Perceptual facilitation of word recognition through motor activation during sentence comprehension

Published online 29 July 2018Despite the growing literature on anticipatory language processing, the brain dynamics of this high-level predictive process are still unclear. In the present MEG study, we analyzed pre- and post-stimulus oscillatory activity time-locked to the reading of a target word. We experimentally contrasted the processing of the same target word following two highly constraining sentence contexts, in which the constraint was driven either by the semantic content or by the lexical association between words. Previous research suggests the presence of sensory facilitation for expected words in the latter condition but not in the former. We observed a dissociation between beta (∼20 Hz) and gamma (>50 Hz) band activity in pre- and post-stimulus time intervals respectively. Both the beta and gamma effects were evident in occipital brain regions, and only the pre-stimulus beta effect additionally involved left pre-articulatory motor regions. Lexically constrained (vs. semantically constrained) words elicited reduced beta power around 400 msec before the target word in motor regions and a functionally related gamma enhancement in occipital regions around 200 msec post-target. The present findings highlight the role of the motor network in word-form prediction and support proposals claiming that low-level perceptual representations can be pre-activated during language prediction.This work was partially supported by the Spanish Ministry of Economy and Competitiveness (MINECO), the Agencia Estatal de Investigación (AEI) and the (Fondo Europeo de Desarrollo Regional FEDER) (grant PSI2015-65694-P, “Severo Ochoa” programme SEV-2015-490 for Centres of Excellence in R&D), and by the Basque government (grant PI_2016_1_0014). Further support derived from the AThEME project funded by the European Commission 7th Framework Programme, the ERC- 2011-ADG-295362 from the European Research Council