Lambert Hilary K, Sheridan Margaret A, Sambrook Kelly A, Rosen Maya L, Askren Mary K, McLaughlin Katie A
Department of Psychology, University of Washington, Seattle, Washington 98105.
Department of Psychology, University of North Carolina, Chapel Hill, North Carolina 27599, and.
J Neurosci. 2017 Feb 15;37(7):1925-1934. doi: 10.1523/JNEUROSCI.2618-16.2017. Epub 2017 Jan 16.
Context can drastically influence responses to environmental stimuli. For example, a gunshot should provoke a different response at a public park than a shooting range. Little is known about how contextual processing and neural correlates change across human development or about individual differences related to early environmental experiences. Children ( = 60; 8-19 years, 24 exposed to interpersonal violence) completed a context encoding task during fMRI scanning using a delayed match-to-sample design with neutral, happy, and angry facial cues embedded in realistic background scenes. Outside the scanner, participants completed a memory test for context-face pairings. Context memory and neural correlates of context encoding did not vary with age. Larger hippocampal volume was associated with better context memory. Posterior hippocampus was recruited during context encoding, and greater activation in this region predicted better memory for contexts paired with angry faces. Children exposed to violence had poor memory of contexts paired with angry faces, reduced hippocampal volume, and atypical neural recruitment on encoding trials with angry faces, including reduced hippocampal activation and greater functional connectivity between hippocampus and ventrolateral prefrontal cortex (vlPFC). Greater hippocampus-vlPFC connectivity was associated with worse memory for contexts paired with angry faces. Posterior hippocampus appears to support context encoding, a process that does not exhibit age-related variation from middle childhood to late adolescence. Exposure to dangerous environments in childhood is associated with poor context encoding in the presence of threat, likely due to greater vlPFC-dependent attentional narrowing on threat cues at the expense of hippocampus-dependent processing of the broader context. The ability to use context to guide reactions to environmental stimuli promotes flexible behavior. Remarkably little research has examined how contextual processing changes across development or about influences of the early environment. We provide evidence for posterior hippocampus involvement in context encoding in youth and lack of age-related variation from middle childhood to late adolescence. Children exposed to interpersonal violence exhibited poor memory of contexts paired with angry faces and atypical neural recruitment during context encoding in the presence of threatening facial cues. Heightened attention to threat following violence exposure may come at the expense of encoding contextual information, which may ultimately contribute to pathological fear expressed in safe contexts.
情境可极大地影响对环境刺激的反应。例如,在公园听到枪声引发的反应应与射击场不同。对于情境加工和神经关联如何在人类发育过程中发生变化,以及与早期环境经历相关的个体差异,我们所知甚少。儿童(n = 60;8 - 19岁,24人曾遭受人际暴力)在功能磁共振成像扫描期间完成一项情境编码任务,采用延迟样本匹配设计,其中中性、开心和愤怒的面部线索嵌入逼真的背景场景中。在扫描仪外,参与者完成对情境 - 面部配对的记忆测试。情境记忆和情境编码的神经关联并不随年龄而变化。更大的海马体体积与更好的情境记忆相关。在情境编码期间后海马体被激活,该区域更强的激活预示着对与愤怒面孔配对的情境有更好的记忆。遭受暴力的儿童对与愤怒面孔配对的情境记忆较差,海马体体积减小,并且在愤怒面孔的编码试验中神经募集模式异常,包括海马体激活减少以及海马体与腹外侧前额叶皮层(vlPFC)之间功能连接增强。更强的海马体 - vlPFC连接与对与愤怒面孔配对的情境的更差记忆相关。后海马体似乎支持情境编码,这一过程从中童年到青少年晚期并未表现出与年龄相关的变化。童年时期暴露于危险环境与在威胁存在时情境编码不佳有关,可能是由于腹外侧前额叶皮层依赖的对威胁线索的注意力更集中,而牺牲了海马体依赖的对更广泛情境的加工。利用情境来指导对环境刺激的反应的能力促进灵活行为。令人惊讶的是,很少有研究考察情境加工如何在发育过程中变化或早期环境的影响。我们提供了后海马体参与青少年情境编码以及从中童年到青少年晚期缺乏与年龄相关变化的确凿证据。遭受人际暴力的儿童在存在威胁性面部线索的情境编码期间,对与愤怒面孔配对的情境记忆较差且神经募集模式异常。暴力暴露后对威胁的关注度提高可能是以编码情境信息为代价的,这最终可能导致在安全情境中表现出病理性恐惧。