Nucleus accumbens core dopamine signaling tracks the need-based motivational value of food-paired cues.
Nucleus accumbens core dopamine signaling tracks the need-based motivational value of food-paired cues.
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DOI：
10.1111/jnc.13494
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发表时间：
2016-03
影响因子：
4.7
通讯作者：
Wassum KM
中科院分区：
文献类型：
--
作者：
Aitken TJ;Greenfield VY;Wassum KM
环境奖励预测刺激提供了工具性奖励寻求活动的主要动机来源，这与伏隔核（NAc）中的多巴胺信号有关。这种线索诱导的激励动机可以是非常普遍的，不局限于获得相同独特奖励的工具性行为，也通常受到当前需求状态的调节，因此线索只有在适应性的情况下才会激发行为。但线索诱发的多巴胺信号是否同样受到需求状态的调节尚不清楚。在这里，我们使用快速扫描循环伏安法来监测大鼠在巴甫洛夫-工具转移（PIT）任务期间NAc核心的多巴胺浓度变化，在该任务中，在饥饿和饱腹状态下评估两种线索的激励影响，每一种线索都表示一种不同的食物奖励（蔗糖或食物颗粒），而另一种行为则获得第三种独特的食物奖励（葡萄味多糖）。当饥饿时，这两种线索都会引发强烈的NAc多巴胺反应。蔗糖线索诱发的多巴胺反应的强度与这种刺激选择性诱导的PIT效应相关。饱腹感减弱了这些线索诱发的多巴胺反应和行为反应，即使老鼠在这种状态下从未经历过特定的食物奖励。这些数据表明，提示诱发的NAc核心反应对当前需求状态敏感，而当前需求状态是决定提示动机行为当前适应性效用的关键变量。
Environmental reward-predictive stimuli provide a major source of motivation for instrumental reward-seeking activity and this has been linked to dopamine signaling in the nucleus accumbens (NAc). This cue-induced incentive motivation can be quite general, not restricted to instrumental actions that earn the same unique reward, and is also typically regulated by one’s current need state, such that cues only motivate actions when this is adaptive. But it is unknown whether cue-evoked dopamine signaling is similarly regulated by need state. Here we used fast-scan cyclic voltammetry to monitor dopamine concentration changes in the NAc core of rats during a Pavlovian-to-instrumental transfer (PIT) task in which the motivating influence of two cues, each signaling a distinct food reward (sucrose or food pellets), over an action earning a third unique food reward (grape-flavored polycose) was assessed in a state of hunger and of satiety. Both cues elicited a robust NAc dopamine response when hungry. The magnitude of the sucrose cue-evoked dopamine response correlated with the PIT effect that was selectively induced by this stimulus. Satiety attenuated these cue-evoked dopamine responses and behavioral responding, even though rats had never experienced the specific food rewards in this state. These data demonstrate that cue-evoked NAc core responses are sensitive to current need state, one critical variable that determines the current adaptive utility of cue-motivated behavior.