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By combining functional MRI with structural MRI, we can make measurements of the living human brain. My focus is on individual brains. Like faces, each brain is unique. There are common features, but the detailed pattern of folds and crevises, the basic shape and size, and the functional architecture all vary across individuals. With modern MRI techniques, we can measure each brain separately and find the differences as well as the generalizations.

I have made some basic measurements in the occipital lobe of the human brain. With our combined structural/functional techniques, we have replicated and extended various measurements that previously required post-mortem dissection. The results of this study are summarized in this paper. One of the more interesting findings is that the sizes of the early visual areas (V1, V2 and V3) vary by up to a factor of three across individuals. This individual variation is remarkable, especially given that the total brain size varies by only a fraction of that (about 15%). Thus, an individual with large visual areas must be lacking in some other brain regions, and vice-versa. (In case you were wondering- I have a particularly small visual cortex. :) An interesting question that arises is: What are the behavioral consequences of these large differences in cortical surface area? Rob Duncan and Geoff Boynton have made some progress addressing this question.

Summary figures from visual field representations paper

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