🤖 AI Summary
This work addresses the challenge of efficiently decoding temporal information in event-based time-series data with traditional feedforward spiking neural networks, which often rely on recurrent or delay mechanisms at the cost of hardware efficiency. Inspired by biological dendritic sequence detection, the authors propose DendroNN—a dendrite-centric network that treats input spike trains as spatiotemporal features and employs a gradient-free rewiring training strategy. Key innovations include the first computationally tractable model embodying dendritic sequence detection capability, an event-driven temporal wheel mechanism, and an asynchronous digital hardware architecture that integrates dynamic and static sparsity with intrinsic quantization. Evaluated across multiple event-based datasets, DendroNN achieves state-of-the-art accuracy and demonstrates up to a 4× improvement in energy efficiency over existing neuromorphic hardware on audio classification tasks.
📝 Abstract
Spatiotemporal information is at the core of diverse sensory processing and computational tasks. Feed-forward spiking neural networks can be used to solve these tasks while offering potential benefits in terms of energy efficiency by computing event-based. However, they have trouble decoding temporal information with high accuracy. Thus, they commonly resort to recurrence or delays to enhance their temporal computing ability which, however, bring downsides in terms of hardware-efficiency. In the brain, dendrites are computational powerhouses that just recently started to be acknowledged in such machine learning systems. In this work, we focus on a sequence detection mechanism present in branches of dendrites and translate it into a novel type of neural network by introducing a dendrocentric neural network, DendroNN. DendroNNs identify unique incoming spike sequences as spatiotemporal features. This work further introduces a rewiring phase to train the non-differentiable spike sequences without the use of gradients. During the rewiring, the network memorizes frequently occurring sequences and additionally discards those that do not contribute any discriminative information. The networks display competitive accuracies across various event-based time series datasets. We also propose an asynchronous digital hardware architecture using a time-wheel mechanism that builds on the event-driven design of DendroNNs, eliminating per-step global updates typical of delay- or recurrence-based models. By leveraging a DendroNN's dynamic and static sparsity along with intrinsic quantization, it achieves up to 4x higher efficiency than state-of-the-art neuromorphic hardware at comparable accuracy on the same audio classification task, demonstrating its suitability for spatiotemporal event-based computing. This work offers a novel approach to low-power spatiotemporal processing on event-driven hardware.