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Changes in Effective Connectivity in the Language and Multiple-Demand Network after Left Temporo-Parietal and Frontal Stroke

Poster B31 in Poster Session B and Reception, Thursday, October 6, 6:30 - 8:30 pm EDT, Millennium Hall
Also presenting in Poster Slam B, Thursday, October 6, 6:15 - 6:30 pm EDT, Regency Ballroom

Zhizhao Jiang^1,2, Anika Stockert², Philipp Kuhnke^1,3, Max Wawrzyniak², Gesa Hartwigsen¹, Dorothee Saur²; ¹Lise Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Language and Aphasia Laboratory, Department of Neurology, University of Leipzig Medical Centre, Germany, ³Germany Wilhelm Wundt Institute for Psychology, University of Leipzig, Germany

Stroke often severely affects language function. A better understanding of post-stroke language recovery is crucial to identify reorganisation mechanisms and improve clinical interventions. Previous neuroimaging work demonstrated distinct mechanisms during different phases of language reorganisation after stroke: global network disturbance during the acute phase, upregulation of the bilateral domain-general multiple-demand network (MDN) and restitution of perilesional cortex during the subacute phase, and reintegration of left temporal language areas during the chronic phase (1-2). These previous studies further suggest that phase-specific mechanisms depend on individual lesion sites. However, changes in the interactions within and between the language network and MDN during language recovery have not been explored yet. To fill this gap, the present study examined changes in the effective connectivity between core areas of both networks after temporo-parietal and frontal stroke in the left hemisphere. We investigated the directed functional connections and their modulation by intelligible speech (SP) and unintelligible reversed speech (REV) during the acute, subacute, and chronic phases using Dynamic Causal Modelling (DCM) and Parametric Empirical Bayes (PEB) framework (3-4). We performed effective connectivity analyses with a dataset of two patient groups (n=17 in each group) with left temporo-parietal or frontal stroke, and 17 healthy controls. 6 regions-of-interests (ROIs) were selected based on the language-related activation in Stockert et al. (2): bilateral inferior frontal gyrus (IFG), bilateral dorsolateral prefrontal cortex, left posterior temporal lobe (PTL) and left supplementary motor area/ dorsal anterior cingulate cortex. For individual-level analysis, a full model was specified and estimated for each participant. The full model assumed full connectivity via reciprocal connections. The onset of all auditory stimuli was set as driving input to all ROIs, and SP and REV were used as modulatory inputs. At the group level, connection strengths of each subject were entered into a PEB model to compare the differences between patients and controls. Preliminary results suggest that, in general, domain-general regions exerted a facilitatory influence onto language areas during recovery. This facilitatory influence was further increased by both SP and REV. For patients with frontal stroke, in the acute phase, the facilitatory intrinsic connectivity from right to left IFG was increased by SP and REV. In the subacute phase, only REV increased the facilitatory influence from right to left IFG. In the chronic phase, the intrinsic connection from right to left IFG became non-significant, but REV turned the non-significant connection facilitatory, which was similar in controls. As an unexpected finding, we did not observe significant facilitatory interactions between left IFG and left PTL in either patient group. These results support the notion that domain-general areas are crucial for language recovery after stroke. Our preliminary findings further suggest changes in the interaction between language and domain-general areas across the time course of recovery. 1. Saur, D.et al. (2006). Brain, 129, 1371-1384. 2. Stockert, A. et al. (2020). Brain, 143(3), 844-861. 3. Zeidman, P. et al. (2019a). NeuroImage, 200, 174-190. 4. Zeidman, P. et al. (2019b). NeuroImage, 200, 12-25.

Topic Areas: Disorders: Acquired, Speech Perception