Author ORCID Identifier

https://orcid.org/0000-0001-8235-237

Date Available

5-9-2024

Year of Publication

2024

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Arts and Sciences

Department/School/Program

Psychology

First Advisor

Dr. Michael J Wesley

Second Advisor

Dr. Mark T. Fillmore

Abstract

Value-based decision-making involves the coordinated effort of multiple brain regions to guide future choices based on past experiences. These processes are disrupted in cannabis use disorder, where individuals continue to use cannabis despite negative consequences. Reinforcement learning (RL) paradigms can be used to capture changes in the value of available options and may inform how the brain is impacted by frequent cannabis use. This study combined fMRI with behavioral modeling of probabilistic choice task data to compare value-based choices between young adults reporting daily/near daily cannabis use (CAN) and controls (CTRL). Participants selected one of two options reinforced ($0.25) at independent reward probabilities and switched unpredictably. Behavioral data were analyzed using t-tests, linear regressions, AIC model comparisons, and Wilcoxon Mann-Whitney U tests. Best-model derived value estimates were used in first-level GLMs to modulate brain activity at choice deliberation. CAN made fewer higher probability “rich” choices compared to CTRL. A learning model including learning rate, inverse temperature, and perseveration parameters was the best model for both groups. CAN had lower inverse temperature parameter estimates, indicative of a lower likelihood of using current option value to inform future choice. fMRI analyses demonstrated greater value-modulated activity in the left OFC and right hippocampal gyrus for CAN compared to CTRL. These results highlight more disadvantageous choices and hyperactivity in regions implicated in reward learning in people reporting daily/near daily cannabis use, revealing a potential mechanism for maladaptive decision-making in cannabis use disorder.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2024.108

Funding Information

This research was supported by the following intra- and extramural funding mechanisms:

  • The UNITE Predoctoral Fellowship (2023-Current)
  • National Institute on Drug Abuse T32 Research Training in Drug Abuse Behavior (NIDA T32 DA035200)
  • A Translational Determination of the Neurobehavioral Mechanisms of Maladaptive Dynamic Choice in Cocaine Use Disorder (NIDA R01 DA045023)
  • A Translational Determination of the Neurobehavioral Mechanisms of Maladaptive Dynamic Choice in Opioid Use Disorder (NIDA R01 DA047368)
  • Neural Mechanisms of Cannabinoid-Impaired Decision-Making in Emerging Adults (NIDA K01 DA047368)

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