Schwiedrzik Caspar M, Freiwald Winrich A
Laboratory of Neural Systems, The Rockefeller University, New York, NY 10065, USA; Neural Circuits and Cognition Lab, European Neuroscience Institute, 37077 Göttingen, Germany; University Medical Center Goettingen, 37075 Göttingen, Germany; Cognitive Neuroscience Laboratory, German Primate Center, 37077 Göttingen, Germany.
Laboratory of Neural Systems, The Rockefeller University, New York, NY 10065, USA.
Neuron. 2017 Sep 27;96(1):89-97.e4. doi: 10.1016/j.neuron.2017.09.007.
Theories like predictive coding propose that lower-order brain areas compare their inputs to predictions derived from higher-order representations and signal their deviation as a prediction error. Here, we investigate whether the macaque face-processing system, a three-level hierarchy in the ventral stream, employs such a coding strategy. We show that after statistical learning of specific face sequences, the lower-level face area ML computes the deviation of actual from predicted stimuli. But these signals do not reflect the tuning characteristic of ML. Rather, they exhibit identity specificity and view invariance, the tuning properties of higher-level face areas AL and AM. Thus, learning appears to endow lower-level areas with the capability to test predictions at a higher level of abstraction than what is afforded by the feedforward sweep. These results provide evidence for computational architectures like predictive coding and suggest a new quality of functional organization of information-processing hierarchies beyond pure feedforward schemes.
像预测编码这样的理论提出,低阶脑区会将其输入与从高阶表征得出的预测进行比较,并将它们的偏差作为预测误差发出信号。在此,我们研究猕猴面部处理系统(腹侧流中的一个三级层次结构)是否采用了这样一种编码策略。我们表明,在对特定面部序列进行统计学习后,较低层级的面部区域ML会计算实际刺激与预测刺激之间的偏差。但这些信号并不反映ML的调谐特性。相反,它们表现出身份特异性和视角不变性,即较高层级面部区域AL和AM的调谐属性。因此,学习似乎赋予了低层级区域在比前馈扫描所提供的更高抽象层次上测试预测的能力。这些结果为像预测编码这样的计算架构提供了证据,并暗示了超越纯前馈方案的信息处理层次结构功能组织的一种新特性。