Department of Psychiatry, University of Michigan, Ann Arbor, Michigan 48109, USA.
J Neurosci. 2010 Jun 9;30(23):8032-41. doi: 10.1523/JNEUROSCI.4729-09.2010.
Some decisions are made after obtaining several pieces of information, whereas others are reached quickly. Such differences may depend on the quality of information acquired, as well as individual variability in how cautiously evidence is evaluated. The current study examined neural activity while subjects accumulated sequential pieces of evidence and then made a decision. Uncertainty was updated with each piece of evidence, with individual ratings of subjective uncertainty characterizing underconfidence when observing evidence. Increased uncertainty during evidence accumulation was associated with activity in dorsal anterior cingulate cortex, whereas greater uncertainty when executing a decision uniquely elicited lateral frontal and parietal activity. Greater underconfidence when observing evidence correlated with activity in ventromedial prefrontal cortex. These results suggest that neural mechanisms of uncertainty depend on the stage of decision-making (belief updating vs decision) and that greater subjective uncertainty when evaluating evidence is associated with activity in ventromedial brain regions, even in the absence of overt risk.
有些决策是在获取了若干信息之后做出的，而另一些决策则是快速做出的。这种差异可能取决于所获得信息的质量，以及个体在评估证据时谨慎程度的差异。本研究在受试者积累顺序信息然后做出决策的过程中，监测了大脑的活动。随着每一条信息的更新，对主观不确定性的个体评分会导致在观察证据时的不自信，即置信不足。在证据积累过程中，不确定性的增加与背侧前扣带皮层的活动有关，而在做出决策时不确定性的增加则会独特地引起额侧和顶侧的前额叶和顶叶活动。在观察证据时更大的置信不足与腹内侧前额叶皮层的活动有关。这些结果表明，不确定性的神经机制取决于决策阶段（信念更新与决策），在评估证据时更大的主观不确定性与腹侧脑区的活动有关，即使在没有明显风险的情况下也是如此。
