Leah Krubitzer: 2011 Allen Institute for Brain Science Symposium

Leah Krubitzer, University of California, Davis All rodents are not created equal

Dr. Krubitzer highlighted radical differences in cortical organization in the context of animal lifestyles. Rodents, a group of about 2,277 species, comprise 40% of all mammals. And yet so many studies are done on only two species of rodents: the rat and the mouse. By studying several parameters of the brains of these animals Dr. Krubitzer showed how genetic alterations and alterations in sensory-driven activity can drive evolutionary change in the brain. For example, comparison of three types of rats, nocturnal, diurnal, and laboratory, reveals the lab rat has the lowest neural density and the least percent of neurons in its brain tissue. This speaks to the evolutionary change that takes place in brains as needed based on lifestyle. While the trend is towards scaling up the size of the brain in conjunction with a scaling up in body size, this may not be sufficient to increase the number of cortical fields.