The ability to learn new spatial information about the visual environment involves specific brain regions. One important area is the hippocampus which in turn receives sensory input from cells of the lateral dorsal thalamic nucleus (LDN). The focus of this award to Dr. Sheri Mizumori is to study the functional contribution of the lateral dorsal thalamus to spatial information processing. Activity in cells of the LDN will be of these cells is increased when the head is aligned along particular directions in horizontal space, independent of location in the environment. The visual properties of the head direction cells will be studied in several ways. Whether or not manipulation of the visual environment can change the activity of these cells will be tested. The experience- dependent nature of LDN head direction cells will be evaluated by examining the accuracy during acquisition of a maze task. The hypothesis will be tested that visual integration in the LDN is accomplished by subdivisions of the hippocampal formation. The effect of destroying the LDN on spatial and non-spatial learning will also be investigated. The results of this research will contribute to basic knowledge about the dynamics and organization of visual spatial processing.
