Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom.
J Neurosci. 2010 Feb 3;30(5):1721-6. doi: 10.1523/JNEUROSCI.5331-09.2010.
Reward representation in ventral striatum is boosted by perceptual novelty, although the mechanism of this effect remains elusive. Animal studies indicate a functional loop (Lisman and Grace, 2005) that includes hippocampus, ventral striatum, and midbrain as being important in regulating salience attribution within the context of novel stimuli. According to this model, reward responses in ventral striatum or midbrain should be enhanced in the context of novelty even if reward and novelty constitute unrelated, independent events. Using fMRI, we show that trials with reward-predictive cues and subsequent outcomes elicit higher responses in the striatum if preceded by an unrelated novel picture, indicating that reward representation is enhanced in the context of novelty. Notably, this effect was observed solely when reward occurrence, and hence reward-related salience, was low. These findings support a view that contextual novelty enhances neural responses underlying reward representation in the striatum and concur with the effects of novelty processing as predicted by the model of Lisman and Grace (2005).
腹侧纹状体中的奖励表现会因感知新颖性而增强，尽管这种影响的机制仍不清楚。动物研究表明，一个功能循环（Lisman 和 Grace，2005）包括海马体、腹侧纹状体和中脑，对于调节新刺激背景下的突显归因很重要。根据这个模型，即使奖励和新颖性构成不相关的独立事件，在新颖性的背景下，中脑或腹侧纹状体中的奖励反应应该会增强。我们使用 fMRI 表明，如果在无关的新图片之前有奖励预测线索和随后的结果，那么纹状体中的反应会更高，这表明在新颖性的背景下奖励的表现得到了增强。值得注意的是，这种效应仅在奖励发生时观察到，因此奖励相关的突显度较低。这些发现支持了一种观点，即上下文新颖性增强了纹状体中奖励表现的神经反应，与 Lisman 和 Grace（2005）模型预测的新颖性处理的效果一致。
