Brain-Like Processing Pathways Form in Models With Heterogeneous Experts

Fuente: arXiv
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Main Authors: Cook, Jack, Akarca, Danyal, Costa, Rui Ponte, Achterberg, Jascha
Format: Preprint
Published: 2025
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author Cook, Jack
Akarca, Danyal
Costa, Rui Ponte
Achterberg, Jascha
author_facet Cook, Jack
Akarca, Danyal
Costa, Rui Ponte
Achterberg, Jascha
contents The brain is made up of a vast set of heterogeneous regions that dynamically organize into pathways as a function of task demands. Examples of such pathways can be found in the interactions between cortical and subcortical networks during learning, or in sub-networks specializing for task characteristics such as difficulty or modality. Despite the large role these pathways play in cognition, the mechanisms through which brain regions organize into pathways remain unclear. In this work, we use an extension of the Heterogeneous Mixture-of-Experts architecture to show that heterogeneous regions do not form processing pathways by themselves, implying that the brain likely implements specific constraints which result in the reliable formation of pathways. We identify three biologically relevant inductive biases that encourage pathway formation: a routing cost imposed on the use of more complex regions, a scaling factor that reduces this cost when task performance is low, and randomized expert dropout. When comparing our resulting \textit{Mixture-of-Pathways} model with the brain, we observe that the artificial pathways in our model match how the brain uses cortical and subcortical systems to learn and solve tasks of varying difficulty. In summary, we introduce a novel framework for investigating how the brain forms task-specific pathways through inductive biases, and the effects these biases have on the behavior of Mixture-of-Experts models.
format Preprint
id arxiv_https___arxiv_org_abs_2506_02813
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Brain-Like Processing Pathways Form in Models With Heterogeneous Experts
Cook, Jack
Akarca, Danyal
Costa, Rui Ponte
Achterberg, Jascha
Neurons and Cognition
Neural and Evolutionary Computing
The brain is made up of a vast set of heterogeneous regions that dynamically organize into pathways as a function of task demands. Examples of such pathways can be found in the interactions between cortical and subcortical networks during learning, or in sub-networks specializing for task characteristics such as difficulty or modality. Despite the large role these pathways play in cognition, the mechanisms through which brain regions organize into pathways remain unclear. In this work, we use an extension of the Heterogeneous Mixture-of-Experts architecture to show that heterogeneous regions do not form processing pathways by themselves, implying that the brain likely implements specific constraints which result in the reliable formation of pathways. We identify three biologically relevant inductive biases that encourage pathway formation: a routing cost imposed on the use of more complex regions, a scaling factor that reduces this cost when task performance is low, and randomized expert dropout. When comparing our resulting \textit{Mixture-of-Pathways} model with the brain, we observe that the artificial pathways in our model match how the brain uses cortical and subcortical systems to learn and solve tasks of varying difficulty. In summary, we introduce a novel framework for investigating how the brain forms task-specific pathways through inductive biases, and the effects these biases have on the behavior of Mixture-of-Experts models.
title Brain-Like Processing Pathways Form in Models With Heterogeneous Experts
topic Neurons and Cognition
Neural and Evolutionary Computing
url https://arxiv.org/abs/2506.02813