Lab News

Alix Norton receives a UW Mary Gates Undergraduate Research Scholar Award, 2009.

From the "UNIVERSITY OF WASHINGTON - Twelfth Annual Undergraduate Research Symposium"

The Role of Dopamine in Novelty and Taste Aversion Learning
Alix Norton, Senior, Psychology
Mentor: Sheri Mizumori, Psychology
Mentor: Min Jung Kim, Psychology

Dopamine (DA) plays a crucial role in the neurobiology of learning and memory by providing information about reward prediction error, incentive salience of environmentalcues, and the novelty value of a particular stimulus. The neural function of DA in the processing of rewards has been thoroughly explored in the last several years. More recent studies have begun to focus on the role of DA in response to aversive stimuli and conditioning.

In the current study, we explore a form of aversive conditioning known as conditioned taste aversion (CTA). CTA is a type of classical conditioning in which animals remember a taste stimulus and avoid consuming it once they have experienced the pairing of a novel taste (CS,conditioned stimulus) followed by the sensation of nausea
(US, unconditioned stimulus). In a typical laboratory experiment, a sweet taste such as saccharin is used as the CS, and LiCl (lithium chloride, a nausea-inducing agent)as the US. The dramatic changes in behavior after this
aversive taste conditioning period have been well presented in previous studies.

Our research focuses on both the dopaminergic neural activity as well as relevant behavioral reactions during the CTA process. Using a hyperdrive recording technique, neural activity of several single units can be simultaneously recorded while an animal performs a task. CTA learning targets neurons in the midbrain area, which is known to be a major source of dopamine in brain functioning. Our main interest in this study is how midbrain neurons process the same taste stimulus (e.g. saccharin) differentially according to the animal’s familiarity or novelty associated with the CS.

This study provides a new aspect of the dopaminergic role in reward processing, which can broaden our understanding in human domains of learning, such as drug addiction.

The Guthrie Prize is a high honor for any undergraduate student.  Entries may be either an empirical paper, a conceptual paper, a literature review, or a research proposal.  The prize was established to encourage excellent writing about psychology that was broad in scope and accessible to the non-specialist.

Best Empirical Paper, 2009:  Alix B. W. Norton

Encoding of Taste Novelty by Midbrain Neurons

Sponsored by Sheri Mizumori, Ph.D.

Adria Martig received the 2009 Committee on Animal Research & Ethics Imprinting Award from the APA to participate in the APA annual convention in Toronto in August.  She will be the guest of APA at several events honoring the awardees, including a mentoring session and an opportunity to present her research.   She is with the Mizumori lab.

Cortney Taylor received three quarters of funding from the Mary Gates Undergraduate Research scholarship fund in 2009. She is conducting research on how the brain controls its response to rewarding stimuli. Her advisor is Sheri J. Y. Mizumori.

Adria Martig, of the Mizumori Lab, received a UW Psychology Department's Distinguished Teaching Award 2008, for Graduate Students for outstanding service and excellence in teaching.