Neural Correlates of Implicit and Explicit Learning of Foreign Language Syntax: An fMRI Study

One of the fundamental questions in second language acquisition is whether language can be learned explicitly through conscious learning of language rules or whether it can be acquired implicitly in the context of meaningful language use. Although a large body of behavioral research has addressed the issue, how implicit and explicit contexts mediate the neural representation of language has not been well characterized [1][2].Method 32 Persian speakers were randomly assigned to the implicit or explicit conditions to learn French in three sessions. The explicit condition provided formal instruction on the underlying grammatical rules as well as 40 meaningful examples, whereas the implicit condition presented 140 meaningful examples and no explicit grammar rules were provided. Following the training sessions, fMRI data were acquired using a rapid-presentation event-related design while participants completed a timed grammaticality judgment task. Results The whole-brain analysis revealed that both groups activated a rather large network of language-relevant regions in the frontal, temporal and parietal lobes when processing L2 syntax. However, learners in the explicit group showed a more left-lateralized response pattern to processing of both syntactic and violation sentences (as evidenced by the activation of the left BA6). In addition, region of interest (ROI) analysis revealed the involvement of both declarative memory structures, i.e. the hippocampus, the parahippocampal gyrus and the left BA47 as well as procedural memory structures, i.e. the putamen and the precentral gyrus (BA6) (Table 1).Conclusions Both groups appeared to rely on areas related to L1 grammar (BA6) but also activated areas of attention and control for the syntactic task (as evidenced by the activation of the posterior cingulate gyrus and insula). Moreover, the pattern of activity revealed by ROI analysis was consistent with the Declarative/Procedural model which predicts that grammar relies on both declarative and procedural memory systems [3].