Deconstructing Delay Discounting in Human Cocaine Addiction Using Computational Modeling and Neuroimaging

Area of Science:

• Neuroscience
• Computational Psychiatry
• Behavioral Economics

Background:

• Delay discounting, the preference for immediate rewards, is linked to impulsivity and psychiatric disorders.
• Neuropsychological underpinnings of abnormal delay discounting remain unclear.
• This study investigates choice and rate processes in delay discounting using computational models and neuroimaging.

Purpose of the Study:

• To deconstruct delay discounting into choice and rate processes.
• To compare the reliability of different computational models for estimating discounting parameters.
• To examine the association between white matter connectivity and delay discounting in cocaine use disorder (CUD).

Main Methods:

• 107 patients with CUD and 81 healthy controls completed the Monetary Choice Questionnaire.
• Discounting rates were calculated using Kirby, logistic regression, and Bayesian models, with Bayesian models including a choice sharpness parameter.
• Diffusion tensor imaging was used to analyze white matter tracts connecting executive control and valuation networks.

Main Results:

• Patients with CUD exhibited higher discounting rates and lower choice sharpness, indicating increased choice indifference.
• The full hierarchical Bayesian model demonstrated superior reliability in parameter recovery compared to other methods.
• White matter streamlines connecting the executive control network and nucleus accumbens predicted discounting rates in healthy individuals, but not in patients with CUD.

Conclusions:

• A novel computational model accurately captures delay discounting and choice sharpness, offering better explanation for impulsive choices in CUD.
• This research identifies a unique neuropsychological profile of impulsive decision-making.
• Findings may extend to understanding impulsivity in other clinical populations.