Department of Psychology, Center for Brain, Biology, and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA.
Department of Psychology, Center for Brain, Biology, and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA.
Neurobiol Aging. 2021 Oct;106:232-240. doi: 10.1016/j.neurobiolaging.2021.06.015. Epub 2021 Jun 22.
Older compared to younger adults show greater amygdala activity to positive emotions, and are more likely to interpret emotionally ambiguous stimuli (e.g., surprised faces) as positive. While some evidence suggests this positivity effect results from a top-down, effortful mechanism, others suggest it may emerge as the default or initial response. The amygdala is a key node in rapid, bottom-up processing and patterns of amygdala activity over time (e.g., habituation) can shed light on the mechanisms underlying the positivity effect. Younger and older adults passively viewed neutral and surprised faces in an MRI. Only in older adults, amygdala habituation was associated with the tendency to interpret surprised faces as positive or negative (valence bias), where a more positive bias was associated with greater habituation. Interestingly, although a positive bias in younger adults was associated with slower responses, consistent with an initial negativity hypothesis in younger adults, older adults showed faster categorizations of positivity. Together, we propose that there may be a switch to a primacy of positivity in aging.
与年轻人相比，老年人对积极情绪的杏仁核活动更大，并且更有可能将情感上模棱两可的刺激（例如惊讶的面孔）解释为积极的。虽然有一些证据表明这种积极性效应是自上而下的、费力的机制的结果，但也有一些证据表明它可能是默认或初始反应。杏仁核是快速、自下而上处理的关键节点，随着时间的推移（例如，习惯化），杏仁核活动模式可以揭示积极性效应的机制。年轻人和老年人在 MRI 中被动观看中性和惊讶的面孔。只有在老年人中，杏仁核习惯化与将惊讶的面孔解释为积极或消极（效价偏差）的趋势相关，其中更积极的偏差与更大的习惯化相关。有趣的是，尽管年轻人的积极偏差与较慢的反应相关，与年轻人最初的消极假设一致，但老年人对积极性的分类更快。总的来说，我们提出，在衰老过程中，可能会出现一种对积极性的优先考虑的转变。
