The goal of the present research is to use Functional Magnetic Resonance Imaging (fMRI) of the brain to discover the functional components of visual recognition. This application takes as its starting point the recent discovery of an area in extrastriate cortex which is specifically involved in the analysis of visual object shape. The experiments described here will test subjects in an MRI scanner on a wide variety of visual stimuli and tasks in order to 1) zero in on the specific processes that take place in this cortical area and 2) discover new brain areas specialized for different functional components of visual recognition. Part I will test whether visual recognition of different classes of stimuli (objects, faces, words and biological-motion displays) engage the same or different cortical areas. Two aspects of the experimental design will permit a more precise answer to this question than has previously been possible. First, stimuli will be constructed which control for low-level feature components of complex images. Second, detailed within-subject analyses will allow the investigators to dissociate different functional areas even if the anatomical loci of these areas varies considerably across subjects. In Part II, a more fine-grained analysis of the different components of visual shape analysis will be carried out in an effort to distinguish between cortical areas involved in figure-ground segregation, part decomposition, depth interpretation, and other components of shape processing. The investigators will also look for cortical areas that respond differently to familiar and unfamiliar visual stimuli in order to determine whether visual memories and memory-matching processes are separable from bottom-up stages of visual processing. In order to explore the role of attention in visual object recognition, in Part III the investigators will manipulate the subjects' attention with a variety of tasks to ask whether the shape of an object is analyzed even when attention is focused on 1) the color of the same object, 2) another object in the visual field, or 3) a difficult perceptual task in another sensory modality. Using fMRI imaging in conjunction with carefully-controlled stimuli and tasks to characterize and localize specific visual computations is a new way to exploit the modular structure of the brain to discover the functional components of the mind. The present approach may provide the crucial missing link between the considerable knowledge of the neural basis of vision and the understanding that has been gained from computational and cognitive approaches.
