From mice to men: the evolution of the large, complex human brain

摘要

My interest in brain evolution developed because I had the opportunity to study with two outstanding neuro-scientists who studied how brains of different mammals were similar and different. As a graduate student, I worked with Irving Diamond at Duke University where his laboratory studied brain organization and behaviour in such seldom investigated mammals as tree shrews, squirrels, hedgehogs, and opossums. I continued with postdoctoral training at the University of Wisconsin where Clinton Woolsey was describing the organization of sensory and motor areas of neocortex in rabbits, cats, and monkeys. For a while, I concentrated on studies of visual cortex organization in New World owl monkeys. After I was appointed as an associate professor at Vanderbilt University, I was able to gradually expand my research, with the help and leadership of a talented group of graduate students and postdoctoral fellows, to include investigations of the somatosensory, auditory and motor systems. Over time we were able to study these systems in a range of mammals, including a number of species of prosimian and simian primates, as well as study brain material obtained after natural death from apes and humans. We also studied hedgehogs, tenrecs, shrews, moles, rats, squirrels, cats, and tree shrews, but the general goal was to see how brains were similar and different, and use this information to infer the course of brain evolution from early mammals to present-day humans. Like exploring the universe, the task is so enormous that we will never be done, but the fun is in the journey, and we feel that we have made great progress. The future is especially bright, as I started this journey when few methods were available to reveal brain organization and function. Gradually, more-powerful methods emerged, and we now seem to be in an explosion of technical advances. The brief outline of brain evolution that follows will be replaced by a much more detailed description in 10 years.