Towards the Training of Deeper Predictive Coding Neural Networks

Fuente: arXiv
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Main Authors: Qi, Chang, Forasassi, Matteo, Lukasiewicz, Thomas, Salvatori, Tommaso
Format: Preprint
Published: 2025
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author Qi, Chang
Forasassi, Matteo
Lukasiewicz, Thomas
Salvatori, Tommaso
author_facet Qi, Chang
Forasassi, Matteo
Lukasiewicz, Thomas
Salvatori, Tommaso
contents Predictive coding networks are neural models that perform inference through an iterative energy minimization process, whose operations are local in space and time. While effective in shallow architectures, they suffer significant performance degradation beyond five to seven layers. In this work, we show that this degradation is caused by exponentially imbalanced errors between layers during weight updates, and by predictions from the previous layers not being effective in guiding updates in deeper layers. Furthermore, when training models with skip connections, the energy propagated by the residuals reaches higher layers faster than that propagated by the main pathway, affecting test accuracy. We address the first issue by introducing a novel precision-weighted optimization of latent variables that balances error distributions during the relaxation phase, the second issue by proposing a novel weight update mechanism that reduces error accumulation in deeper layers, and the third one by using auxiliary neurons that slow down the propagation of the energy in the residual connections. Empirically, our methods achieve performance comparable to backpropagation on deep models such as ResNets, opening new possibilities for predictive coding in complex tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2506_23800
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Towards the Training of Deeper Predictive Coding Neural Networks
Qi, Chang
Forasassi, Matteo
Lukasiewicz, Thomas
Salvatori, Tommaso
Machine Learning
Predictive coding networks are neural models that perform inference through an iterative energy minimization process, whose operations are local in space and time. While effective in shallow architectures, they suffer significant performance degradation beyond five to seven layers. In this work, we show that this degradation is caused by exponentially imbalanced errors between layers during weight updates, and by predictions from the previous layers not being effective in guiding updates in deeper layers. Furthermore, when training models with skip connections, the energy propagated by the residuals reaches higher layers faster than that propagated by the main pathway, affecting test accuracy. We address the first issue by introducing a novel precision-weighted optimization of latent variables that balances error distributions during the relaxation phase, the second issue by proposing a novel weight update mechanism that reduces error accumulation in deeper layers, and the third one by using auxiliary neurons that slow down the propagation of the energy in the residual connections. Empirically, our methods achieve performance comparable to backpropagation on deep models such as ResNets, opening new possibilities for predictive coding in complex tasks.
title Towards the Training of Deeper Predictive Coding Neural Networks
topic Machine Learning
url https://arxiv.org/abs/2506.23800