Model agnostic signal encoding by leaky integrate and fire, performance and uncertainty

2024-12-17

arXiv.org

AI Summary

This work addresses the performance degradation and evaluation challenges in leaky integrate-and-fire (LIF) time encoding caused by multiple physical uncertainties—namely, leakage parameter variations, spike-timing jitter, and finite-sampling boundary effects. We propose the first model-agnostic LIF encoding framework. Our method introduces the novel concept of *generalized approximate bandwidth*, replacing conventional exact encoding assumptions, and systematically models the coupled interactions among the three uncertainty sources for the first time. We employ the Wasserstein distance to quantify spike train mismatches, thereby establishing a quantitative relationship between encoding performance and uncertainty levels. Based on this analysis, we derive a transferable, bandwidth-driven initialization strategy. Experimental results demonstrate that this strategy significantly enhances the robustness and convergence speed of downstream signal reconstruction algorithms.

Technology Category

Cognitive Modeling & Cognitive Systems: Neural Spike CodingMachine Learning: Calibration & Uncertainty QuantificationReasoning under Uncertainty: Uncertainty Representations

Application Category

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Abstract

Integrate and fire is a resource efficient time-encoding mechanism that summarizes into a signed spike train those time intervals where a signal's charge exceeds a certain threshold. We analyze the IF encoder in terms of a very general notion of approximate bandwidth, which is shared by most commonly-used signal models. This complements results on exact encoding that may be overly adapted to a particular signal model. We take into account, possibly for the first time, the effect of uncertainty in the exact location of the spikes (as may arise by decimation), uncertainty of integration leakage (as may arise in realistic manufacturing), and boundary effects inherent to finite periods of exposure to the measurement device. The analysis is done by means of a concrete bandwidth-based Ansatz that can also be useful to initialize more sophisticated model specific reconstruction algorithms, and uses the earth mover's (Wassertein) distance to measure spike discrepancy.

Problem

• Analyze IF encoder performance under general bandwidth conditions
• Study impact of spike location and leakage uncertainty
• Measure spike discrepancy using earth mover's distance

Innovation

• Leaky integrate and fire encoding
• Bandwidth-based Ansatz analysis
• Earth mover's distance measurement