The application outlines a continuing research plan aimed at elucidating the neuroanatomical organization of the mesocortices in the monkey. The mesocortices represent the dominant cortices on the medial surface of the cerebral hemisphere and constitute the limbic lobe. The cingulate gyrus, parahippocampla gyrus, temporal polar area and posterior orbitofrontal area are major elements. Three aims are specified, these entail: (1) experimental neuroanatomical studies on the connections of the mesocortices using anterograde and retrograde tracing techniques; (2) reinnervation studies in temporal lobe structures, and; (3) double retrograde tracing studies using fluorscent dyes to explore axon collateralization in mesocortical connections. Connectional studies will focus on the uninvestigated bridging parts of the limbic lobe, including the retrosplenial, retrocalcarine, perirhinal and temporal polar mesocortices, reinnervation studies will focus on the lateral amygdaloid nucleus and the anterior parahippocampal area (entorhinal cortex), while double labeling studies will concentrate on the cingulate and posterior parahippocampal mesocortices. The program has combined relevance to both basic neuroscience and clinical neuroscience. The mesocortices are intermediate from both connectional and cytoarchitectural viewpoints, sharing the feature of interconnecting the association cortices and the limbic system. This interaction, when disrupted, often leads to debilitating disorders of emotion, attention and memory in man, as well as in non-human primates. The reinnervation studies focus on temporal areas that are involved frequently in head trauma, and may be relevant to the post-traumatic alterations in behavior seen frequently in the clinic. To date there is adequate reason to believe that many types of reinnervation occur in response to temporal lobe injury. The aims are interlocked and conducted against a background of 12 productive years studying the mesocortices in the primate.