UNIVERSITY GRADUATE SCHOOL BULLETIN

ANNOUNCEMENT

Florida International University

University Graduate School

Doctoral Dissertation Defense

Abstract

Etiological Understanding of Adolescent Substance Use in the Context of the Developing Brain

by

Benjelene D. Sutherland

Adolescence is marked by increased risk-taking given the differential developmental trajectory of striatal regions and the prefrontal cortex (PFC). Both the striatum and PFC are implicated in substance use (SU) among adults and adolescents. Notably, adolescent SU rates remain problematic making it a public health concern. As such, identifying promising prevention and intervention targets is a priority to reduce use onset and/or escalation.

In the current series of studies, I utilized task-based functional magnetic resonance imaging (fMRI), behavioral, and self-report measures to characterize mechanistic paths impacting youth SU. In study 1, I examined the interrelations of working memory (WM) and reward-related brain activity, anhedonia, impulsivity, and adolescent e-cigarette use. Outcomes highlighted anhedonia and impulsivity as significant mediators in an indirect association between altered dorsomedial (dm)PFC activity and e-cigarette use. Additionally, I observed a direct association between striatal hyperactivity and e-cigarette use above and beyond anhedonia and impulsivity. In study 2, I investigated WM-related brain activations and deactivations in relation to adolescent e-cigarette, marijuana, and alcohol use via WM-related task performance and alexithymia. Findings revealed that only alexithymia mediated the link between altered lateral (l)PFC (and superior temporal gyrus [STG]) activity and e-cigarette use. Such findings were not observed in the marijuana and alcohol models. Lastly, in study 3, we similarly considered WM-related brain activations and deactivations and if they were predictive of attention problems, and, in turn, intentions to use nicotine, marijuana, or alcohol among a much larger sample of pre-adolescents. Outcomes highlighted attention problems as a significant mediator in the association between altered lPFC activity and nicotine and marijuana use intentions. Such findings were not observed for the alcohol model.

Together, these studies’ highlight striatal and PFC activity as important neurobiological targets for adolescent nicotine and cannabis use via psychological factors related to emotional processes as well as internalizing and externalizing behaviors. These outcomes provide insight into why intervention techniques such as WM training, mindfulness meditation, or reward savoring may reduce adolescent SU. I speculate that such strategies may be viable ways to modulate PFC and striatal activity leading to improvements in attentional control, emotional awareness, anhedonia, and impulsivity.

Date: June 4th, 2026 Department: Psychology

Time: 12:00 p.m. Eastern Major Professor: Dr. Matthew T. Sutherland

Place: AHC4 Room 302

Zoom: https://fiu.zoom.us/j/81518384255