Madarasz Tamas J, Diaz-Mataix Lorenzo, Akhand Omar, Ycu Edgar A, LeDoux Joseph E, Johansen Joshua P
Center for Neural Science, New York University, New York, New York, USA.
RIKEN Brain Science Institute, Wako, Saitama, Japan.
Nat Neurosci. 2016 Jul;19(7):965-72. doi: 10.1038/nn.4308. Epub 2016 May 23.
Recognizing predictive relationships is critical for survival, but an understanding of the underlying neural mechanisms remains elusive. In particular, it is unclear how the brain distinguishes predictive relationships from spurious ones when evidence about a relationship is ambiguous, or how it computes predictions given such uncertainty. To better understand this process, we introduced ambiguity into an associative learning task by presenting aversive outcomes both in the presence and in the absence of a predictive cue. Electrophysiological and optogenetic approaches revealed that amygdala neurons directly regulated and tracked the effects of ambiguity on learning. Contrary to established accounts of associative learning, however, interference from competing associations was not required to assess an ambiguous cue-outcome contingency. Instead, animals' behavior was explained by a normative account that evaluates different models of the environment's statistical structure. These findings suggest an alternative view of amygdala circuits in resolving ambiguity during aversive learning.
识别预测关系对生存至关重要，但对其潜在神经机制的理解仍然难以捉摸。特别是，当关于一种关系的证据不明确时，大脑如何将预测关系与虚假关系区分开来，或者在这种不确定性下它如何计算预测，尚不清楚。为了更好地理解这一过程，我们通过在有预测线索和没有预测线索的情况下都呈现厌恶结果，将模糊性引入到一个联想学习任务中。电生理和光遗传学方法表明，杏仁核神经元直接调节并跟踪模糊性对学习的影响。然而，与既定的联想学习观点相反，评估模糊的线索-结果偶然性并不需要来自竞争联想的干扰。相反，动物的行为可以用一种规范性解释来解释，这种解释评估环境统计结构的不同模型。这些发现为杏仁核回路在厌恶学习过程中解决模糊性提供了另一种观点。
