Compartmental-reaction diffusion framework for microscale dynamics of extracellular serotonin in brain tissue

Fuente: arXiv
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Autores principales: Pelz, Merlin, Janusonis, Skirmantas, Handy, Gregory
Formato: Preprint
Publicado: 2025
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author Pelz, Merlin
Janusonis, Skirmantas
Handy, Gregory
author_facet Pelz, Merlin
Janusonis, Skirmantas
Handy, Gregory
contents Serotonin (5-hydroxytryptamine) is a major neurotransmitter whose release from densely distributed serotonergic varicosities shapes plasticity and network integration throughout the brain, yet its extracellular dynamics remain poorly understood due to the sub-micrometer and millisecond scales involved. We develop a mathematical framework that captures the coupled reaction-diffusion processes governing serotonin signaling in realistic tissue microenvironments. Formulating a two-dimensional compartmental-reaction diffusion system, we use strong localized perturbation theory to derive an asymptotically equivalent set of nonlinear integro-ODEs that preserve diffusive coupling while enabling efficient computation. We analyze period-averaged steady states, establish bounds using Jensen's inequality, obtain closed-form spike maxima and minima, and implement a fast marching-scheme solver based on sum-of-exponentials kernels. These mathematical results provide quantitative insight into how firing frequency, varicosity geometry, and uptake kinetics shape extracellular serotonin. The model reveals that varicosities form diffusively coupled microdomains capable of generating spatial "serotonin reservoirs," clarifies aspects of local versus volume transmission, and yields predictions relevant to interpreting high-resolution serotonin imaging and the actions of selective serotonin-reuptake inhibitors.
format Preprint
id arxiv_https___arxiv_org_abs_2512_10983
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Compartmental-reaction diffusion framework for microscale dynamics of extracellular serotonin in brain tissue
Pelz, Merlin
Janusonis, Skirmantas
Handy, Gregory
Tissues and Organs
Cell Behavior
Neurons and Cognition
92C20
Serotonin (5-hydroxytryptamine) is a major neurotransmitter whose release from densely distributed serotonergic varicosities shapes plasticity and network integration throughout the brain, yet its extracellular dynamics remain poorly understood due to the sub-micrometer and millisecond scales involved. We develop a mathematical framework that captures the coupled reaction-diffusion processes governing serotonin signaling in realistic tissue microenvironments. Formulating a two-dimensional compartmental-reaction diffusion system, we use strong localized perturbation theory to derive an asymptotically equivalent set of nonlinear integro-ODEs that preserve diffusive coupling while enabling efficient computation. We analyze period-averaged steady states, establish bounds using Jensen's inequality, obtain closed-form spike maxima and minima, and implement a fast marching-scheme solver based on sum-of-exponentials kernels. These mathematical results provide quantitative insight into how firing frequency, varicosity geometry, and uptake kinetics shape extracellular serotonin. The model reveals that varicosities form diffusively coupled microdomains capable of generating spatial "serotonin reservoirs," clarifies aspects of local versus volume transmission, and yields predictions relevant to interpreting high-resolution serotonin imaging and the actions of selective serotonin-reuptake inhibitors.
title Compartmental-reaction diffusion framework for microscale dynamics of extracellular serotonin in brain tissue
topic Tissues and Organs
Cell Behavior
Neurons and Cognition
92C20
url https://arxiv.org/abs/2512.10983