<b>Complex Systems Seminar</b><br>How Does Evolution Build a Complex Brain?<br><b>Speaker: Professor Leah Krubitzer (UC Davis)</b></br>

The neocortex is the part of the brain that is involved in perception, cognition, and volitional motor control. In mammals it is a highly dynamic structure that has been dramatically altered in different lineages throughout the course of evolution, and 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 from comparative analysis of brains, as well as developmental mechanisms that give rise to aspects of the phenotype.  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 evolving brain. Developmental studies allow us to appreciate how phenotypic transitions may arise by alterations in developmental cascades. Both genes and the sensory environment in which and individual develops contribute to aspects of the phenotype and similar features, such as the size of a cortical field, can be altered in a variety of ways.  Although both genes and the laws of physics place formidable constraints on the evolution of the neocortex, mammals have evolved a number of mechanisms that allow them to loosen these constraints and often alter the course of their own evolution.