Research

Neural Systems, Inhibitory Control, and Methamphetamine Dependence

We are conducting research on brain structure and function in individuals with Methamphetamine Use Disorder. Chronic use of methamphetamine impairs cognitive brain function, and we are investigating how cognitive deficits in methamphetamine are related to the structure of people who misuse. We are also using functional MRI to assess how brain activity differs between these people and healthy, control participants. We are investigating how potential treatments may help improve the cognition and brain function of individuals with Methamphetamine Use Disorder. This includes the use of an exercise training regimen and medications. 

Dopamine Receptor Upregulation in Stimulant Use Disorder

Stimulant Use Disorder is characterized a deficit in D2-type dopamine receptors in the striatum. In healthy people, these receptors are liked to self-control and adaptive decision-making, and substantial evidence suggests that improving signaling through them can improve those cognitive functions. We have shown that exercise training as an adjunct to behavioral therapy upregulated D2-type dopamine receptors in people with Methamphetamine Use Disorder to the levels in healthy controls. This project uses multi-modal brain imaging to evaluate whether receptor upregulation in this population is associated with improved brain function.  In addition, potential pharmacological upregulation of D2-type receptors with varenicline is being evaluated using brain imaging (PET and fMRI scanning) and behavioral assay.  

Sex Differences in the Neural Correlates of Cigarette Smoking

The use of combustible tobacco products, primarily cigarettes, is responsible for more than half a million preventable deaths per year in the US. Most people who smoke want to quit, and available treatments help some of them. Although there are medications to facilitate smoking cessation, quit rates are low and there are sex differences in the untoward effects of smoking and in the response to smoking-cessation medications. This project uses multi-modal brain imaging (structural and functional fMRI, magnetic resonance spectroscopy) and behavioral assay to identify sex differences in the neural correlates of craving, withdrawal and responses to smoking. The goal is to develop personalized treatments that consider the role of sex in facilitating smoking cessation.

Cannabidiol as Adjunctive Treatment for Opioid Use Disorder

With over 100,000 overdose deaths in the US during 2021, the need for novel treatments cannot be overstated. There are FDA-approved medications for Opioid Use Disorder, the most efficacious being the opioid replacement therapies, buprenorphine. And methadone. Yet within months of initiating treatment, about half of the patients relapse. One problem that is cited is craving for opioids, and this craving is thought to drive relapse. Following reports that cannabidiol, a non-psychoactive cannabis derivative, reduces opioid craving, this project is evaluating the safety and initial efficacy of cannabidiol as adjunctive therapy for patients receiving opioid replacement therapy with buprenorphine.

Glutamate receptors and Stimulant Use Disorder

While the mGlu5 glutamate receptor is linked to a number of important brain disorders and to the propensity of animals to self-administer methamphetamine, this receptor has not been evaluated in people with Methamphetamine Use Disorder. This project examines regional brain mGlu5 levels in individuals with Methamphetamine Use Disorder and examines relationships with impairments in decision making, cognitive function, and psychiatric symptoms.