Analysis of Amygdala Morphology and Neurogenesis in Green Anole Lizard in Breeding Versus Non-Breeding Season

Steroid hormones and their derivatives play a major role in the reproductive system. Studying the effects of the hormones on the brain can lead us to further information regarding the process of the reproductive system. Because the amygdala is responsible for reproductive behaviors, such as copulation, we will use this area of the brain to retrieve desired data. We are examining the relationship between steroid hormone and neuron size, number and neurogenesis in the amygdala. We are using the green anole lizard (Anolis carolinensis) as a model organism to study neurogenesis in the amygdala. Green anoles are seasonally breeding animals and exhibit unique behavioral and physiological differences in the breeding season compared to the non- breeding season. These behavioral differences are likely caused by seasonal changes in circulating steroid hormone levels. Green anoles were caught in natural habitat during the breeding season, transferred to the laboratory, and gonadectomized. A capsule containing either testosterone, estradiol, or left empty was inserted under the anole's skin. The animals were injected with BrdU for three days after the treatment. After one month, brains were collected, sectioned, and placed on slides. BrdU and Hu markers were applied to the slides to display the presence of new neurons. Sections of brain were used to count cell number and soma size were treated with Nissl stain. Measurements were taken using a microscope to examine the sections of brain. We expect to see a decrease in neuron number in the amygdala during the breeding season.