Journal
CEREBRAL CORTEX
Volume 29, Issue 1, Pages 397-409Publisher
OXFORD UNIV PRESS INC
DOI: 10.1093/cercor/bhy264
Keywords
connectome; dopamine depletion; functional connectivity; neural dynamics; signal variability
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Funding
- Canada First Research Excellence Fund
- Natural Sciences and Engineering Research Council of Canada (NSERC Discovery Grant RGPIN) [017-04 265]
- Fonds de recherche du Quebec - Sante (Chercheur Boursier)
- Healthy Brains for Healthy Lives (HBHL) initiative at McGill University
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Dopaminergic projections are hypothesized to stabilize neural signaling and neural representations, but how they shape regional information processing and large-scale network interactions remains unclear. Here we investigated effects of lowered dopamine levels on within-region temporal signal variability (measured by sample entropy) and between-region functional connectivity (measured by pairwise temporal correlations) in the healthy brain at rest. The acute phenylalanine and tyrosine depletion (APTD) method was used to decrease dopamine synthesis in 51 healthy participants who underwent resting-state functional MRI (fMRI) scanning. Functional connectivity and regional signal variability were estimated for each participant. Multivariate partial least squares (PLS) analysis was used to statistically assess changes in signal variability following APTD as compared with the balanced control treatment. The analysis captured a pattern of increased regional signal variability following dopamine depletion. Changes in hemodynamic signal variability were concomitant with changes in functional connectivity, such that nodes with greatest increase in signal variability following dopamine depletion also experienced greatest decrease in functional connectivity. Our results suggest that dopamine may act to stabilize neural signaling, particularly in networks related to motor function and orienting attention towards behaviorally-relevant stimuli. Moreover, dopamine-dependent signal variability is critically associated with functional embedding of individual areas in large-scale networks.
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