Space radiation can be detrimental to the whole body and can produce oxidative stress in specific areas in the brain. Research has shown that radiation affects the hippocampus, which is responsible for relational/contextual types of learning and memory. Spatial learning and memory is one type of relational learning that is easy to study in animals. The water maze is a test that requires the animal to use spatial navigation skills to find a submerged (hidden) platform in a pool of water. Disease and injury that affect the hippocampus result in spatial learning deficits and altered search strategies in the water maze. Our laboratory has previously shown that pomegranate juice, which has high levels of anti-inflammatory and anti-oxidant polyphenols, can reduce Alzheimer’s-like neuropathology and improve spatial learning in transgenic mice. A discriminate function analysis demonstrated that experimental group predicted search strategy use, correctly identifying 66% by gender, 61% by irradiation status, and 54% by diet. Furthermore, cell counts showed that females had more cells in the subgranular layer of the hippocampus, and that a higher cell count in the dentate gyrus was significantly correlated with increased use of a focal incorrect search strategy. These data demonstrate that the water maze can generate a much richer data set than simple escape latency and/or swim distance, and that different experimental groups can achieve similar performance on this test by the use of a number of different search strategies.

LLU Discipline

Clinical Psychology




School of Behavioral Health

First Advisor

Hartman, Richard E.

Second Advisor

Haerich, Paul

Third Advisor

Vermeersch, David A.

Degree Name

Doctor of Philosophy (PhD)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Maze tests; Animals -- Psychological testing; Spatial behavior in animals; Animals -- Effect of Radiation on; Maze learning -- radiation effects; Hippocampus -- physiology

Subject - Local

Pomegranate juice; Relational learning; Memory; Water maze tests; Polyphenols; Discriminate function analysis



Page Count


Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives