Structural And Functional Magnetic Resonance Imaging Study Of Pediatric Bipolar Disorder

Objective:Pediatric bipolar disorder (PBD) is a severely debilitating illness, which is characterized by episodes of mania and depression separated by periods of remission. Previous fMRI studies investigating PBD were mainly emotion or cognition-related. However, little is known about the abnormalities in PBD, especially about both emotional and cognitive neural circuit. Research about emotional and cognitive neural circuit was our purpose. And we also wanted to study whether activity was changed when disease was remitted.Methods:1. The structural MRI was examined on18patients with PBD in manic state,15patients with PBD in euthymic state, with18age-and sex-matched healthy youth subjects as controls.2. We used emotional go/no go as task stimuli. All the emotional faces were chosed from’Pictures Of Facial Affect (Ekman,1976)’. The pictures chosed were evaluated for recognition rate among healthy adolescents. The task-related fMRI study was examined on15patients with PBD in manic state,13patients with PBD in euthymic state, with15age-and sex-matched healthy youth subjects as controls.3. Regional homogeneity (ReHo) was examined with resting-state fMRI (RS-fMRI) on19patients with PBD in manic state,17patients with PBD in euthymic state, with19age-and sex-matched healthy youth subjects as controls.Results:1. The results of variance of structural MRI showed altered activity in the following brain regions:left hippocampus, parahippocampus gyrus and amygdala. Compared with the healthy control, the manic and euthymic patients showed reduced volume in left hippocampus, parahippocampus gyrus and amygdala. The volume of these regions was not correlated with age, clinical course and number of episodes.2. While emotional distractors compared with neural distracors, the results of variance of task-state MRI showed altered activity in the following brain regions:bilateral superior frontal gyrus, bilateral dorsomedial prefrontal cortex, left dorsolateral prefrontal cortex, bilateral orbitofrontal cortex, left dorsal anterior cigulate cortex, right ventral anterior cingulate cortex, right posterior cingulate cortex, bilateral superior/middle temporal lobe, right putamen, bilateral insula, bilateral hippocampus, left parahippocampus gyrus, bilateral thalamus, bilateral superior/inferior parietal lobe, bilateral cuneus/precuneus and bilateral middle/inferior occipital gyrus. Compared with the euthymic patients, the manic patients showed increased activity in the left dorsolateral prefrontal cortex and left superior parietal lobe. 3. The results of variance of Resting-state MRI showed altered ReHo in the following brain regions:right superior frontal gyrus, right precentral gyrus, right orbitofrontal cortex, right dorsal anterior cigulate cortex, bilateral superior temporal lobe, bilateral insula, bilateral superior parietal lobe and bilateral precuneus. Compared with the euthymic patients, the manic patients showed reduced ReHo in bilateral precuneus and increased ReHo in the bilateral insula.Conclusions:This study presents new evidence for abnormal ventral-affective and dorsal-cognitive circuits in PBD and may add fresh insights into the pathophysiological mechanisms underlying PBD.