Functional Imaging of the Human Brain: A Window into the Architecture of the Mind

Abstract

The last 20 years of brain imaging research has revealed the functional organization of the human brain in glorious detail, including dozens of cortical regions each of which is specifically engaged in a particular mental task, like recognizing faces, perceiving speech sounds, and understanding the meaning of a sentence. Each of these regions is present, in approximately the same location, in every normal person. This initial rough sketch of the functional organization of the brain counts as real progress, giving us a kind of diagram of the major components of the human mind. But at the same time, it is just the barest beginning. Really what our new map of the human brain offers is a vast landscape of new questions. In this talk I will first broadly survey some of the most widely replicated functionally distinctive cortical regions, and then describe ongoing work into three such questions. First, in light of widespread findings that functionally specific cortical regions contain information about “nonpreferred” stimuli, do some patches of cortex really play a highly specific causal role in processing just one class of stimuli? Second, how does all this complex structure, that is so similar across subjects, arise in development? I will discuss the developmental origins of cortical specificity, including a new finding of what appears to be a fusiform face area in the ventral visual pathway of congenitally blind people. Third, why do we have the particular functionally specific cortical regions we do, and apparently not others, and why, from a computational point of view, is functional specificity a good design feature for brains in the first place?