Final Dissertation Defense Announcement

STUDENT NAME: Joseph Happer, M.S.

COMMITTEE CHAIRPERSON:

Ksenija Marinkovic, Ph.D., Associate Professor, Department of Psychology, SDSU

COMMITTEE MEMBERS:

Joanna Jacobus, Ph.D., Associate Adjunct Professor, Department of Psychiatry, UCSD Carrie McDonald, Ph.D., Professor in Residence, Department of Psychiatry, UCSD Marc Schuckit, Ph.D., Distinguished Professor, Department of Psychiatry, UCSD Martin Sereno, Ph.D., Professor Emeritus, Department of Psychology, SDSU

TITLE OF DISSERTATION: Examining the Spatio-Temporal Dynamics of Inhibitory Control in the Context of Attentional Processing, Genetic Variability, Risk for Alcohol Misuse, and Alcohol Challenge

DATE OF DEFENSE: Monday, June 12, 2023 TIME OF DEFENSE: 12:00PM

LOCATION OF DEFENSE: See Program

ABSTRACT

Rationale: Inhibitory control is an executive function essential for flexible and adaptive behavior. This 3-paper dissertation examined its spatio- (“where”) temporal (“when”) neural dynamics with inhibitory Go/NoGo paradigms. A multimodal anatomically- constrained magnetoencephalography (aMEG) method combined the temporal precision and distributed source modeling of MEG with structural MRI and provided insight into the anatomical distribution of the engaged areas and their functional interdependence.

Study 1 examined the relative contributions of attentional and inhibition-related processes using a modified Go/NoGo task in a cohort of healthy participants (N=26). Attentional capture was subserved by early activity within right-lateralized temporoparietal areas followed by activation of a “braking” network comprised of ventrolateral prefrontal areas responding specifically to inhibitory demands. Medial prefrontal areas supported integrative processing of inhibitory and attentional stimulus properties.

Study 2 explored how genetically-determined cortical dopamine availability in individuals genotyped for the COMT Val¹⁵⁸Met polymorphism (Met/Met: N=21; Val/Val: N=21) modulated neural activity of response preparation, inhibition, and execution. Met homozygotes (high dopamine) exhibited an increase in beta power during early motor preparation suggestive of a transient “pause,” which could underlie the tendency of Met homozygotes to be more cautious and inhibited. In contrast, Val homozygotes (low dopamine) commonly endorse higher impulsivity. They exhibited greater beta decrease during early motor preparation, indicative of high response readiness.

Study 3 evaluated the effects of alcohol intoxication on the neurocircuitry of inhibitory control in social drinkers with (FHP) or without (FHN) a family history of alcoholism (N=19 per group), a heritable, multifaceted risk factor for the development of alcohol use disorder (AUD). In FHP, lower inhibition-induced oscillatory power was associated with extraversion. Converging evidence across behavioral and neural indices supports low responsivity of FHP to alcohol intoxication, which may mediate the development of AUD.

The multimodal aMEG method can provide high-resolution insight into the neural underpinnings of inhibitory control with implications for healthy behavior and genetically- determined interindividual differences in impulsivity. Because of their sensitivity to synaptic signaling, these indices can reveal neural signature of the acute and persistent impact of alcohol on self-regulatory functions, and may serve as endophenotypes of disinhibitory disorders, including the vulnerability to AUD.

Final Dissertation Defense Announcement

STUDENTNAME:

JackBrady

COMMITTEECHAIRPERSON:

Aaron J. Blashill, Professor,Psychology, San Diego State University

COMMITTEEMEMBERS: 

Kristen Wells, Professor, Psychology, San Diego StateUniversity

Scott Roesch, Professor, Psychology, San Diego StateUniversity

David J. Moore, Professor in Residence, Psychiatry,University of California San Diego

Jessica Montoya, Assistant Professor, Psychiatry,University of California San Diego

TITLEOF DISSERTATION: 

TheEffect of Patient Navigation for PrEP-related Health Care on Mental Healthamong Latinx Sexual Minority Men: Mediation through Social Support

DATEOF DEFENSE: 06/15/2023

TIMEOF DEFENSE: 8:45AM – 10:15AM

LOCATIONOF DEFENSE: See Program 

ABSTRACT

Rationale: Sexual minority men (SMM; e.g., men whoidentify as gay/bisexual and/or report same-gender attraction/sexual behavior)are disproportionately affected by internalizing disorders and symptoms (e.g.,anxiety and depressive disorders/symptoms) in comparison to their heterosexualmale peers. Hispanic/Latinx SMM may be especially burdened by internalizingdisorders/symptoms due to decreased access to culturally competent health care,stigma surrounding mental disorders, and stress from within the SMM community. Patientnavigation (PN) is a partnership-based, individualized intervention thatfocuses on decreasing barriers to health care. Patient navigation forpre-exposure prophylaxis (PrEP)—a medication taken to prevent HIV infection—couldreduce internalizing symptoms of anxiety and depression among Hispanic/LatinxSMM by providing social support.

Design: This study used secondary data analysisto examine the impact of PN on internalizing symptom outcomes through six-monthfollow-up (6MFU) among a sample of Hispanic/Latinx SMM between the ages of 18and 29 (N = 57). Data analyzed were from a randomized controlled trialinvestigating the efficacy of a PN intervention (versus usual care) to assistHispanic/Latinx SMM at high risk for HIV infection with accessing PrEP. Hispanic/LatinxSMM peer patient navigators were utilized to provide culturally competent careand decrease social stigma. Usual care consisted of written information aboutPrEP, sexual health and HIV prevention services, and how to access care. It washypothesized that the PN condition would be associated with decreasedinternalizing symptoms and that the effect would be mediated by two socialsupport constructs at three-month follow-up: emotional support and informationalsupport. Data were analyzed using two analytic approaches: 1) cross-laggedpanel models and 2) latent difference scores.

Results: The PN condition was not associatedwith a significant decrease in internalizing symptoms at 6MFU and the effectwas not mediated through social support.

Conclusions: Results may be related to the flooreffect of internalizing symptoms at baseline, analyses that assumed changes insocial support were occurring within the first three months of the study, andvariability in the frequency of using PN services. Future studies would benefitfrom gathering data at additional time points and selecting participants withhigher internalizing symptoms and/or lower social support.