Berridge Kent C, Aldridge J Wayne
University of Michigan.
Soc Cogn. 2008 Oct 1;26(5):621-646. doi: 10.1521/soco.2008.26.5.621.
How do brain representations of the utility of a hedonic goal guide decisions about whether to pursue it? Our focus here will be on brain mechanisms of reward utility operating at particular decision moments in life. Moments such as when you encounter an image, sound, scent or other cue associated in your past with a particular reward; or perhaps just vividly imagine that cue. Such a cue can often trigger a sudden motivational urge to pursue that goal, and sometimes a decision to do so. In drug addicts trying to quit, a cue for the addicted drug might trigger urges that rise to compulsive levels of intensity, despite prior commitments to abstain, leading to the decision to relapse into taking the drug again. Normal or addicted, the urge and decision may well have been lacking immediately before the cue was encountered. The decision to pursue the cued reward might never have happened if the cue had not been encountered. Why can such cues momentarily dominate decision making? The answer involves brain mesolimbic dopamine mechanisms that amplify the incentive salience of reward cues, selectively elevating decision utility to trigger "wanting" for the goal. We describe affective neuroscience studies of brain limbic generators of "wanting" that shed light on how cues trigger pursuit of their goals, both normally and even under intense conditions of irrational goal pursuit.
享乐目标的效用在大脑中的表征是如何指导关于是否追求该目标的决策的?我们这里关注的将是在人生特定决策时刻起作用的奖励效用的大脑机制。比如当你遇到一个在你过去与特定奖励相关联的图像、声音、气味或其他线索时;或者也许只是生动地想象那个线索。这样一个线索常常能引发追求那个目标的突然的动机冲动,有时还会引发这样做的决定。在试图戒毒的吸毒者中,与成瘾药物相关的线索可能会引发强烈到强迫程度的冲动,尽管之前有过戒毒的承诺,导致再次吸毒的复吸决定。无论是正常情况还是成瘾状态,在遇到线索之前可能都不存在这种冲动和决定。如果没有遇到线索,追求线索提示的奖励的决定可能永远不会发生。为什么这样的线索能瞬间主导决策呢?答案涉及大脑中脑边缘多巴胺机制,该机制会增强奖励线索的激励显著性,选择性地提高决策效用以触发对目标的“渴望”。我们描述了关于大脑边缘系统产生“渴望”的情感神经科学研究,这些研究揭示了线索是如何在正常情况下以及甚至在非理性目标追求的强烈条件下触发对其目标的追求的。