Artikel
Resting-state fMRI connectivity – a network context for high-resolution language mapping of Broca’s region with transcranial magnetic stimulation
Resting-state fMRT Konnektivität – ein Netzwerk Kontext für hochauflösende Sprachkartierung der Broca-Region mittels transkranieller Magnetstimulation
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Autoren
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Jonas Ort
- Universitätsklinikum RWTH Aachen, Klinik für Neurochirurgie, Aachen, Deutschland
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Katrin Sakreida
- Universitätsklinikum RWTH Aachen, Klinik für Psychiatrie, Psychotherapie und Psychosomatik, Aachen, Deutschland
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Julius Kernbach
- Universitätsklinikum RWTH Aachen, Klinik für Neurochirurgie, Aachen, Deutschland
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Hans Rainer Clusmann
- Universitätsklinikum RWTH Aachen, Klinik für Neurochirurgie, Aachen, Deutschland
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Georg Neuloh
- Universitätsklinikum RWTH Aachen, Klinik für Neurochirurgie, Aachen, Deutschland
| Veröffentlicht: | 26. Juni 2020 |
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Gliederung
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Objective: Navigated transcranial magnetic stimulation (TMS) language mapping yields focal results. For extended interpretability, we correlated resting-state functional MRI connectivity of Broca’s region with a previously found cluster of TMS susceptibility in object naming close to the inferior frontal junction area.
Methods: Twelve healthy, left-dominant native German speakers underwent both magnetic resonance imaging (MRI) and high-resolution TMS language mapping with a 30-target grid systematically covering Broca’s region. Resting-state activity was acquired at 3 Tesla for a duration of 10 minutes. FMRI data were analyzed using the SPM Toolbox CONN with standard preprocessing. Seed-to-network brain connectivity was analyzed based on 30 seed volumes originating from TMS stimulation sites and with the Harvard-Oxford predefined networks as ROIs (excluding the language network of the left inferior frontal gyrus (IFG) to avoid self-correlation). The clustering of seed ROIs was performed using a farthest point algorithm and correlated with previous clustering results based on TMS susceptibility in object naming.
Results: Our clustering approach revealed three coherent clusters (cluster 1: posterior, cluster 2: anterior ventral, cluster 3: dorsal). Cluster 1 showed strong connectivity to lateral senso-motoric networks as well as to parts of the salience/attentional network (e.g. ipsi- and contralateral insula). There is also a distinctive anticorrelation to the default mode network (DMN). Cluster 2 displays connectivity to the classical language networks (e.g., contralateral IFG and ipsilateral superior temporal gyrus). The dorsal Cluster 3 showed connectivity to the ipsilateral frontoparietal networks involved in cognitive control. The focus of TMS inhibition in naming overlapped with clusters 1 and 3 only.
Conclusion: Parcellation of Broca’s region according to TMS and resting-state fMRI reveals different patterns of functionally coherent subregions with only partial overlap. In this study, the focus of TMS susceptibility in naming suggested inhibition of salience processing, cognitive and sensory-motor control rather than language processing proper. In presurgical planning, resting-state fMRI may provide an important complementary network context for focal TMS mapping results.
Figure 1 [Fig. 1]
