fMRI Study of Sentence Generation by Early Bilinguals Differing in Proficiency Level

The aim of this study was to identify the functional anatomy of the cerebral speech regions involved in speaking in native and foreign language in the same subject using functional magnetic resonance imaging.

Experimental design consisted of two activation runs. Each of them included two kinds of tasks arranged in series of five blocks lasting for 30s. In the experimental condition of the first run subjects were required to speak in their native language and in the second run the task was to speak in the foreign language. In both runs, baseline condition was the same and subjects were supposed to lie silently inside the bore. We observed the influence of proficiency on brain activation. In subjects with equal proficiency in the first and the second language, differences were not observed. In the subjects with unequal proficiency in the first and the second language we observed two main effects.

First was difference in the strength and extension of activation, the second effect was activation of new regions for the second language, in which proficiency was lower.