(Not in Brain Scans etc
Figure 3.2. This figure shows the results for grammatical processing of the study of Wartenburger et al. (2003) (see text for details). Results for three groups of bilinguals are displayed: early-acquisition bilinguals (left), late-acquisition and high-proficient bilinguals (middle), and late-acquisition and low-proficient bilinguals (right). The images refer to direct comparisons between L2 and L1 (subtracting L1 from L2 within each group in order to show whether L2 activates a more extended neural system for grammatical processing).
As demonstrated, the degree of L2 proficiency does not seem to have strong influences on the pattern of brain activity. The late-acquisition and high-proficient group used the same additional brain activity as the low-proficiency group. Only when L2 was acquired early in life, was the same pattern of brain activity found (left) (modified from Wartenburger et al., 2003).