Dopamine-associated cached values are not sufficient as the basis for action selection
Dopamine-associated cached values are not sufficient as the basis for action selection
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DOI：
10.1073/pnas.1419770111
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发表时间：
2014-12-23
影响因子：
11.1
通讯作者：
Phillips, Paul E. M.
中科院分区：
文献类型：
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作者：
Hollon, Nick G.;Arnold, Monica M.;Phillips, Paul E. M.
时相性多巴胺传递被认为是一个关键的教学信号，它更新分配给奖励预测刺激和行动的存储(或“缓存”)值。人们普遍假设，这些缓存的值决定了在多个行动方案中的选择，这一前提为当代决策理论提供了基础。在目前的工作中，我们使用快速扫描循环伏安法从线索诱发的大鼠伏隔核多巴胺释放中探测与多巴胺相关的缓存值，执行成本效益决策范式，以批判性地评估与多巴胺相关的缓存值与偏好之间的关系。通过操纵获得不同大小奖励所需的努力量，我们能够使老鼠在某些阶段倾向于选择产生高价值回报的选项，而在另一些阶段倾向于倾向于产生低价值回报的选项。因此，这种方法允许在奖励大小和主观偏好分离的情况下调查与多巴胺相关的缓存值。我们观察到，即使当大鼠更喜欢产生低价值奖励的选项时，线索诱发的中脑边缘多巴胺对产生高价值奖励的选项的释放也更多。这一结果确定了可用选项的顺序效用与其缓存值的排序之间明显的不匹配，从而提供了强有力的证据，表明与多巴胺相关的缓存值不能成为简单经济决策中选择的唯一决定因素。
Phasic dopamine transmission is posited to act as a critical teaching signal that updates the stored (or "cached") values assigned to reward-predictive stimuli and actions. It is widely hypothesized that these cached values determine the selection among multiple courses of action, a premise that has provided a foundation for contemporary theories of decision making. In the current work we used fast-scan cyclic voltammetry to probe dopamine-associated cached values from cue-evoked dopamine release in the nucleus accumbens of rats performing cost-benefit decision-making paradigms to evaluate critically the relationship between dopamine-associated cached values and preferences. By manipulating the amount of effort required to obtain rewards of different sizes, we were able to bias rats toward preferring an option yielding a high-value reward in some sessions and toward instead preferring an option yielding a low-value reward in others. Therefore, this approach permitted the investigation of dopamine-associated cached values in a context in which reward magnitude and subjective preference were dissociated. We observed greater cue-evoked mesolimbic dopamine release to options yielding the high-value reward even when rats preferred the option yielding the low-value reward. This result identifies a clear mismatch between the ordinal utility of the available options and the rank ordering of their cached values, thereby providing robust evidence that dopamine-associated cached values cannot be the sole determinant of choices in simple economic decision making.