Recent findings in the field of cognitive neuroscience have suggested that specific brain areas are dedicated to specific human behaviors. The current research examines a different brain-behavior organization in which cognition is supported by an interactive network of brain regions, with many brain regions participating in many behaviors in a graded, dynamic and cooperative fashion. Specifically, the investigators will examine the neural substrates responsible for two behaviors, namely face recognition and word recognition. The proposed research predicts that adult individuals who acquire an impairment in face perception (a disorder known as 'prosopagnosia') due to brain injury will also have problems to varying degrees with the perception of words, and conversely, individuals who acquire an impairment in word recognition (a disorder known as 'pure alexia') due to brain injury will also demonstrate some abnormality in face recognition. Additionally, this research investigates the performance of normal individuals with the expectation that if the right hemisphere is highly specialized for face perception, the left hemisphere will be highly specialized for word perception but that the balance between these two abilities might vary in a complementary fashion across a range of individuals. The investigators will use a combination of behavioral and neuroimaging studies of normal and brain-damaged individuals and use computational modeling tools to test these predictions. Findings from this research will provide support for the claim of partial co-mingling of face and word processing in a shared network as well as the hemispheric cooperation and competition in normal observers and associated individual differences for face and word representation. The empirical behavioral and imaging studies will generate data that guide the development of a computational model of how complex behavior is mediated by the brain and the model, in turn, will inspire further testable predictions of this account.
The critical focus of this research is to explore the correspondences between the brain and behavior with specific emphasis on the nature of the organization of the brain that supports rapid and efficient human behavior. What brain systems enable us to recognize words with such accuracy and speed? Are these the same systems that allow us to recognize faces so well? How do we explain individual differences in the ability to recognize such perceptually challenging visual input? To the extent this research can show how general computational principles lead to well defined functional specializations, it may transform our understanding of the functional organization and specialization in the brain in general. In addition to examining the fundamental mechanisms of visual object recognition and individual differences in normal and disordered visual recognition, the investigators expect that an understanding of the intact system and its breakdown will enable the development of more effective methods for intervention and rehabilitation for patients who suffer from visual recognition deficits. Finally, the project will contribute to research infrastructure not only by training students and junior investigators but also by disseminating the findings and the computer modeling tools to the broader research community.
