Structural-functional connectivity mapping of the insular cortex system: A combined data-driven and meta-analytic topic mapping approach

The insular cortex is an important anatomical integration hub and can serve as a suitable model for exploring structural-functional relationships. In this study, we examined structural and functional magnetic resonance correspondence via the diffusion tensor imaging (DTI) and resting-state functional connectivity (RSFC) profiles of the insular cortex and its mapping with functional networks (FNs) across the brain. We explored these associations primarily by using a data-driven method to independently estimate the structural-functional connectivity in the human insular cortex system. Data were obtained from the Human Connectome Project comprising 108 resting-state functional magnetic resonance neuroimaging (fMRI) and DTI. Brain networks were acquired and defined according to the seven Yeo FNs. In general, we observed moderate to high association between the structural and functional mapping results of three distinct insular subregions: the posterior insula (sensorimotor: RSFC, DTI = 50%, 72%, respectively), dorsal anterior insula (ventral attention: RSFC, DTI = 83%, 83%, respectively), and ventral anterior insula (frontoparietal: RSFC, DTI = 42%, 89%, respectively). We also examined the cognitive and behavioral domains associated with these three insular subregions using meta-analytic topic mapping and found cognitive and behavioral relations to affective processes, reflecting the core properties of the cytoarchitecture. In sum, given the core role of the insula in the human brain, our findings on the correspondence of the insular cortex system between DTI and RSFC mappings provide a novel approach and insight for clinical researchers to detect dysfunctional brain organization in various neurological disorders. Significance Statement The insula is a suitable model for exploring the structural and functional relationships of the human brain. However, the correspondence between the connectivity profiles of the insula to FNs as derived from DTI and RSFC mapping is not adequately investigated. Here, we combined DTI and RSFC approaches to investigate the structural–functional correspondence of the insular cortex system. Our results revealed moderate to high overlap between the structural and functional mappings of the insular subregions, suggesting that a simple model of direct anatomical connectivity can elucidate the correlations in neuronal activity. The meta-analytic topic mapping approach further provided better inference for the cognitive and behavioral relations of the different insular subregions. ### Competing Interest Statement The authors have declared no competing interest.