in the cortex in response to barbsbars, to edges and differet cells will respond to edges of different orientation. vertical, horizontal or oblique. so there's a tremendous specificity in the whole transformation of having circular fields to linear is a major operation that the brain performs. you can imagine at later stages you can put lines together to have corners, ultimately to have faces. so this is the beginning of how the brain reconstructs a visual image. >> charlie: tell me about how you have begun to understand a focus on the localization of function. >> well, our work builds on not the prior work using behavioral measures. so we're interested in face perception. one of the reasons we chose to work with face perception there were lots of reasons to think that the brain would have special machinery for processing faces. so if we show that movie, you'll see in the display that when a face presented upside down you can't tell what it is. th is charteriicf faces in particular. you don't see it for other kinds of stimuli. it's perfectly easy to recognize a chair or a dog or a tree