I will continue our work on lesion-induced synaptogenesis in the hippocampus of the adult rat. Electron micrcoscopic analysis will be carried out to determine the number of synapses contributed by the residual afferents which sprout and replace those lost. Correlative electrophysiological experiments are planned to eucidate the functional characteristics of the new circuitry. In addition, we will continue our experiments on axon regeneration in the adult CNS. BIBLIOGRAPHIC REFERENCES: Goldowitz, D., White, W., Steward, O., Cotman, C., and Lynch, G. Anatomical evidence for a projection from the entorhinal cortex to the contralateral dentate gyrus of the rat. Exp. Neurol., 1975, 47, 433-441. Drucker-Clin, R.R., Spanis, C.W., Cotman, C.W., and McGaugh, J.L. Changes in protein levels in perfusates of freely moving cats: Relation to behavioral state. Science, 1975, 187, 963-965.