Amygdala abnormalities are widely documented in bipolar spectrum disorders (BSD). Amygdala volume typically is measured after BSD onset; thus, it is not known whether amygdala abnormalities predict BSD risk or relate to the disorder. Additionally, past literature often treated the amygdala as a homogeneous structure, and did not consider its distinct subnuclei and their differential connectivity to other brain regions. To address these issues, we used a behavioral high‐risk design and diffusion‐based subsegmentation to examine amygdala subnuclei among medication‐free individuals with, and at risk for, BSD. The behavioral high‐risk design (N = 114) included low‐risk (N = 37), high‐risk (N = 47), and BSD groups (N = 30). Diffusion‐based subsegmentation of the amygdala was conducted to determine whether amygdala volume differences related to particular subnuclei. Individuals with a BSD diagnosis showed greater whole, bilateral amygdala volume compared to Low‐Risk individuals. Examination of subnuclei revealed that the BSD group had larger volumes compared to the High‐Risk group in both the left medial and central subnuclei, and showed larger volume in the right lateral subnucleus compared to the Low‐Risk group. Within the BSD group, specific amygdala subnuclei volumes related to time since first episode onset and number of lifetime episodes. Taken together, whole amygdala volume analyses replicated past findings of enlargement in BSD, but did not detect abnormalities in the high‐risk group. Examination of subnuclei volumes detected differences in volume between the high‐risk and BSD groups that were missed in the whole amygdala volume. Results have implications for understanding amygdala abnormalities among individuals with, and at risk for, a BSD.

中文翻译：

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双相谱系障碍中的杏仁核亚核体积：来自基于扩散的子分割和高风险设计的见解。

杏仁核异常在双相谱系障碍 (BSD) 中被广泛记录。杏仁核体积通常在 BSD 发作后测量；因此，尚不清楚杏仁核异常是否预示 BSD 风险或与该疾病有关。此外，过去的文献通常将杏仁核视为同质结构，并没有考虑其独特的亚核及其与其他大脑区域的不同连接。为了解决这些问题，我们使用行为高风险设计和基于扩散的细分来检查患有 BSD 和有患 BSD 风险的无药物个体的杏仁核亚核。行为高风险设计 ( N = 114) 包括低风险 ( N = 37)、高风险 ( N = 47) 和 BSD 组 ( N= 30）。对杏仁核进行了基于扩散的细分，以确定杏仁核体积的差异是否与特定的亚核有关。与低风险个体相比，具有 BSD 诊断的个体表现出更大的整体双侧杏仁核体积。亚核的检查显示，与高风险组相比，BSD 组在左侧内侧和中央亚核中的体积更大，与低风险组相比，右侧亚核的体积更大。在 BSD 组中，特定的杏仁核亚核体积与自第一次发作以来的时间和终生发作次数有关。总之，整个杏仁核体积分析重复了过去 BSD 扩大的发现，但没有检测到高危组的异常。检查亚核体积检测到高风险组和 BSD 组之间的体积差异，这些差异在整个杏仁核体积中被遗漏。结果对了解患有 BSD 和有患 BSD 风险的个体的杏仁核异常具有重要意义。