Deficits in verbal and visual processing of objects, features, and categories, and their neuroanatomic correlates, will be studied in human subjects. The principal issues will be (a) to what extent or at what level are visual and verbal object processing distinct, (b) for visual processing, what are some of the features and combinations of features that provide a basis for object recognition; (c) for verbal processing, what are the features, categories, and supraordinate relations of items; (d) what types of information (e.g., featural or categorical) are relayed between the visual and verbal systems, (e) what role does category-level information have in regulating or gating information flow; and (f) what re the neuroanatomic correlates of the component processes that are identified behaviorally. In addition to behavioral studies of patients with static lesions, several unique patient populations and methodologies will be used: surgical lesions, studied pre- as well as post-operatively; direct cortical electrical interference, which allows repeated, temporary """"""""lesioning"""""""" of multiple cortical sites in the same individual; and ultimately direct cortical electrical recording and regional cerebral blood flow measures using functional MRI. Results will be analyzed within standard and computational approaches. These data should be important for understanding the normal processes and structures involved in the language and visual systems for representing object information, and for helping to diagnose and to remediate the effects of brain injuries upon these functions.
