This application outlines a carefully orchestrated program of didactic and practical research training for a doctoral student in human behavioral neuroscience, and provides plans for professional and career development training. The proposed research project will investigate whether drugs of abuse produce positive memory biases, biasing an individual to preferentially remember positive, relative to negative and neutral, information. Positive memory biases may contribute to the likelihood of continued drug use. Two studies are described which will explore the effect of d-amphetamine (AMP), a prototypic stimulant drug of abuse known to produce feelings of euphoria, on memory for emotional information. The first study will examine the effect of acute AMP on memory encoding (i.e., perception and consolidation) of positive, negative, and neutral stimuli by administering the drug during encoding, and testing memory retrieval two days later, without the drug. The second study will examine the effect of acute AMP on memory retrieval (i.e., recall) of positive, negative, and neutral stimuli by allowing participants to encode material first, without drug, and then testing their memory retrieval for the material two days later, under the influence of AMP. In both studies, the emotional information will consist of stimuli with positive, neutral, and negative affective content. It is hypothesized that AMP will induce a memory bias for positive stimuli when administered at encoding or retrieval. A drug-induced bias for encoding positive events or stimuli may suggest that drug users tend to over-remember positive, and under- remember negative, drug-related events. A drug-induced bias during retrieval may increase the likelihood of using a drug by enhancing access to existing, positive memories. Thus, a drug-induced bias in either encoding or retrieval of memories could explain how a drug enhances the salience of positive events. In addition to the proposed research project, this application describes a detailed academic and professional training plan to prepare the candidate for further research in this area, and for a career in human drug abuse research. He will attend regular seminar series on drug abuse and memory, and enroll in elective courses in cognition and memory and in experimental design and statistical techniques. He will have the opportunity to train students in conducting research, give occasional lectures, and attend scientific meetings. He will be expected to prepare publish his findings, and to present at scientific meetings.
Overall, the project will provide an outstanding training opportunity for a junior scientist interested in clinical psychopharmacology related to drug abuse. The proposed research investigates a novel mechanism by which drugs can increase the likelihood of future drug use, by creating a bias in memory for positive, over negative or neutral events and stimuli in the environment. Drugs may create a bias for positive memories, and this, in turn, could make the drug more attractive and ultimately lead to compulsive use. The project has public health significance because it may lead to ways to treat or stop the drug dependence process.
| Ballard, Michael E; Weafer, Jessica; Gallo, David A et al. (2015) Effects of acute methamphetamine on emotional memory formation in humans: encoding vs consolidation. PLoS One 10:e0117062 |
| Ballard, Michael Edward; Gallo, David A; de Wit, Harriet (2014) Amphetamine increases errors during episodic memory retrieval. J Clin Psychopharmacol 34:85-92 |
| Ballard, Michael E; Gallo, David A; de Wit, Harriet (2013) Pre-encoding administration of amphetamine or THC preferentially modulates emotional memory in humans. Psychopharmacology (Berl) 226:515-29 |
