Gray matter voxel-based morphometry in mania and remission states of children with bipolar disorder

It has been found by many studies that gray matter (GM) abnormalities exist in both adults and children with bipolar disorder (PBD) which is a serious mental illness characterized by alternating episodes of mania and depression. However, there are few studies on the comparison between brain imaging of different mood states shown by patients with bipolar disorder. This study is aimed at exploring the differences existing in brain structures between children with bipolar disorder and that of healthy controls, and then it tries to further explore whether there is a structural difference between the states of mania and remission in children with bipolar disorder.

21 PBD-mania subjects, 19 PBD-remission subjects and 18 control subjects aged 12-17 years old were engaged in this study. In the present study, magnetic resonance imaging was obtained by employing a Siemens 3.0 T scanner. With regard to the volumes of gray matter in the mania group, remission group and healthy control group, analysis was carried out by using voxel-based morphometry (VBM). Further analysis was conducted on the correlation between MRI data and clinical features of patients with PBD.

In comparison with the healthy control subjects, the gray matter volume measured from the left hippocampus, parahippocampal gyrus and amygdala in both manic and euthymic groups showed a decreasing trend, while the volume of left orbitofrontal cortex increased. However, no significant difference in volumes was found between BD manic and euthymic groups. It was observed that the volume of orbitofrontal cortex had a positive correlation with onset age in PBD euthymic group.

Our study came to the conclusion that extensive brain structural changes are available in patients with PBD. The brain regions with structural changes are distributed in the anterior limbic network (ALN), which has been proved to have been involved in the abnormal emotional and cognitive regulation of PBD. However, there is no difference in the volumes of gray matter between mania and remission in PBD .