Hakamata Yuko, Mizukami Shinya, Izawa Shuhei, Moriguchi Yoshiya, Hori Hiroaki, Kim Yoshiharu, Hanakawa Takashi, Inoue Yusuke, Tagaya Hirokuni
Department of Behavioral Medicine, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan; Department of Health Science, Kitasato University School of Allied Health Sciences, Kanagawa, Japan.
Department of Radiological Technology, Kitasato University School of Allied Health Sciences, Kanagawa, Japan.
Biol Psychiatry Cogn Neurosci Neuroimaging. 2020 Mar;5(3):301-310. doi: 10.1016/j.bpsc.2019.11.008. Epub 2019 Nov 27.
The amygdala can enhance emotional memory encoding as well as anxiogenesis via corticotropin-releasing factor neurons. However, the amygdala's explicit role in emotional encoding remains unclarified in humans. We examined how functional connectivity (FC) of amygdala subnuclei affects emotional encoding, considering its mechanism in which anxiety, attention, and cortisol conceivably participate.
A total of 65 healthy humans underwent resting-state functional magnetic resonance imaging scans and saliva collection at 10 points in time over 2 days. FC analysis was performed for basolateral amygdala subnucleus (BLA) and centromedial amygdala subnucleus. We assessed attentional control via an emotional Stroop task and assessed emotional encoding via a facial identification task that examines how strongly a neutral face is memorized when accompanied by an emotional face (fearful, sad, or happy). FC and task performance were compared between high-anxious and non-high-anxious groups classified by anxious personality scores.
BLA connected with subgenual anterior cingulate cortex (sgACC) in proportion to the strength of fear-related encoding, whereas centromedial subnucleus connected with caudate nucleus for happy-related encoding. The high-anxious group showed more enhanced fear-related encoding but impaired happy-related encoding compared with the non-high-anxious group. BLA-sgACC FC was more intensified in the high-anxious group than in the non-high-anxious group; however, centromedial-caudate FC did not differ between them. Although emotional encoding was uncorrelated with either attentional control or cortisol, BLA-sgACC was positively correlated with cortisol increase after awakening.
The study revealed that neural interactions of BLA, specifically with sgACC, might play a critical role in fear-related memory encoding, depending on the individual's level of anxiety. These findings aid in understanding the complicated mechanisms of emotional memory in anxiety disorders.
杏仁核可通过促肾上腺皮质激素释放因子神经元增强情绪记忆编码以及焦虑症的发生。然而，杏仁核在人类情绪编码中的明确作用仍未阐明。我们研究了杏仁核亚核的功能连接（FC）如何影响情绪编码，并考虑了焦虑、注意力和皮质醇可能参与的机制。
共有65名健康人在2天内的10个时间点接受静息态功能磁共振成像扫描和唾液采集。对基底外侧杏仁核亚核（BLA）和中央内侧杏仁核亚核进行FC分析。我们通过情绪Stroop任务评估注意力控制，并通过面部识别任务评估情绪编码，该任务考察当一张中性面孔与一张情绪面孔（恐惧、悲伤或快乐）同时出现时，中性面孔被记忆的强烈程度。比较高焦虑组和非高焦虑组（根据焦虑人格得分分类）之间的FC和任务表现。
BLA与膝下前扣带回皮质（sgACC）的连接与恐惧相关编码的强度成比例，而中央内侧亚核与尾状核的连接与快乐相关编码有关。与非高焦虑组相比，高焦虑组表现出更强的恐惧相关编码，但快乐相关编码受损。高焦虑组的BLA-sgACC FC比非高焦虑组更强；然而，中央内侧-尾状核FC在两组之间没有差异。尽管情绪编码与注意力控制或皮质醇均无相关性，但BLA-sgACC与觉醒后皮质醇的增加呈正相关。
该研究表明，BLA的神经相互作用，特别是与sgACC的相互作用，可能在与恐惧相关的记忆编码中起关键作用，这取决于个体的焦虑水平。这些发现有助于理解焦虑症中情绪记忆的复杂机制。
