James C. Eliassen

Biography

My research examines learning and the effects of drug abuse and addiction on brain function. I investigate this by studying how the brains of individuals who use addictive drugs differ from the brains of healthy individuals. Using associative learning tasks (games like "Rock, Paper, Scissors") in combination with a brain imaging technique called functional MRI, I study how the brain responds to learning and how drug use alters the typical pattern of brain activity seen in healthy individuals. In addition to fMRI, I also employ structural MRI, diffusion-weighted/diffusion tensor imaging, MR spectroscopy and event-related potential EEG (ERPs).

Research Interest

The goal of my research is to understand the neural origins of addiction in order to improve addiction treatment. Specifically, my work encompasses two objectives: 1. To identify the brain regions that participate in reinforcement learning and understand how these regions are affected by addiction, 2. To develop magnetic resonance imaging (MRI) biomarkers of structural, functional and biochemical changes and electrophysiological changes in the brain during addiction to be used to assess treatment success. Drugs of abuse directly and powerfully activate the midbrain dopamine system, which typically participates in reinforcement learning regarding ordinary rewards such as food. Drugs of abuse activate this same system in response to intoxication, but unlike ordinary rewards, the effects of drugs on the dopamine system does not diminish with repeated use. Through the action of drugs on the dopamine system, addicted individuals learn to engage in compulsive drug seeking behaviors because these behaviors predict the reward of intoxication. The difference between typical and addicted reward behavior is that a hungry animal will eat until it is satiated and then satisfy other needs, while a drug addict’s desire for intoxication may prevail over the desire to maintain a rewarding lifestyle, including good health, satisfactory job performance, and strong social relationships. In most people the negative consequences of a deteriorating lifestyle outweigh the reward of intoxication and drug abuse does not lead to addiction. In other words, the punishments outweigh the rewards at some point for most people. Reinforcement learning models do not distinguish between reward and punishment as effective reinforcers of behavior, but addiction appears to distinguish reward and punishment because the reward of intoxication outweighs the punishments of continued drug abuse. We are investigating associative learning disorder models of addiction with an eye toward trying to understand why the unpleasant consequences of serious drug dependency does not lead to stoppage of drug use.