The neocortex is the part of the brain that is involved in perception, cognition, and volitional motor control. In mammals, the neocortex is a highly dynamic structure that has been dramatically altered within an individual’s lifetime and in different lineages throughout the course of evolution. These alterations account for the remarkable variations in behavior that species exhibit. Because we cannot study the evolution of the neocortex directly, we must make inferences about the evolutionary process from a comparative analysis of brains, and study the developmental mechanisms that give rise to alterations in the brain. Comparative studies allow us to appreciate the types of changes that have been made to the neocortex and the similarities that exist across taxa, and ultimately the constraints imposed on the evolving brain. Developmental studies inform us about how phenotypic transitions may arise by alterations in developmental cascades or changes in the physical environment in which the brain develops. We focus on how early experience shapes the functional organization and connectivity of each individual’s brain and behavior to be uniquely optimized for a given sensory milieu. Such plasticity plays an integral role in shaping the brains of normal individuals. Changes in sensory input that occur early in development leads to dramatic changes in both the normal organization and connections of the neocortex as well as in sensory mediated behavior. Studies have also demonstrated that enhanced sensory experience that occurs during critical periods of development has a profound effect on the resultant organization and connectivity of the neocortex. In our experiments, we examined the specific types of alterations that occur when individuals develop with lost or enhanced sensory inputs in both experimental and natural settings. Because all aspects of complex social experience including parental rearing and sibling interactions are mediated by our sensory systems, it follows that these types of complex patterns of sensory inputs are fundamentally important for shaping both the organization and connectivity of the neocortex. In turn, the ultimate behavior generated by the neocortex will be highly adaptive for the context in which the individual develops.
 
About the Speaker:

Leah Krubitzer is currently a professor in the Department of Psychology and Center for Neuroscience at the University of California, Davis. She received a BS at Penn State University in Communication Disorders and a PhD in Psychology at Vanderbilt University, Nashville Tennessee. Her graduate work, under the mentorship of Dr. Jon Kaas focused on the evolution of visual cortex in primates. Her interest in the evolution of the neocortex was extended in her postdoctoral work at the University of Queensland, Australia to include a variety of mammals such as monotremes and marsupials. While in Australia she performed comparative analysis on the neocortex of a variety of different species and to date has worked on the brains of over 45 different mammals. Her current research focuses on the impact of early experience on the cortical phenotype, and she specifically examines the effects of the sensory environment on the development of connections, functional organization and behavior in normal and visually impaired mammals. She also examines the evolution of sensory motor networks involved in manual dexterity, reaching and grasping in mammals. She received a MacArthur award for her work on evolution. 
                   
Return to Schedule