We propose to use a modified high-resolution 2-deoxyglucose (2DG) technique, computer-controlled sensory stimulation and two or more neuroanatomical labels to examine the functional organization of the cerebral cortex. The whisker related barrel field of rodents will be studied. Whisker columns from available materials show patches of dense label extending throughout all cortical laminae. These patches have smaller diameters than barrels and are variable in their position and size within a barrel from one hemisphere to another. We will characterize patterns of cortical labeling using computer- controlled patterned stimulation of one or more whiskers. Our techniques, which depend on the CORE, allow the construction of complete maps of the stimulated and surrounding portions of the barrel field, so that we can accurately contrast the metabolic responses of one cortex with another. Our first hypothesis, based on 2DG data from behaving animals, is that the subcolumnar patches or mini-columns we observe are established by """"""""connectionist"""""""" rules. We will test this by presenting identical patterns of stimulation to homotypic whiskers in a number of individuals and assessing the degree of individual variation in cortical labeling patterns with respect to the stimulated barrel column. Our second hypothesis, based on pilot experiments, is that there are localized """"""""integrator"""""""" zones outside the principal whisker columns which respond specifically to multiwhisker stimuli. We will test this by comparing the effects of two different 2-whisker stimulation strategies. Our third hypothesis, based on electrophysiological results is that chronic sensory deprivation due to selective whisker trimming from birth will significantly alter the normal cortical 2DG labeling patterns. The data from these studies should provide a functional and an anatomical context for understanding the mechanisms by which the stereotyped cytoarchitectonic territories of barrel cortex are parcelled into smaller functional domains.
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