Neuroethology: A Meeting of Brain and Behavior

Neuron, Vol. 21, 981–989, November, 1998, Copyright 1998 by Cell Press Neuroethology: A Meeting of Brain and Behavior Meeting Report John E. Spiro* and Stephanie A. White Department of Neurobiology Duke University Medical Center Durham, North Carolina 27710 highly differentiated to perform a specific function. Be- cause neural mechanisms, especially at the cellular and small circuit level, have proven to be remarkably con- served throughout evolution (fish as well as primates have a vestibulo-ocular response [VOR], for example), it makes good sense to study highly specialized and often less complex nervous systems to learn general principles. At the same time, the difficulties with such animals can be substantial: the anatomy, physiology, and genetics are usually incompletely described com- pared with more “standard” laboratory animals such as mice and rats, and obtaining and breeding them is often challenging. As we highlight in this review, however, a careful analysis of natural behavior afforded in these “specialist” species can help to define the problems that more generalized brains need to solve, and can therefore serve as a strong guide for focusing cellular- level questions of broad interest. Neuroethology has historically emphasized a compar- ative approach to understanding brain function, and the strength of this strategy was readily apparent from many of the presentations at the meeting. In addition, the emergence of new technologies, especially techniques for chronic recording and imaging in relatively intact nervous systems, are enabling researchers to under- stand the neural basis of behavior under natural condi- tions, which to many neuroethologists is a long-term goal. The subject diversity of the meeting was enormous: what other meeting can boast a talk on in vivo imaging of dendritic calcium dynamics followed by one on elephant pheromones? In an attempt to convey the range of sub- jects discussed at the meeting and to capture the excite- ment of recent developments in neuroethology, we dis- cuss several presentations, broadly organized by some general themes that emerged: sensitive periods and cir- cuits for learning, synaptic plasticity in the adult CNS, and the reciprocal relationship between genes and so- cial behavior. Furthermore, we highlight results obtained using novel tools, both man-made (multi-electrode re- cording arrays) and biological (cone snail toxins). Finally, we cover two special symposia, one honoring the Soci- ety’s Young Investigators and one in memory of Walter Heiligenberg. Introduction On August 23–28, 1998, a diverse group of approximately 600 people interested in animal behavior and the ner- vous system gathered on the campus of the University of California at San Diego, in La Jolla, California, for the Fifth Congress of the International Society for Neuro- ethology. Continuing the spirit of previous congresses held in Tokyo (1987), Berlin (1989), Montreal (1992), and Cambridge (1995), local organizer Bill Kristan and other members of the planning committee, headed by Joa- chim Pflueger, combined plenary sessions, symposia, poster sessions, and social events, creating a program that encouraged lively and informal discussions. New forums for scientific exchange included a Young Investi- gator Award symposium, which allowed this year’s four awardees to present their work to the entire congress, and informal ad hoc talks, a refreshing venue for mate- rial too current to have been included by the abstract deadline. What exactly is neuroethology? The field emerged out of traditional ethology, or the study of animal behavior (usually in the animal’s natural environment), which was championed by the likes of Lorenz, Tinbergen, and von Frisch. Neuroethology evolved when ethologists, in col- laborations with physiologists and anatomists, delved into the neural bases of the behaviors they were study- ing. Assuming that a good working definition of a mod- ern neuroethologist includes anyone who attended the recent meeting, the definition has expanded to encom- pass all those interested in understanding the link be- tween brain and behavior, including those taking more traditional top-down approaches (i.e., study a natural behavior in detail and then try to uncover its neural underpinnings) and those taking more bottom-up ap- proaches (identify an interesting neural phenomenon in a reduced preparation and then try to understand how it contributes to behavior). In an effort to link neural events with behavior, neuro- ethologists often rely on experimental animals, both ver- tebrates and invertebrates, that are highly specialized to perform specific behaviors, such as electric fish (elec- trolocation), bats (echolocation), owls (sound localiza- tion), songbirds (vocal learning), and bees (navigation to food sources). Because these animals have evolved under selection pressures to perform particular behav- iors very reliably (for example, owls hunt at night and can localize sound with extreme accuracy), they allow the experimenter to explore behavior in a quantitative fashion and to investigate a nervous system that is often * To whom correspondence should be addressed (e-mail: spiro@ neuro.duke.edu). Sensitive Periods and Circuits for Learning Sensitive and/or “critical” periods, which are very com- mon in sensory system development, are also a key part of behavioral development. In some cases, the neural mechanisms underlying sensitive periods are becoming understood. Recent results show that critical periods are less “hard wired” and more experience dependent than had been previously believed. Furthermore, path- ways involved in learning in the young animal may be involved in the maintenance of stable adult behaviors. Human Language Learning P. Kuhl (University of Washington, Seattle) demon- strated how very early language exposure leads to the formation of perceptual maps in human infants that then