Coding schemes in neural networks learning classification tasks

Abstract Neural networks posses the crucial ability to generate meaningful representations of task-dependent features. Indeed, with appropriate scaling, supervised learning in neural networks can result in strong, task-dependent feature learning. However, the nature of the emergent representations i...

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Main Authors: Alexander van Meegen, Haim Sompolinsky
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-58276-6
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author Alexander van Meegen
Haim Sompolinsky
author_facet Alexander van Meegen
Haim Sompolinsky
author_sort Alexander van Meegen
collection DOAJ
description Abstract Neural networks posses the crucial ability to generate meaningful representations of task-dependent features. Indeed, with appropriate scaling, supervised learning in neural networks can result in strong, task-dependent feature learning. However, the nature of the emergent representations is still unclear. To understand the effect of learning on representations, we investigate fully-connected, wide neural networks learning classification tasks using the Bayesian framework where learning shapes the posterior distribution of the network weights. Consistent with previous findings, our analysis of the feature learning regime (also known as ‘non-lazy’ regime) shows that the networks acquire strong, data-dependent features, denoted as coding schemes, where neuronal responses to each input are dominated by its class membership. Surprisingly, the nature of the coding schemes depends crucially on the neuronal nonlinearity. In linear networks, an analog coding scheme of the task emerges; in nonlinear networks, strong spontaneous symmetry breaking leads to either redundant or sparse coding schemes. Our findings highlight how network properties such as scaling of weights and neuronal nonlinearity can profoundly influence the emergent representations.
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spelling doaj-art-1dd85e43228c4dd692c39dd5ee69208d2025-08-20T03:10:17ZengNature PortfolioNature Communications2041-17232025-04-0116111210.1038/s41467-025-58276-6Coding schemes in neural networks learning classification tasksAlexander van Meegen0Haim Sompolinsky1Center for Brain Science, Harvard UniversityCenter for Brain Science, Harvard UniversityAbstract Neural networks posses the crucial ability to generate meaningful representations of task-dependent features. Indeed, with appropriate scaling, supervised learning in neural networks can result in strong, task-dependent feature learning. However, the nature of the emergent representations is still unclear. To understand the effect of learning on representations, we investigate fully-connected, wide neural networks learning classification tasks using the Bayesian framework where learning shapes the posterior distribution of the network weights. Consistent with previous findings, our analysis of the feature learning regime (also known as ‘non-lazy’ regime) shows that the networks acquire strong, data-dependent features, denoted as coding schemes, where neuronal responses to each input are dominated by its class membership. Surprisingly, the nature of the coding schemes depends crucially on the neuronal nonlinearity. In linear networks, an analog coding scheme of the task emerges; in nonlinear networks, strong spontaneous symmetry breaking leads to either redundant or sparse coding schemes. Our findings highlight how network properties such as scaling of weights and neuronal nonlinearity can profoundly influence the emergent representations.https://doi.org/10.1038/s41467-025-58276-6
spellingShingle Alexander van Meegen
Haim Sompolinsky
Coding schemes in neural networks learning classification tasks
Nature Communications
title Coding schemes in neural networks learning classification tasks
title_full Coding schemes in neural networks learning classification tasks
title_fullStr Coding schemes in neural networks learning classification tasks
title_full_unstemmed Coding schemes in neural networks learning classification tasks
title_short Coding schemes in neural networks learning classification tasks
title_sort coding schemes in neural networks learning classification tasks
url https://doi.org/10.1038/s41467-025-58276-6
work_keys_str_mv AT alexandervanmeegen codingschemesinneuralnetworkslearningclassificationtasks
AT haimsompolinsky codingschemesinneuralnetworkslearningclassificationtasks