Much of the pathophysiology of Parkinson's disease and other movement disorders has been localized to the basal ganglia, especially striatum. The proposed experiments will investigate the anatomical substrate of functional activity in striatum. Normal striatal function is dependent upon widespread cortical innervation of an intrinsic chemoarchitectonic organization of """"""""patches"""""""" in a surrounding """"""""matrix"""""""" of neurochemicals and receptors, some known to be deficient in movement disorders. However, little is known about the functional role of corticostriate activity within these compartments, except that it may integrate information to select and guide movement. In recent studies using 14C deoxyglucose and somatosensory stimulation, this laboratory has shown that the striatum contains a complex somatotopic map. Three-dimensional analysis reveals that representation of each body region shifts relative to others, in the anteroposterior plane, suggesting that the map is combinational. Another important characteristic of the map is that both sides of the body are represented on each side of the striatum. This presents a new picture of striatal organization. The goals of the present project are 1) to determine the spatial organization of projections from somatosensory cortex to striatum and how that organization relates to the functional activity we have already mapped, 2) to determine the correspondence between sensory and motor cortex projections in striatum and 3) to determine how the body may in striatum is related to its known chemoarchitecture. Methods will include 14C deoxyglucose autoradiography; anterograde anatomical tract tracing with Phaseolus vulgaris-leucoagglutinin, which allows small injection sites and high resolution of axon terminals, and 3H amino acids; electrophysiological recording and stimulation in cortex to physiologically identify the tracer injection sites; mu opiate receptor autoradiography; and tactile stimulation of different body regions, in rats. The hypotheses are that the functional map we described reflects the anatomical projections from cortex, and that the map is principally within the """"""""matrix"""""""" compartment, thus defining some of its other inputs and neuroactive substances. The proposed studies swill provide new information about the anatomical, spatial organization of the striatum, at higher resolution than has previously been available. A functional probe of that organization will be useful for future studies of striatal neurochemistry and pathology.
