The Inverted-U: A Literature Review on the Effect of Dopamine in Different Animal Models

Abstract

The functions and processes behind memory have been the subject of study in multiple scientific papers throughout the years. This has allowed for neuroscientists to distinguish between three types of memory: sensory memory, long-term memory, and short-term memory. My junior paper was a literature review that focused on the effect of different neurotransmitters (glutamate, dopamine, acetylcholine, serotonin, and histamine) on short-term memory. This revealed that an increase in concentration of most neurotransmitters results in improved performance in short-term or working memory tasks, except for dopamine. Dopamine has a unique and interesting inverted-U relationship where too little or too large an amount of dopamine can actually have detrimental effects on short-term memory. This paper describes how this inverted-U relationship is conserved across different animal models, specifically mice, rat, and primate models. It also describes how dopamine is regulated in each of these models and how changes in dopamine also changes aspects of cognitive behavior.