Dr. Heather J. Rhodes
B.S. in Animal Physiology and Neuroscience from University of California, San Diego, 1996
Ph.D. in Neurobiology from Duke University, 2003
- Introduction to the Science of Biology (BIO 150)
- Cellular and Molecular Biology (BIO 201)
- Human Physiology (BIO 335)
- Animal Physiology (BIO 334)
I am interested in understanding how neural circuits produce perceptions and behaviors. In my current research I study the vocal circuit of the African clawed frog (Xenopus laevis). Xenopus produce rhythmic vocal patterns using a type of neural circuit called a central pattern generator (CPG). CPGs are neural circuits that are capable of generating a rhythmic output without any rhythmic input; they are essentially pacemakers. They are used to control a wide variety of rhythmic behaviors in other animals, such as walking, swimming, and breathing. CPG circuits can take many forms and we don't yet understand the structure or function of the Xenopus vocal CPG, but that's one of the goals of my research.
The CPG in the Xenopus vocal system is cool in a couple of ways. First, we can activate it in an isolated brain preparation to evoke rhythmic neural activity patterns called fictive vocalizations (like vocalizations without a voice). Being able to reproduce the neural patterns associated with vocalizations in an isolated brain allows us to physically and pharmacologically manipulate the neural circuit and see how it affects vocal production.
Second, the Xenopus vocal circuit is altered by hormones. Male and female frogs produce different calls, and by changing hormone exposure you can change the types of vocal rhythms the brain produces. For example, giving a female testosterone will cause her to produce male-like vocal patterns. I'd like to know more about how hormones alter the neural circuits to produce these effects.
I am also interested in understanding what cues naturally activate the vocal CPG to cause the animals to start calling. What external stimuli or internal hormonal cues trigger vocal behavior and how?
The techniques I use in my lab include electrophysiology (recording the electrical potentials produced by one or more active neurons in brain tissue), histology (examining anatomical features of neurons), immunocytochemistry (using antibodies find the locations of neurotransmitters and other chemicals in the brain), and behavioral studies (using automated underwater microphones to monitor frog vocal behavior).
If you are interested in my research, read the publications listed below and also look up papers by Ayako Yamaguchi (my former mentor) and Darcy Kelley both of whom also study the Xenopus vocal system.