Dendrite complexity of the posterior cingulate cortex as a substrate for recovery from post-stroke depression: A pilot study

The neural basis of recovery from a depressive state remains poorly understood. The main purpose of this study was to determine the neural basis of vulnerability/resilience to depression in stroke patients in terms of changes in regional microstructure. The study included 20 individuals with acute ischaemic stroke. Symptoms of depression were assessed, and the intraneurite volume fraction and neurite orientation-dispersion index (ODI) were evaluated by a multi-shell diffusion imaging and neurite-orientation dispersion and density imaging model. Patients underwent follow-up examinations after 2 months and were classified into depression improvement and depression deterioration groups. A significant interaction effect of group × time on the ODI was shown by voxel-based analysis in the posterior cingulate cortex (PCC). The ODI change in the PCC was negatively correlated with the change in the depression scale scores at the 2-month time point. The increase in ODI in the PCC that occurred during the 2-month interval was thought to be associated with decreased depressive symptom scores. As the ODI represents the pattern of sprawling dendrite progression, our findings indicate that the dendritic complexity of the PCC is a substrate for recovery in individuals who experienced post-stroke psychosocial and biological stress.