Research Paper Title

Modeling essential connections in obsessive-compulsive disorder patients using functional MRI.

Background

Obsessive-compulsive disorder (OCD) is a mental disease in which people experience uncontrollable and repetitive thoughts or behaviours.

Clinical diagnosis of OCD is achieved by using neuropsychological assessment metrics, which are often subjectively affected by psychologists and patients.

In this study, the researchers propose a classification model for OCD diagnosis using functional MR images.

Methods

Using functional connectivity (FC) matrices calculated from brain region of interest (ROI) pairs, a novel Riemann Kernel principal component analysis (PCA) model is employed for feature extraction, which preserves the topological information in the FC matrices.

Hierarchical features are then fed into an ensemble classifier based on the XGBoost algorithm.

Finally, decisive features extracted during classification are used to investigate the brain FC variations between patients with OCD and healthy controls.

Results

The proposed algorithm yielded a classification accuracy of 91.8%.

Additionally, the well-known cortico-striatal-thalamic-cortical (CSTC) circuit and cerebellum were found as highly related regions with OCD.

To further analyse the cerebellar-related function in OCD, the researchers demarcated cerebellum into three sub-regions according to their anatomical and functional property.

Using these three functional cerebellum regions as seeds for brain connectivity computation, statistical results showed that patients with OCD have decreased posterior cerebellar connections.

Conclusions

This study provides a new and efficient method to characterise patients with OCD using resting-state functional MRI.

The researchers also provide a new perspective to analyse disease-related features.

Despite of CSTC circuit, their model-driven feature analysis reported cerebellum as an OCD-related region.

This paper may provide novel insight to the understanding of genetic aetiology of OCD.

Reference

Xing, X., Jin, L., Li, Q., Yang, Q., Han, H., Xu, C., Wei, Z., Zhan, Y., Zhou, X.S., Xue, Z., Chu, X., Peng, Z. & Shi, F. (2020) Modeling essential connections in obsessive-compulsive disorder patients using functional MRI. Brain and Behavior. 10(2):e01499. doi: 10.1002/brb3.1499. Epub 2020 Jan 1.