Wilczynski
Lab
Neuroethology of Aggression
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Wilczynski
Lab Neuroethology of Aggression
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| Individuals vary
greatly in their aggressiveness. This is due to a variety of interacting
factors, including hormonal state and past experience. The Wilczynski Lab is now
investigating these interacting factors in order to better understand how
experience and hormonal state mutually influence each other, and how both
contribute to influencing the limbic centers of the brain as these centers
control aggression and other types of social behavior. The green anole lizard (Anolis
carolinensis) is the model animal for this project. |
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Research
in this area focuses
on investigating the plasticity in aggression displayed by green anole
lizards. The research seeks to understand how experience with aggression
changes an individual’s aggressive behavior to familiar and to
unfamiliar challenges. Using video presentations, we have shown that over
several days of successive aggressive interactions males first increase
then gradually habituate to a familiar challenger. This experience,
however, results in males being much more aggressive when a novel intruder
is introduced into their territory. Both androgens and stress hormones
change during the successive aggressive interactions. Current work
investigates the possibility that the hormonal changes triggered by the
aggressive interactions are important for the behavioral changes that
occur with aggressive experience.
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| Series
of photographs above show body color changes in a male lizard triggered by
stress hormones. Colors from top to bottom indicate increasing levels of
stress hormones. Graph at right shows changes in aggression during daily
interactions with a video of a displaying lizard vs. a control video. On
the test day, animals with aggressive experience are more aggressive to a
novel challenge.
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| Research
also targets possible sites of neural plasticity that might underlie the
behavioral plasticity that aggressive social interactions cause. We have
used histochemical staining for the enzyme cytochrome oxidase as an
anatomical marker of functional differences in limbic system brain regions
as a result of social status (dominant or subordinate) or as a result of
repeated aggression interactions with another individual. |
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| Photo shows a cross section through a lizard forebrain stained for cytochrome oxidase. |
Selected Publications
Yang, Y.-J., S. M. Phelps, D. Crews, & W. Wilczynski (2001) The effects of social experience on aggressive behavior in Anolis carolinensis. Ethology, 107: 777-794.
Yang, E. J., and W. Wilczynski (submitted)
Relationships between hormones and aggressive behavior in green anole lizards:
An analysis using structural equation modeling. Horm. Behav.
