Division of Humanities and Social Sciences, MC 228-77, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, 91125, USA.
Computation and Neural Systems Program, MC 228-77, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, 91125, USA.
Nat Commun. 2019 Mar 7;10(1):1099. doi: 10.1038/s41467-019-08922-7.
Prominent accounts of Pavlovian conditioning successfully approximate the frequency and intensity of conditioned responses under the assumption that learning is exclusively model-free; that animals do not develop a cognitive map of events. However, these model-free approximations fall short of comprehensively capturing learning and behavior in Pavlovian conditioning. We therefore performed multivoxel pattern analysis of high-resolution functional MRI data in human participants to test for the encoding of stimulus-stimulus associations that could support model-based computations during Pavlovian conditioning. We found that dissociable sub-regions of the striatum encode predictions of stimulus-stimulus associations and predictive value, in a manner that is directly related to learning performance. Activity patterns in the orbitofrontal cortex were also found to be related to stimulus-stimulus as well as value encoding. These results suggest that the brain encodes model-based representations during Pavlovian conditioning, and that these representations are utilized in the service of behavior.
经典条件作用的突出描述成功地模拟了条件反应的频率和强度，假设学习是完全无模型的；也就是说，动物不会对事件形成认知地图。然而，这些无模型的近似方法并不能全面捕捉到经典条件作用中的学习和行为。因此，我们对人类参与者的高分辨率功能磁共振成像数据进行了多体素模式分析，以测试在经典条件作用中支持基于模型计算的刺激-刺激关联的编码。我们发现，纹状体的可分离亚区以与学习表现直接相关的方式编码刺激-刺激关联和预测价值的预测。眶额皮层的活动模式也被发现与刺激-刺激以及价值编码有关。这些结果表明，大脑在经典条件作用过程中编码基于模型的表示，并且这些表示被用于行为服务。
