Distinct neural networks associated with obsession and delusion: a connectome-wide association study.

BACKGROUND: Obsession and delusion are theoretically distinct from each other in terms of reality testing. Despite such phenomenological distinction, no extant studies have examined the identification of common and distinct neural correlates of obsession and delusion by employing biologically grounded methods. Here, we investigated dimensional effects of obsession and delusion spanning across the traditional diagnostic boundaries reflected upon the resting-state functional connectivity (RSFC) using connectome-wide association studies (CWAS). METHODS: Our study sample comprised of 96 patients with obsessive-compulsive disorder, 75 patients with schizophrenia, and 65 healthy controls. A connectome-wide analysis was conducted to examine the relationship between obsession and delusion severity and RFSC using multivariate distance-based matrix regression. RESULTS: Obsession was associated with the supplementary motor area, precentral gyrus, and superior parietal lobule, while delusion was associated with the precuneus. Follow-up seed-based RSFC and modularity analyses revealed that obsession was related to aberrant inter-network connectivity strength. Additional inter-network analyses demonstrated the association between obsession severity and inter-network connectivity between the frontoparietal control network and the dorsal attention network. CONCLUSIONS: Our CWAS study based on the Research Domain Criteria (RDoC) provides novel evidence for the circuit-level functional dysconnectivity associated with obsession and delusion severity across diagnostic boundaries. Further refinement and accumulation of biomarkers from studies embedded within the RDoC framework would provide useful information in treating individuals who have some obsession or delusion symptoms but cannot be identified by the category of clinical symptoms alone.

Altered functional network architecture in orbitofronto-striato-thalamic circuit of unmedicated patients with obsessive-compulsive disorder.

Dysfunction of corticostriatal loops has been proposed to underlie certain cognitive and behavioral problems associated with various neuropsychiatric disorders, such as obsessive-compulsive disorder (OCD) characterized by repetitive, unwanted thoughts, and behaviors. Although functional abnormalities in the loops involving the orbitofronto-striato-thalamic (OFST) circuitry in patients with OCD have been reported, our understanding of a link between disruptions in the architecture of the intrinsic functional network of the OFST circuit and their symptoms remain incomplete. Using resting-state functional MRI in conjunction with unsupervised clustering and multilevel functional connectivity (FC) techniques, FC of the OFST network and its topological organization in 61 OCD patients versus 61 matched controls were characterized. Patients exhibited disruptions in small-world properties of the OFST circuit, which indicates an imbalance between functional integration and segregation. Patients also showed decreased FC between the central orbitofrontal cortex and dorsomedial striatum but increased FC between the medial thalamus and striatal areas. Using one of the largest samples of unmedicated OCD patients to date, our findings provide evidence supporting the OFST dysconnection hypothesis in OCD as a basic pathophysiological mechanism underlying the disorder, showing the disruption of FC between specific cortical, striatal, and thalamic clusters and aberrant topological patterns of the OFST circuit. Hum Brain Mapp 38:109-119, 2017. © 2016 Wiley Periodicals, Inc.

Beyond Domain-Specific Expertise: Neural Signatures of Face and Spatial Working Memory in Baduk (Go Game) Experts.

Recent advances of neuroimaging methodology and artificial intelligence have resulted in renewed interest in board games like chess and Baduk (called Go game in the West) and have provided clues as to the mechanisms behind the games. However, an interesting question that remains to be answered is whether the board game expertise as one of cognitive skills goes beyond just being good at the trained game and how it maps on networks associated with cognitive abilities that are not directly trained. To address this issue, we examined functional activity and connectivity in Baduk experts, compared to novices, while performing a visual n-back working memory (WM) task. We found that experts, compared to novices, had greater activation in superior parietal cortex during face WM, though there were no group differences in behavioral performances. Using a data-driven, whole-brain multivariate approach, we also found significant group differences in the multivariate pattern of connectivity in frontal pole and inferior parietal cortex, further showing greater connectivity between frontal and parietal regions and between frontal and temporal regions in experts. Our findings suggest that long-term trained Baduk experts have the reorganization of functional interactions between brain regions even for untrained cognitive ability.