Universität zu Köln

Wiencke, Kathleen, Horstmann, Annette ORCID: 0000-0001-6184-8484, Mathar, David, Villringer, Arno and Neumann, Jane (2020). Dopamine release, diffusion and uptake: A computational model for synaptic and volume transmission. PLoS Comput. Biol., 16 (11). SAN FRANCISCO: PUBLIC LIBRARY SCIENCE. ISSN 1553-7358

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Abstract

Computational modeling of dopamine transmission is challenged by complex underlying mechanisms. Here we present a new computational model that (I) simultaneously regards release, diffusion and uptake of dopamine, (II) considers multiple terminal release events and (III) comprises both synaptic and volume transmission by incorporating the geometry of the synaptic cleft. We were able to validate our model in that it simulates concentration values comparable to physiological values observed in empirical studies. Further, although synaptic dopamine diffuses into extra-synaptic space, our model reflects a very localized signal occurring on the synaptic level, i.e. synaptic dopamine release is negligibly recognized by neighboring synapses. Moreover, increasing evidence suggests that cognitive performance can be predicted by signal variability of neuroimaging data (e.g. BOLD). Signal variability in target areas of dopaminergic neurons (striatum, cortex) may arise from dopamine concentration variability. On that account we compared spatio-temporal variability in a simulation mimicking normal dopamine transmission in striatum to scenarios of enhanced dopamine release and dopamine uptake inhibition. We found different variability characteristics between the three settings, which may in part account for differences in empirical observations. From a clinical perspective, differences in striatal dopaminergic signaling contribute to differential learning and reward processing, with relevant implications for addictive- and compulsive-like behavior. Specifically, dopaminergic tone is assumed to impact on phasic dopamine and hence on the integration of reward-related signals. However, in humans DA tone is classically assessed using PET, which is an indirect measure of endogenous DA availability and suffers from temporal and spatial resolution issues. We discuss how this can lead to discrepancies with observations from other methods such as microdialysis and show how computational modeling can help to refine our understanding of DA transmission. Author summary The dopaminergic system of the brain is very complex and affects various cognitive domains like memory, learning and motor control. Alterations have been observed e.g. in Parkinson's or Huntington's Disease, ADHD, addiction and compulsive disorders, such as pathological gambling and also in obesity. We present a new computational model that allows to simulate the process of dopamine transmission from dopaminergic neurons originated in source brain regions like the VTA to target areas such as the striatum on a synaptic and on a larger, volume-spanning level. The model can further be used for simulations of dopamine related diseases or pharmacological interventions. In general, computational modeling helps to extend our understanding, gained from empirical research, to situations were in vivo measurements are not feasible.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wiencke, Kathleen UNSPECIFIED UNSPECIFIED UNSPECIFIED Horstmann, Annette UNSPECIFIED orcid.org/0000-0001-6184-8484 UNSPECIFIED Mathar, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Villringer, Arno UNSPECIFIED UNSPECIFIED UNSPECIFIED Neumann, Jane UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-312837
DOI:	10.1371/journal.pcbi.1008410
Journal or Publication Title:	PLoS Comput. Biol.
Volume:	16
Number:	11
Date:	2020
Publisher:	PUBLIC LIBRARY SCIENCE
Place of Publication:	SAN FRANCISCO
ISSN:	1553-7358
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BASE-LINE OCCUPANCY; NUCLEUS-ACCUMBENS; IN-VIVO; EXTRACELLULAR DOPAMINE; SIGNAL VARIABILITY; RAT STRIATUM; NEUROTRANSMISSION; MODULATION; NEURONS; AUTORECEPTORS Multiple languages Biochemical Research Methods; Mathematical & Computational Biology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/31283