Research Symposium

Investigator:  Tristan Darland, Ph.D., Associate Professor

Location:  Department of Biology, Starcher Hall, University of North Dakota

Project Title:  Genetic and epigenetic modulation of classic conditioning in Zebrafish

Description:  This research aims to understand how environment shapes an organism's ability to learn.  One of the most basic types of learning referred to as associative conditioning in which an organism learns to associate a primary stimulus, like food, with a secondary stimulus such as an auditory or visual cue.  Once an organism associates the two stimuli, it will respond to the secondary stimulus whether or not the primary stimulus is present.  This basic type of learning and memory is present in every vertebrate tested and even in some invertebrates.  The brain monoaminergic pathways have proven central to this type of learning.  In preliminary studies, we altered the ability of zebrafish to learn by classic conditioning by treating them with toxins during embryogenesis.  Since cocaine is a more potent and reliable stimulus than natural stimuli to induce this type of learning, we use it as a primary stimulus in adult behavioral tests.  We found that embryonic exposure to cocaine increases behavioral response to it later, while heavy metal treatment (cadmium) lowers drug responsiveness later.  Given the importance of monoamines in this type of learning, we are testing the hypothesis that these toxins modify gene expression in the monoaminergic neural pathways in opposite ways during embryo-genesis.  We will also test the hypothesis that epigenetic modification of chromatin underlies the basis for alteration of classic conditioning resulting from embryonic treatment of zebrafish with cocaine or cadmium.
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