People subconsciously make thousands of tiny predictions each day, e.g., when a bus will arrive, who is knocking on the door or if a dropped glass will break.
Researchers at Washington University in St Louis focused on the mid-brain dopamine system (MDS), which provides signals to the rest of the brain when unexpected events occur.
The scientists tested healthy young volunteers who were shown films of everyday events. And then it was stopped. Participants were then asked to predict what would happen five seconds later.
Half of the time, the movie was stopped just before an event boundary, when a new event was just about to start. The other half of the time, the film was stopped in the middle of an event.
The researchers found that participants were more than 90 percent correct in predicting activity within the event, but less than 80 percent correct in predicting across the event boundary. They were also less confident in their predictions.
Using functional MRI (FMRI), researchers found that this system encodes prediction error when participants made prediction. And they saw significant activity in several mid-brain regions, among them the substantial nigra, which is the part of the brain most affected by Parkinson's disease, and is important for controlling movement and making adaptive decisions.
Lead researcher Jeffrey Zacks said: "Successful predictions are associated with the subjective experience of a smooth stream of consciousness. But a few times a minute, our predictions come out wrong and then we perceive a break in the stream of consciousness."
The research is published in the Journal of Cognitive Neuroscience.


据英国《每日邮报》8月23日报道，人们每天都会在潜意识中做出成百上千个小预测，比如公交什么时候会来，谁在敲门，或者掉落的杯子是否会破碎。

圣路易斯华盛顿大学的研究人员集中研究了中脑多巴胺系统,该系统在意外事件发生时，会向脑部其他区域发送信号。

科学家对一些身体状况良好的年轻志愿者进行测试，并让其观看关于日常生活的影片，然后暂停影片，让他们预测影片中接下来5秒后会发生什么。

（影片暂停的情况分为两种），一种是，影片刚好停在事件的分界线上，即一个新事件开始前。另一种是，影片在某事件的中间部分停止。

研究人员发现，90%以上的参与者可以对事件内的活动做出正确的预测，但是，跨事件做出正确预测的人却不足80%，而参与者在预测的过程中也更不自信。


通过功能核磁共振成像，研究人员发现中脑多巴胺系统在参与者进行预测时，对预测误差进行了编码。他们观测到很多中脑区域会有明显活动，包括大量的黑质。该物质是人脑中受帕金森氏症影响最大的一部分，它对人类控制行为并作出适应性决定至关重要。


领导该研究的杰弗里•扎克斯说："成功的预测与流畅的意识流主观活动有关，但是，当预测出现错误时，我们就会感知到意识流被打断。"


该研究发表在《认知神经科学杂志》上。

• system [´sistəm] n.系统，体系，制度 (初中英语单词)
• healthy [´helθi] a.健康的 (初中英语单词)
• boundary [´baundəri] n.界线，边界 (初中英语单词)
• movement [´mu:vmənt] n.活动；运动；动作 (初中英语单词)
• stream [stri:m] n.河 vi.流出；飘扬 (初中英语单词)
• perceive [pə´si:v] vt.察觉；看出；领悟 (初中英语单词)
• research [ri´sə:tʃ] n.&vi.调查；探究；研究 (初中英语单词)
• journal [´dʒə:nəl] n.日记；日报；杂志 (初中英语单词)
• unexpected [ʌniks´pektid] a.突然的；意外的 (高中英语单词)
• everyday [´evridei] a.每日的，日常的 (高中英语单词)
• predict [pri´dikt] v.预言；预告；预示 (高中英语单词)
• confident [´kɔnfidənt] a.有信心的，自信的 (高中英语单词)
• significant [sig´nifikənt] a.重要的；意义重大的 (高中英语单词)
• substantial [səb´stænʃəl] a.实质的，真的 (高中英语单词)
• consciousness [´kɔnʃəsnis] n.意识；觉悟；知觉 (高中英语单词)
• prediction [pri´dikʃən] n.预告；(气象等)预报 (英语四级单词)
• affected [ə´fektid] a.做作的；假装的 (英语六级单词)