Astrocytic resource diffusion stabilizes persistent activity in neural fields
Noah Palmer, Heather L. Cihak, Daniele Avitabile, Zachary P. Kilpatrick
TLDR
This paper introduces an astrocyte-neural field model where astrocytic resource diffusion stabilizes persistent neural activity, crucial for working memory.
Key contributions
- Proposes a coupled astrocyte-neural field model for persistent activity in working memory.
- Identifies a two-stage stabilization mechanism involving astrocytic resource diffusion and synaptic replenishment.
- Shows astrocytic support suppresses drift instabilities, expanding the parameter regime for stable neural bumps.
Why it matters
This work bridges a critical gap in neural circuit models by incorporating astrocytic support, which is vital for sustained synaptic transmission. It provides a novel mechanism for understanding how persistent neural activity, fundamental to working memory, is stabilized. This could lead to better models of brain function and dysfunction.
Original Abstract
Persistent neural activity underlying working memory requires sustained synaptic transmission, yet the metabolic and neurotransmitter support provided by astrocyte networks is largely absent from spatially extended neural circuit models. We introduce a coupled astrocyte-neural field model in which synaptic efficacy is regulated by depletion and recovery of a conserved resource pool recycled and spatially redistributed through diffusively coupled astrocytes. We obtain explicit stationary bump profiles and self-consistency conditions for bump width and amplitude on a canonical ring architecture. Linearizing about these solutions while carefully accounting for perturbations at bump boundaries, we analyze the resulting spectral problem governing stability. Our analysis, supported by numerical simulations and low-dimensional Fourier truncations, reveals a two-stage stabilization mechanism: astrocytic diffusion smooths resource asymmetries created by small bump displacements, and synaptic replenishment transfers this smoothing back to the synaptic pool. Together, sufficiently strong diffusion and replenishment suppress drift instabilities and enlarge the parameter regime in which stationary bumps persist.
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