Qin Kun, Sweeney John A, DelBello Melissa P
Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH 45219, USA.
Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, China.
Psychoradiology. 2022 Dec 6;2(4):171-179. doi: 10.1093/psyrad/kkac022. eCollection 2022 Dec.
Bipolar disorder (BD) is a familial disorder with high heritability. Genetic factors have been linked to the pathogenesis of BD. Relatives of probands with BD who are at familial risk can exhibit brain abnormalities prior to illness onset. Given its involvement in prefrontal cognitive control and in frontolimbic circuitry that regulates emotional reactivity, the inferior frontal gyrus (IFG) has been a focus of research in studies of BD-related pathology and BD-risk mechanism. In this review, we discuss multimodal neuroimaging findings of the IFG based on studies comparing at-risk relatives and low-risk controls. Review of these studies in at-risk cases suggests the presence of both risk and resilience markers related to the IFG. At-risk individuals exhibited larger gray matter volume and increased functional activities in IFG compared with low-risk controls, which might result from an adaptive brain compensation to support emotion regulation as an aspect of psychological resilience. Functional connectivity between IFG and downstream limbic or striatal areas was typically decreased in at-risk individuals relative to controls, which could contribute to risk-related problems of cognitive and emotional control. Large-scale and longitudinal investigations on at-risk individuals will further elucidate the role of IFG and other brain regions in relation to familial risk for BD, and together guide identification of at-risk individuals for primary prevention.
双相情感障碍（BD）是一种具有高遗传性的家族性疾病。遗传因素与BD的发病机制有关。处于家族风险中的BD先证者的亲属在疾病发作前可能会出现大脑异常。鉴于其参与前额叶认知控制以及调节情绪反应性的额边缘回路，额下回（IFG）一直是BD相关病理学和BD风险机制研究的重点。在本综述中，我们基于比较高危亲属和低危对照的研究，讨论IFG的多模态神经影像学研究结果。对这些高危病例研究的综述表明，存在与IFG相关的风险和恢复力标志物。与低危对照相比，高危个体的IFG灰质体积更大且功能活动增加，这可能是大脑适应性补偿的结果，以支持作为心理恢复力一个方面的情绪调节。相对于对照，高危个体中IFG与下游边缘或纹状体区域之间的功能连接通常会降低，这可能导致与风险相关的认知和情绪控制问题。对高危个体进行大规模和纵向研究将进一步阐明IFG和其他脑区在BD家族风险中的作用，并共同指导识别高危个体以进行一级预防。
