Dr. Russell Fernald is a neuroethologist at Stanford University. Neuroethology integrates brain science with the study of behavior in natural habitats. The goal is to illustrate the interaction among brain, behavior, and environment. Dr. Fernald's long-term work focuses on the African cichlid fish and how its social system regulates not only brain structures, but also bodily functions.
When a male cichlid fish recognizes an opportunity to become the dominant male, his body turns bright colors. The male fish then chases and attacks other male cichlid fish in an attempt to dominate and defend his territory. The physiological color change results from a response in the hypothalamus in the brain. In the cichlid fish, the signaling peptide cells grow eight times larger, sending the brain eight times the signal. The result is an enlargement of the fish gonads, physiologically preparing the fish to spawn with females.
When the cichlid fish loses control of the territory, he loses his bright coloring. Some fish, however, will then go into hiding, turn on the color signals of dominance, and pretend that they are still dominant for a period lasting up to three weeks.
The human brain also contains the hypothalamus. Neuroethologists hypothesize that behavioral responses parallel to those cichlid fish take place in humans, beginning at puberty. Dr. Fernald's research illustrates one example of how animal and human brains receive and translate signals from the social environment, resulting in physiological change.
The Fernald lab Web site at http://www.stanford.edu/group/fernaldlab/modelSystem.shtml has information on current research into the behavior of African cichild fish.