) in word production. Brain Research, 2006, 1076 (1), pp.129-143. ⟨10.1016/j.brainres.2005.11.104⟩. ⟨hal-01440645⟩