Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467
Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467.
J Neurosci. 2019 Apr 17;39(16):3130-3143. doi: 10.1523/JNEUROSCI.2834-18.2019. Epub 2019 Feb 13.
The amygdala is well documented as the critical nexus of emotionally enhanced memory, yet its role in the creation of negative memory biases, better memory for negative compared with positive stimuli, has not been clarified. Although prior work suggests valence-specific effects at the moment of "online" encoding and retrieval, with enhanced visuosensory processes supporting negative memories in particular, here we tested the novel hypothesis that the amygdala engages with distant cortical regions after encoding in a manner that predicts inter-individual differences in negative memory biases in humans. Twenty-nine young adults (males and females) were scanned while they incidentally encoded negative, neutral, and positive scenes, each preceded by a line-drawing sketch of the scene. Twenty-four hours later, participants were scanned during an Old/New recognition memory task with only the line-drawings presented as retrieval cues. We replicated and extended our prior work, showing that enhanced online visuosensory recapitulation supports negative memory. Critically, resting-state scans flanked the encoding task, allowing us to show for the first time that individual differences in "off-line" increases in amygdala resting-state functional connectivity (RSFC) immediately following encoding relate to negative and positive memory bias at test. Specifically, post-encoding increases in amygdala RSFC with visuosensory and frontal regions were associated with the degree of negative and positive memory bias, respectively. These findings provide new evidence that valence-specific negative memory biases can be linked to the way that sensory processes are integrated into amygdala-centered emotional memory networks. Decades of research has placed the amygdala at the center of the emotional memory network. Despite the clinical importance of disproportionate memory for negative compared with positive events, it is not known whether post-encoding increases in amygdala-cortical coupling, possibly reflective of early consolidation processes, bear any influence on the degree or direction of such emotional memory biases. We demonstrate that, across participants, increases in post-encoding amygdala coupling with visuosensory and frontal regions are associated with more pronounced negative and positive memory biases, respectively. These findings provide the first evidence linking post-encoding amygdala modulation to the degree of negative or positive memory bias, emphasizing the need for valence-based accounts of the amygdala's role in emotional memory.
杏仁核是情绪增强记忆的关键枢纽，这一点已得到充分证明，然而，它在产生负面记忆偏差（即与积极刺激相比，对负面刺激的记忆更好）方面的作用尚未得到明确。尽管之前的研究表明，在“在线”编码和检索的时刻，效价特异性效应存在，特别是增强了视觉感官过程对负面记忆的支持，但在这里，我们提出了一个新的假设，即在编码后，杏仁核与远距离皮质区域相互作用，从而预测人类负面记忆偏差的个体差异。29 名年轻成年人（男性和女性）在偶然编码负面、中性和正面场景时接受扫描，每个场景都先由场景的线描草图呈现。24 小时后，参与者在仅呈现线描草图作为检索线索的旧/新识别记忆任务中接受扫描。我们复制并扩展了之前的工作，表明在线增强的视觉感官再现支持负面记忆。关键的是，静息态扫描位于编码任务的两侧，使我们能够首次表明，编码后静息态杏仁核功能连接（RSFC）的个体差异与测试时的负面和正面记忆偏差相关。具体来说，编码后与视觉和额区的杏仁核 RSFC 增加与负面和正面记忆偏差的程度分别相关。这些发现提供了新的证据，表明效价特异性的负面记忆偏差可以与将感觉过程整合到以杏仁核为中心的情绪记忆网络的方式联系起来。几十年来的研究将杏仁核置于情绪记忆网络的中心。尽管与积极事件相比，对负面事件的不成比例记忆具有临床重要性，但尚不清楚编码后杏仁核-皮质耦合的增加是否对这种情绪记忆偏差的程度或方向有任何影响，可能反映了早期巩固过程。我们证明，在参与者中，编码后与视觉感官和额区的杏仁核耦合增加分别与更明显的负面和正面记忆偏差相关。这些发现为将编码后杏仁核调节与负面或正面记忆偏差的程度联系起来提供了第一个证据，强调了基于效价的杏仁核在情绪记忆中的作用的解释的必要性。
