Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Center for Brain Science, Department of Psychology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
Neuron. 2018 May 2;98(3):616-629.e6. doi: 10.1016/j.neuron.2018.03.036. Epub 2018 Apr 12.
Animals make predictions based on currently available information. In natural settings, sensory cues may not reveal complete information, requiring the animal to infer the "hidden state" of the environment. The brain structures important in hidden state inference remain unknown. A previous study showed that midbrain dopamine neurons exhibit distinct response patterns depending on whether reward is delivered in 100% (task 1) or 90% of trials (task 2) in a classical conditioning task. Here we found that inactivation of the medial prefrontal cortex (mPFC) affected dopaminergic signaling in task 2, in which the hidden state must be inferred ("will reward come or not?"), but not in task 1, where the state was known with certainty. Computational modeling suggests that the effects of inactivation are best explained by a circuit in which the mPFC conveys inference over hidden states to the dopamine system. VIDEO ABSTRACT.
动物根据当前可用的信息进行预测。在自然环境中，感官线索可能无法揭示完整的信息，这就要求动物推断环境的“隐藏状态”。对于隐藏状态推断很重要的大脑结构仍然未知。之前的一项研究表明，中脑多巴胺神经元在经典条件反射任务中表现出不同的反应模式，具体取决于奖励是否在 100%（任务 1）或 90%（任务 2）的试验中给出。在这里，我们发现内侧前额叶皮层（mPFC）的失活会影响任务 2中的多巴胺能信号，在任务 2 中必须推断隐藏状态（“奖励会来还是不会来？”），但在任务 1 中不会，因为状态是确定的。计算模型表明，失活的影响可以通过一个电路来最好地解释，该电路将对隐藏状态的推断传递给多巴胺系统。视频摘要。
