Ongoing studies have identified similarities between neural representations in biological networks and in deep artificial neural networks. This has led to renewed interest in developing analogies between the backpropagation learning algorithm used to train artificial networks and the synaptic plasticity rules operative in the brain. These efforts are challenged by biologically implausible features of backpropagation, one of which is a reliance on symmetric forward and backward synaptic weights. A number of methods have been proposed that do not rely on weight symmetry but, thus far, these have failed to scale to deep convolutional networks and complex data. We identify principal obstacles to the scalability of such algorithms and introduce several techniques to mitigate them. We demonstrate that a modification of the feedback alignment method that enforces a weaker form of weight symmetry, one that requires agreement of weight sign but not magnitude, can achieve performance competitive with backpropagation. Our results complement those of Bartunov et al. (2018) and Xiao et al. (2018b) and suggest that mechanisms that promote alignment of feedforward and feedback weights are critical for learning in deep networks.

研究深度人工神经网络中的反向传播学习算法与大脑神经元突触可塑性规律的类比，介绍了不依赖于对称前向和后向突触权重的算法，提出通过加强权重符号一致性的反馈对准法的修改，可以实现与反向传播法相当的性能。这些研究结果表明，促进前向和反馈权重对准的机制对于深度网络的学习是至关重要的。

深度卷积网络中的反馈对齐