Cortical complexity analysis of patients with bipolar disorder using three-dimensional gyrification index.

Bipolar disorder (BD) is a common affective disorder. In morphometric brain imaging studies, BD subjects have atrophic gray matter, especially in the prefrontal area. These structural abnormalities could involve the change of cortical shape. Gyrification index (GI) is a useful metric to measure the degree of cortical complexity. This work aims to compare the cortical development between bipolar patients and healthy controls using GI. No significant difference was detected between two groups. However, we found asymmetry pattern of cortical complexity was increased in limbic lobe on bipolar patients. Significant negative correlation was also observed between rating scores and asymmetry coefficients in frontal lobe.