Language Tasks and the Network Control Role of the Left Inferior Frontal Gyrus

Abstract

Recent work has combined cognitive neuroscience and control theory to make predictions about cognitive control functions. Here, we test a link between whole-brain theories of semantics and the role of the left inferior frontal gyrus (LIFG) in controlled language performance using network control theory, a branch of systems engineering. Specifically, we examined whether two properties of node controllability -boundary and modal controllability -were linked to semantic selection and retrieval on sentence completion and verb generation tasks. We tested whether the controllability of the left IFG moderated language selection and retrieval costs and the effects of continuous theta burst stimulation (cTBS), an inhibitory form of transcranial magnetic stimulation (TMS) on behavior in 41 human subjects (25 active, 16 sham). We predicted that boundary controllabilitya measure of the theoretical ability of a node to integrate and segregate brain networkswould be linked to word selection in the contextually-rich sentence completion task. In contrast, we expected that modal controllabilitya measure of the theoretical ability of a node to drive the brain into specifically hard-to-reach stateswould be linked to retrieval on the low-context verb generation task. Boundary controllability was linked to selection and to the ability of TMS to reduce response latencies on the sentence completion task. In contrast, modal controllability was not linked to performance on the tasks or TMS effects. Overall, our results suggest a link between the network integrating role of the LIFG and selection and the overall semantic demands of sentence completion. Significance StatementOur understanding of language systems and responses to neural stimulation is incomplete. Here, we demonstrate that the effects of neuromodulation (transcranial magnetic stimulation, TMS) on verbal language production are linked to the role of the left inferior frontal gyrus in mediating communication across white matter anatomical networks. We replicate prior findings in weighted anatomical networks, and further identify a link between the role of the LIFG in word selection demands. These findings provide a critical basis to reconcile local and whole brain models of language in the brain.

Disrupted functional connectivity of the habenula links psychomotor retardation and deficit of verbal fluency and working memory in late‐life depression

“…Regarding working memory, the current result is consistent with previous evidence that both the habenula and IFG are associated with working memory, 29 , 33 and it is reasonable that depressive symptoms may disrupt the connection between these two regions and lead to working memory impairment. Regarding the language domain, the IFG is crucial for language production and comprehension, 34 but there is little evidence that the habenula plays a role in language processing. Therefore, the role of the habenula in language processing is likely to be indirect, and further research is needed to elucidate the exact mechanisms and pathways through which the habenula interacts with the IFG or other brain regions to influence language function.…”

Altered neurovascular coupling in children with idiopathic generalized epilepsy

“…to be associated with language processing, 64,65 and the posterior cingulate cortex/precuneus is an important region for concentration and memory. 66 On the other hand, the CBF/DC ratio, CBF, and DC in all brain regions, except the right MFG, were not significantly associated with the neuropsychological assessment scores, disease duration, or age of onset.…”

“…In addition, the CBF/DC ratio changes in regions mainly involved in cognitive control and executive functions may contribute to an intelligence decline in IGE patients. The middle and inferior frontal gyrus have been reported to be associated with language processing, 64,65 and the posterior cingulate cortex/precuneus is an important region for concentration and memory 66 …”

Structure-function models of temporal, spatial, and spectral characteristics of non-invasive whole brain functional imaging

“…Network control models have also been recently extended and applied to investigate controllability in drug-resistant focal epilepsy in children (Chari et al, 2022 ), functional dynamics mediated by controllability of the structural connectivity (Gu et al, 2022 ), prediction of aphasia recovery using controllability measures (Wilmskoetter et al, 2022 ), association of controllability measures with normative negative affect variability (McGowan et al, 2021 ), prediction of positive psychosis spectrum symptoms with controllability measures (Parkes et al, 2021 ), role of controllability measures in language tasks (Medaglia et al, 2021 ), altered energy landscape and stability of working memory representations in schizophrenia (Braun et al, 2021 ), structural control energy in psychosis vulnerability (Zoller et al, 2021 ), and dynamics of controllability measures during seizure progression (Scheid et al, 2021 ).…”