PROJECT SUMMARY Because of its close phylogenetic relationship to the human, the non-human primate (NHP) brain holds enormous potential for understanding structure, function, development and pathology of the human brain. However, many obstacles impede studies of NHPs (among these, significant logistic, ethical, and financial burdens). The Department of Neuroscience at Yale University houses a unique collection of brain tissue from NHP macaques, ranging in age from embryonic to adult, which was generated over almost five decades in the laboratories of Dr. Pasko Rakic and the late Dr. Patricia Goldman-Rakic. The collection includes sets of slides with: (1) [3H]thymidine-labeled serially cut brains for cell birth dating; (2) brains labeled with tritiated amino acids for tract tracing; (3) brains from monkeys with enucleations and selected cortical lesions; (4) brains from prenatally X-irradiated and ultrasound-exposed monkeys sacrificed postnatally; (5) EM blocks from multiple brain regions of fetal and postnatal monkeys; and, added in the last year, (6) histo- and immunohistochemically processed brain tissue and (7) unprocessed NHP brain tissue blocks. While MBR’s overreaching Specific Aims remain the same, proper adjustments have been made, conducive to support ongoing research projects and to grow MBR in scope to accommodate new ones. This renewal proposes: 1) To continue to inventory, catalogue, restore and add materials to MBR Collections 1 to 4. 2) To histo- and immunohistochemically process tissue to expand collection 6 and to add unprocessed tissue blocks to collection 7. 3) To continue to advertise and disseminate NHP brain information. 4) To continue to facilitate use of the resource. A main purpose of the current renewal application is maintain MBR’s operations and to facilitate its growth by funding the processing of tissue for different neuronal and non-neuronal markers (in M & F specimens of 7 developmentally distinct age groups) to be added to collection 6. In addition, brain tissue blocks viable for different treatments will continue to be added to collection 7. The grand objective of this grant remains the same, to make these unique collections an international research resource that is readily available to the neuroscience community at-large. If funded, MBR will continue to permit and foster NHP brain research without requiring additional animal sacrifice. This avoids costly duplication of experiments and unnecessary use of animals.