Honors Program


Date of this Version


Document Type



Weddle, M. 2022. Methamphetamine Dependence and Its Effect on the Ventral Striatum. Undergraduate Honors Thesis. University of Nebraska-Lincoln.


Copyright Makenna Weddle 2022.


In this study, I addressed the effects of chronic methamphetamine dependence on the motivational function of the brain to non-drug-related reward cues. Methamphetamine is one of the most used illicit substances worldwide (U.S. Department of Health and Human Services, 2019), and it affects the motivational function of an individual by altering the structures and functions of the dopaminergic system. Methamphetamine increases the neural activity of the ventral tegmental area and ventral striatum by blocking dopamine reuptake and stimulating dopamine release (Jang et al., 2017). Consequently, the effects of dopamine increase within the brain’s motivational system during methamphetamine use (Tanaka, O’Doherty, & Sakagami, 2019). Here, functional magnetic resonance imaging (fMRI) was used to assess the effects of chronic methamphetamine use on reward-related blood-oxygen-level dependent (BOLD) signal activation in the ventral striatum of the brain. Participants underwent an incentive processing task (Hubbard et al., 2020a,b) during fMRI. Our study consisted of 24 participants that presented with active methamphetamine dependence and 28 non-substance using controls. I tested whether participants with active methamphetamine dependence exhibited decreased ventral striatal (BOLD) activations during monetary reward cues relative to controls.