The role of the limbic system, particularly hippocampus, in spatial memory is investigated. The first series of experiments establishes an animal model of working memory for spatial locations and describes the memory in terms of capacity, accuracy, interference, decay, primacy, recency, and release from proactive inhibition. The next series of experiments examines the role of the hippocampus in spatial memory by placing discrete lesions in the hippocampus itself or in its extrinsic fibre connections with other brain areas. Related experiments are proposed with other brain structures, namely dorsomedial thalamus, frontal cortex, parietal lobe, and caudate nucleus, to establish the specificity of the hippocampal function and its dissociation from other brain areas. The goal of these experiments is to describe more fully the particular behavioral changes that result from brain lesions in each of these areas, and to provide information about the functional neuroanatomy of each of the structures studied. The final series of experiments examines the behavioral correlates of hippocampal nerve cells during performance of spatial tasks, and will analyze the results in terms of the spatial characteristics of the receptive fields of these nerve cells. BIBLIOGRAPHIC REFERENCE: Olton, D.S., and Samuelson, R.J. Remembrance of places passed: Spatial memory in rats. Journal of Experimental Psychology: Animal Behavior Processes, 1976, 2, 97-116.