Metabolite transport through glial networks stabilizes the dynamics of learning

TL;DR

This paper presents a model where glial cells regulate neural stability during learning by distributing metabolic resources, preventing runaway synaptic growth and maintaining neural network stability.

Contribution

It introduces a novel model combining neural and glial networks, highlighting the role of metabolite transport in stabilizing learning dynamics.

Findings

Glial metabolite transport prevents runaway synaptic growth.

Diffusive transport stabilizes neural network during learning.

Glial processes are crucial for neural stability during plasticity.

Abstract

Learning and memory are acquired through long-lasting changes in synapses. In the simplest models, such synaptic potentiation typically leads to runaway excitation, but in reality there must exist processes that robustly preserve overall stability of the neural system dynamics. How is this accomplished? Various approaches to this basic question have been considered. Here we propose a particularly compelling and natural mechanism for preserving stability of learning neural systems. This mechanism is based on the global processes by which metabolic resources are distributed to the neurons by glial cells. Specifically, we introduce and study a model comprised of two interacting networks: a model neural network interconnected by synapses which undergo spike-timing dependent plasticity (STDP); and a model glial network interconnected by gap junctions which diffusively transport metabolic resources among the glia and, ultimately, to neural synapses where they are consumed. Our main result is that the biophysical constraints imposed by diffusive transport of metabolic resources through the glial network can prevent runaway growth of synaptic strength, both during ongoing activity and during learning. Our findings suggest a previously unappreciated role for glial transport of metabolites in the feedback control stabilization of neural network dynamics during learning.