From event-based computations to a bio-plausible Spiking Neural Network

Abstract

We propose a neuromimetic online classifier for always-on digit recognition. To achieve this, we extend an existing event-based algorithm which introduced novel spatio-temporal features: time surfaces. Built from asynchronous events acquired by a neuromorphic camera, these time surfaces allow to code the local dynamics of a visual scene and create an efficient hierarchical event-based pattern recognition architecture. Its formalism was previously adapted in the computational neuroscience domain by showing it may be implemented using a Spiking Neural Network (SNN) of leaky integrate-and-fire models and Hebbian learning. Here, we add an online classification layer using a multinomial logistic regression which is compatible with a neural implementation. A decision can be taken at any arbitrary time by taking the $argmax$ of the probability values associated to each class. We extend the parallel with computational neuroscience by demonstrating that this classification layer is also equivalent to a layer of spiking neurons with a Hebbian-like learning mechanism. Our method obtains state-of-the-art performances on the N-MNIST dataset and we show that it is robust to both spatial and temporal jitter. As a summary, we were able to develop a neuromimetic SNN model for online digit classification. We aim at pursuing the study of this architecture for natural scenes and hope to offer insights on the efficiency of neural computations, and in particular how mechanisms of decision-making may be formed.

Publication
Champalimaud Research Symposium (CRS21)
Antoine Grimaldi
Antoine Grimaldi
Phd candidate in Computational Neuroscience

During my PhD, I am focusing on pUltra-fast vision using Spiking Neural Networks.

Victor Boutin
Victor Boutin
Phd in Computational Neuroscience

During my PhD, I focused on predictive coding in bio-inspired neural networks.

Laurent U Perrinet
Laurent U Perrinet
Researcher in Computational Neuroscience

My research interests include Machine Learning and computational neuroscience applied to Vision.

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