Date of Award

Spring 5-2017

Degree Type


Degree Name

Doctor of Philosophy (PhD)



Committee Chair

David Echevarria

Committee Chair Department


Committee Member 2

Francisco Gonzalez-Lima

Committee Member 2 Department


Committee Member 3

Alen Hajnal

Committee Member 3 Department


Committee Member 4

Donald Sacco

Committee Member 4 Department



With the ever-increasing aging population, neurodegenerative diseases such as Alzheimer’s disease are becoming more prevalent. Owing to such increases in age related cognitive decline, the need for research into new, effective treatments is more imperative now than ever. The zebrafish is an excellent animal model that can be used to study the potential pharmacological effects of novel cognition-centric treatments. However, more needs to be known about the species and its ability to learn, remember, and the effects certain drugs have on behavior. In this dissertation, I aimed to better understand zebrafish cognition through the testing of three conditions: a known cognitive enhancer (methylene blue; MB), a known inhibitor of memory (scopolamine), and beaker stress, a novel paradigm that will further our understanding of stress on cognitive tasks. Three learning tasks (T-maze, object recognition, and escape learning) were used to elucidate the effects the three conditions had on various types of learning and memory. MB was shown to significantly improve performance in the T-maze when compared to scopolamine-exposed fish. Beaker stress had no significant effect on T-maze performance. In the object recognition task, MB and beaker stress fish exhibited a significant preference for the novel object, thus showing the intended learned behavior. In escape learning, MB exposed fish spent significantly more time away from the aversive stimulus, thus exhibiting learning of the escape response. Scopolamine-exposed fish exhibited a significant lack of learning as the exposed fish spent significantly more time near the aversive stimulus. Beaker stress exposed fish did not show any significance of learning the behavior in the escape learning task. It can thus be concluded that MB enhanced learning across all learning tasks. Scopolamine induced amnesia-like effects across all learning tasks. Beaker stress had differing effects dependent upon the learning task. These findings are important in allowing the zebrafish to be used more fully in AD research specifically in regards to screening for new treatments such as MB. The next steps of this project are to determine whether MB has an effect on scopolamine-exposed fish and to further understand the effects of stress on different styles of learning