Sex differences in brain and behavior are widespread across vertebrates. Birds exhibit remarkable examples of these types of parallels between structure and function. For example, only male zebra finches sing, and the brain areas and muscles controlling the learning and production of these vocalizations are greatly enhanced in males compared to females. These sex differences are permanently established in development. Some songbirds, unlike zebra finches, change their songs seasonally. In a number of these species, the brain regions exhibit changes in neuron loss and incorporation across these periods. The mechanisms involved in these types of sexual differentiation and adult plasticity are described; they likely involve both steroid hormones and genetic (protein) factors. The strength of the relationships between morphology and behavior, as well as many other factors, has made birds outstanding models for the investigation of numerous functions. These include the mechanisms regulating vocal learning, auditory perception, neurogenesis, and cell survival. The lessons learned have broad implications for health-related processes and basic biological principles.
Table of Contents
2. Song and Song Learning
2.2 Structures Controlling Song Learning and Production in Songbirds
2.3 Relationships Between Structure and Function: Sex Differences in the Song Circuit
2.4 Mechanisms Regulating Sexual Differentiation of the Song System
2.5 Relationships Between Structure and Function: Adult Plasticity in the Song Circuit
2.6 Structures Controlling Song Learning and Production in Other Orders of Birds
3. Other Social/Reproductive Behaviors
4. Conclusions and Ideas for Future Directions
About the Author(s)Juli Wade
, Michigan State University
Juli Wade is professor and chair of the Psychology Department at Michigan State University. She also holds an appointment in the Zoology Department and is a member of the Neuroscience Program at MSU. She received her Ph.D. from the University of Texas at Austin in 1992, and then did a postdoc with Art Arnold at UCLA before beginning her faculty position at Michigan State in 1995. She received the Teacher-Scholar award from MSU in 2002. Dr. Wade's area of research involves the mechanisms regulating development and adult maintenance of sex differences in brain and behavior. Members of her lab used two model systems for this work - zebra finches and anole lizards.