arXiv Machine Learning

Polyhedral Geometry of Time-to-First-Spike Neural Networks

The paper investigates the expressivity of time-to-first-spike spiking neural networks, showing that each neuron's firing time can be represented in a maxout-like form with many constrained affine pieces. It formalizes causal regions as polyhedral sets defined by fixed causal spike sequences and derives bounds on the number of such regions for both shallow and multilayer networks. Experiments confirm that spiking networks can produce richer input-space partitions than conventional feedforward ReLU networks.

arXiv AI
Sep 16

Equivalence of approximation by networks of single- and multi-spike neurons

The paper demonstrates that for a broad class of spiking neuron models, including the leaky integrate‑and‑fire with subtractive reset, any approximation bound proven for multi‑spike networks can be translated to an equivalent single‑spike network with only a linear change in neuron count, and vice versa. This establishes that single‑spike and multi‑spike neural networks possess identical approximation capabilities for general machine learning tasks. Consequently, existing approximation results for single‑spike networks automatically extend to the multi‑spike case.

By Dominik Dold, Philipp Christian Petersen
arXiv Machine Learning
Sep 25

On the second-order optimization for spiking neural networks

The paper introduces SpiKFAX, a second‑order optimization technique for Spiking Neural Networks (SNNs) that uses a Kronecker‑factored approximation of the Fisher information matrix tailored to the sparse, discrete, and temporally recurrent dynamics of SNNs. By addressing the sharp loss landscape that hampers training with conventional optimizers, SpiKFAX improves test accuracy and training stability across five architectures and seven datasets. The method offers a computationally tractable alternative to existing curvature‑based approaches for SNNs.

By Ngoc Phu Doan, Ihsen Alouani
arXiv AI
Oct 12

Convex Optimization of Spiking Neural Networks with Global and Approximation Guarantees

The paper presents a convex formulation for training spiking neural networks (SNNs), showing that the weight‑decay‑regularized training problem for a class of threshold RNNs—including leaky integrate‑and‑fire SNNs—has zero duality gap and matches a convex program’s optimal value. To handle the exponential size of the resulting convex programs, the authors introduce a randomized surrogate with a high‑probability approximation guarantee. Empirical results demonstrate that the convex variant outperforms surrogate‑gradient training on addition and first‑last‑XOR tasks, matches performance on sequential MNIST, and falls slightly behind a reservoir baseline on base‑3 and base‑5 addition.

By Himanshu Udupi, Calvin Ang, Sungyoon Kim, Xiaocong Yang, ChengXiang Zhai
arXiv Computer Vision
Oct 16

The Dormant Spiking Neuron: A State-Driven Mechanism for Efficient Spiking Neural Networks

The paper introduces the Dormant Spiking Neuron (DSN), a state-driven mechanism that allows neurons in spiking neural networks to enter a dormant state when their membrane potential falls below a negative threshold. This dynamic gating prunes redundant computations at the instance level and is trained end‑to‑end via backpropagation through time with surrogate gradients. Experiments on static and neuromorphic datasets, including ImageNet, show that DSN reduces computational energy by 40% to over 70% and improves baseline SNN accuracy by 1.34%, outperforming state‑of‑the‑art static pruning methods.

By Ruichen Ma, Yicai Chen, Pujun Zhou, Yue Zuo, Chongyang Li, Shuang Liu, Shaogang Hu, Guanchao Qiao