  The language control network is vital among language-related networks
responsible for solving the problem of multiple language switching. Researchers
have expressed concerns about the instability of the language control network
when exposed to external influences (e.g., Long-term second language learning).
However, some studies have suggested that the language control network is
stable. Therefore, whether the language control network is stable or not
remains unclear. In the present study, we directly evaluated the stability and
instability of the language control network using resting-state functional
magnetic resonance imaging (rs-fMRI). We employed cohorts of Chinese first-year
college students majoring in English who underwent second language (L2)
acquisition courses at a university and those who did not. Two resting-state
fMRI scans were acquired approximately 1 year apart. We found that the language
control network was both moderately stable and unstable. We further
investigated the morphological coexistence patterns of stability and
instability within the language control network. First, we extracted
connections representing stability and plasticity from the entire network. We
then evaluated whether the coexistence patterns were modular (stability and
instability involve different brain regions) or non-modular (stability and
plasticity involve the same brain regions but have unique connectivity
patterns). We found that both stability and instability coexisted in a
non-modular pattern. Compared with the non-English major group, the English
major group has a more non-modular coexistence pattern.. These findings provide
preliminary evidence of the coexistence of stability and instability in the
language control network.
