I graduated from the University of Houston in 2012 with my B.S. in Psychology. During my undergraduate career I volunteered to work with both the Clinical Neuroscience Research Team led by Dr. Merrill Hiscock and the Behavioral Neuroscience Research Team directed by Dr. J. Leigh Leasure. In spring of 2013 I began working as a research technician in Dr. M. Waleed Gaber’s Pediatric Oncology/Radiation Research Lab through the Baylor College of Medicine at Texas Children’s Hospital in Houston, Texas. In the fall of 2015 I joined the Psychopharmacology Laboratory led by Dr. Tony Riley at American University in Washington, D.C. as a Psychology Master’s Student in the Biological/Experimental thesis track. After successfully defending my Master’s thesis during the summer of 2017, I joined the doctoral program (PhD) in Behavior, Cognition and Neuroscience (BCaN) starting in the fall of 2018 and am happy to be able to continue my research with Dr. Riley.
My goals in behavioral neuroscience at the moment involve understanding the way drugs affect behavior; including drug taking, use, and abuse, as well as researching factors that may influence addiction vulnerability. Some factors that may impact abuse liability include: age, sex, drug history, species, strain, concurrent and simultaneous drug use, among others. At the moment, my work has been focused on characterizing the synthetic cathinones, specifically methylenedioxypyrovalerone (MDPV) and alpha-pyrrolidinopentiophenone (α-PVP) as well as their individual enantiomers. These psychostimulants are cocaine-like in their mechanism of action in that they are both potent monoamine reuptake blockers that do not stimulate release.
Drug use and abuse are thought to be a function of an affective balance, such that rewarding effects of the drug support intake while its aversive effects limit it. The studies I have performed recently have primarily focused on behavioral assays that index these affective properties and employed designs such as conditioned taste avoidance (CTA) and conditioned place preference (CPP). CTA exploits an animal’s tendency to avoid consumption of ordinarily preferred drug-paired solutions (i.e., water sweetened with saccharin), presumably due to an association between the taste (the conditioned stimulus, CS) and the drug’s aversive effects (the unconditioned stimulus, US). CPP is used as a measure for reward as the animal associates a distinct chamber with a drug’s rewarding effects and spends more time on the drug-paired side. These experimental designs were used both separately and in tandem (a combined CTA/CPP design) to assess the balance of reward and aversion associated with MDPV and α-PVP, which are factors that ultimately impact the likelihood of self-administration – the gold standard in determining abuse potential in human users. In addition to these assays I have assessed the effects that MDPV and α-PVP may have on hyperactivity and thermoregulation (effects that contribute to toxic reactions in humans, e.g., potentially fatal increases in body temperature and extreme tremor disorder).
My most recently completed study, which reached completion over this past summer, involved researching the stereo-selective effects of α-PVP. The goal of that project was to determine the relative contribution of each enantiomer of α-PVP in terms of their rewarding and aversive effects as well as their ability to induce hyperactivity and hyperthermia. This series of assessments took place at a single dose of 3.0 mg/kg. This dose was based on previous work in our laboratory in which racemic α-PVP (a 50:50 preparation of both R and S enantiomers) at 3.0 mg/kg induced a significant, but intermediate, suppression of saccharin consumption (see Nelson et al., 2017), allowing for assessments of the relative strength of conditioning by racemic α-PVP and its isomers. This paper is currently being reviewed for publication.
As part of my doctoral dissertation, and in order to further characterize α-PVP’s subjective effects, I am presently working on a drug discrimination paradigm involving racemic α-PVP as the training compound. Drug discrimination learning is a behavioral assay of the discriminative or subjective effects of specific drugs and assesses the degree of overlap of interoceptive stimulus effects with relevant comparison drugs. Such effects are often associated with the drug's abuse potential, and this procedure is widely used in pre-clinical assessments of drug use and abuse. As far as I am aware, no previous studies have employed α-PVP as the training compound, only as a probe compound. The reason why this order of exposure is significant is that experience with a specific drug can affect the subjective effects of any subsequent drug exposures, including future exposures to the training drug itself. Once we have more data collected, this project too will be presented at future conferences and prepared for publication. Future studies will focus more heavily on drug history, simultaneous, and concurrent drug use as well as sex and age differences.