Breedlove Jordan Lab

Damian Zuloaga


I am currently a graduate student, in the Behavioral Neuroscience subdivision of Psychology. I received a BA and MA in psychology at San Diego State University. My hobbies include skateboarding and stereology and I am interested in the role of hormones and hormone receptors in CNS plasticity and behavior.

Recently my research has been focused on two main topics: (1) the effects of castration of C57BL6 mice in adulthood on soma size and dendritic arborization in neurons of the spinal nucleus of the bulbocavernosus (SNB) and (2) sensorimotor and anxiety behaviors in animals with the testicular feminization mutation (TFM) that lack functional androgen receptors (AR).

Topic 1: SNB soma size and dendritic arborization in adult castrated C57BL6 mice

In rats evidence suggests that castration in adulthood results in a shrinking of the dendritic trees of the SNB. However, in mice it is unclear as to whether this phenomenon occurs. SNB dendrites were found to shrink in one strain of mice, but not in another in two different studies. Therefore, we decided to test whether SNB dendritic trees would shrink following castration in adulthood in a different and commonly used strain of mice for transgenic models, the C57BL6 mouse. It is also unclear as to whether the SNB soma size in this strain will also shrink following castration, so this is also under investigation.

Topic 2: TFM Behavior

Animals with the testicular feminization mutation lack functional ARs and are therefore an excellent model for exploring the role of AR in behavior. Sensorimotor Gating: Prepulse Inhibition (PPI) is a common measure of sensorimotor gating in human and rodent models. PPI is determined by the fast muscle twitch response to a loud acoustic stimulus that is preceded, by approximately 100ms, by a weaker acoustic stimulus or "prepulse". The prepulse should permit the subject to anticipate the loud pulse, and consequently startle less severely. Sensorimotor gating is necessary to filter sensory, motor, and cognitive information and is reduced in people with schizophrenia compared to normal controls. Recent studies have shown that both estrogen and testosterone administration can affect sensorimotor gating in both humans and rodents. My goal is to test the role of the androgen receptor in sensorimotor gating using mice and rat TFM models. Anxiety: Testosterone and estrogen are also shown to affect anxiety related behavior in rats and humans. However, the role of AR in anxiety is less understood. Therefore I am currently investigating the role of AR in anxiety by exposing TFM rodents to a battery of anxiety tests.

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