Fitting summary statistics of neural data with a differentiable spiking network simulator

Guillaume Bellec, Shuqi Wang, Alireza Modirshanechi, Johanni Brea, Wulfram Gerstner

Keywords: fitting, spikes, MLE, likelihood, GLM, spiking, recurrent, RNN, RSNN, neural data, surrogate gradients, straight through, Bayesian, prior, statistics, binary networks

TL;DR: We fit a recurrent network model to recorded neural activity statistics using back-propagation in spiking networks.

Abstract: Fitting network models to neural activity is an important tool in neuroscience. A popular approach is to model a brain area with a probabilistic recurrent spiking network whose parameters maximize the likelihood of the recorded activity. Although this is widely used, we show that the resulting model does not produce realistic neural activity. To correct for this, we suggest to augment the log-likelihood with terms that measure the dissimilarity between simulated and recorded activity. This dissimilarity is defined via summary statistics commonly used in neuroscience and the optimization is efficient because it relies on back-propagation through the stochastically simulated spike trains. We analyze this method theoretically and show empirically that it generates more realistic activity statistics. We find that it improves upon other fitting algorithms for spiking network models like GLMs (Generalized Linear Models) which do not usually rely on back-propagation. This new fitting algorithm also enables the consideration of hidden neurons which is otherwise notoriously hard, and we show that it can be crucial when trying to infer the network connectivity from spike recordings.

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Code: https://github.com/EPFL-LCN/pub-bellec-wang-2021-sample-and-measure