title: Functional Connectivity Reveals Which Language the "Control Regions" Control during Bilingual Production.
abstract: Bilingual studies have revealed critical roles for the dorsal anterior cingulate cortex (dACC) and the left caudate nucleus (Lcaudate) in controlling language processing, but how these regions manage activation of a bilingual's two languages remains an open question. We addressed this question by identifying the functional connectivity (FC) of these control regions during a picture-naming task by bimodal bilinguals who were fluent in both a spoken and a signed language. To quantify language control processes, we measured the FC of the dACC and Lcaudate with a region specific to each language modality: left superior temporal gyrus (LSTG) for speech and left pre/postcentral gyrus (LPCG) for sign. Picture-naming occurred in either a single- or dual-language context. The results showed that in a single-language context, the dACC exhibited increased FC with the target language region, but not with the non-target language region. During the dual-language context when both languages were alternately the target language, the dACC showed strong FC to the LPCG, the region specific to the less proficient (signed) language. By contrast, the Lcaudate revealed a strong connectivity to the LPCG in the single-language context and to the LSTG (the region specific to spoken language) in the dual-language context. Our findings suggest that the dACC monitors and supports the processing of the target language, and that the Lcaudate controls the selection of the less accessible language. The results support the hypothesis that language control processes adapt to task demands that vary due to different interactional contexts.
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University Beijing, China.
authors.forename: Le
authors.initials: L
authors.lastname: Li
authors.affiliation: Laboratory for Language and Cognitive Neuroscience, School of Speech, Language, and Hearing Sciences, San Diego State University San Diego, CA, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Emmorey
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University Beijing, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China; Centre for Collaboration and Innovation in Brain and Learning SciencesBeijing, China.
authors.forename: Chunming
authors.initials: C
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China; Centre for Collaboration and Innovation in Brain and Learning SciencesBeijing, China.
authors.forename: Guosheng
authors.initials: G
authors.lastname: Ding
keywords: bimodal bilinguals; dorsal anterior cingulate cortex; functional connectivity; language control; left caudate nucleus; signed language