University of California, San Diego
The Department of Psychology is Honored
to Present a Talk by
David Crews
University of Texas at Austin
"EVOLUTION OF NEUROENDOCRINE MECHANISMS CONTROLLING BEHAVIOR"
Presented on June 2, 2005
Location: The Crick Conference Room
Mandler Hall, room 3545
- Abstract:
- The whiptail lizards provide a unique model system with which
to study the evolution of brain mechanisms as both the ancestral (sexual)
and descendant (parthenogenetic) species still exist. The parthenogenetic
whiptail also enables us to avoid the two major confounds in sex
differences research, namely the presence of two types of individuals
(males and females) that differ both genetically and hormonally. The
parthenogenetic species reproduce clonally and consist only of female
individuals, yet they display alternately both female-like and male-like
pseudosexual behavior. Thus, it is possible to examine simultaneously
within the "same" brain (i.e., the same genome) the neural circuitry
underlying male and female sexual behavior. This snapshot of evolution
also enables us to see how the neuroendocrine mechanisms controlling
mounting behavior can change. In this instance in males of the ancestral
sexual species testicular androgens control sexual behavior whereas in the
descendant parthenogenetic species male-like pseudocopulatory behavior is
controlled by progesterone secreted by the ovaries following ovulation.
This shows how a new hormone can be co-opted to trigger a neuroendocrine
mechanism controlling reproductive behavior. This work has also revealed
that progesterone is important in regulating sexual behavior in male
vertebrates, including mammals.
- About the Speaker:
-
My research has focused on problems in reproductive biology,
principally on the development and function of sex differences. The
research strategy employed has been to identify important problems in
behavioral biology and then find a species that allows me to address that
problem in a unique way. Experience has taught me that Nature provides all
of the experimental preparations required. Conventional animal models are
also utilized when they enable me to extend findings to the mammalian
condition, or provide unique preparations with which to study
neuroendocrine mechanisms.
All of my research uses a comparative, interdisciplinary approach that combines and integrates the molecular, cellular, physiological, morphological, organismal, ecological, and evolutionary levels of analysis. The research is conducted both in the laboratory and in the field to illustrate how the causal mechanisms and functional outcomes of reproductive processes operate at each level of biological organization while, at the same time, illuminating the relations among the levels. It has been my experience that field and laboratory studies are complementary; the field has proven to be a valuable testing ground for adaptive functions, whereas the laboratory is the only possible arena for determining many of the physiological and molecular bases of phenomena observed in the field.
For More Information About This Speaker:
- http://www.utexas.edu/research/crewslab/
The website of Dr. Crews' lab.
- http://www.utexas.edu/research/crewslab/curriculum_vitae.htm
Dr. Crews' curriculum vitae.
