The Backpropagation Algorithm Implemented on Spiking Neuromorphic Hardware

The capabilities of natural neural systems have inspired new generations of machine learning algorithms as well as neuromorphic very large-scale integrated (VLSI) circuits capable of fast, low-power information processing. However, most modern machine learning algorithms are not neurophysiologically plausible and thus are not directly implementable in neuromorphic hardware. In particular, the workhorse of modern deep learning, the backpropagation algorithm, has proven difficult to translate to neuromorphic hardware. In this study, we present a neuromorphic, spiking backpropagation algorithm based on pulse-gated dynamical information coordination and processing, implemented on Intel's Loihi neuromorphic research processor. We demonstrate a proof-of-principle three-layer circuit that learns to classify digits from the MNIST dataset. This implementation shows a path for using massively parallel, low-power, low-latency neuromorphic processors in modern deep learning applications.