Morphological and electrophysiological study of sprouting of corticorubral fibers after lesions of the contralateral cerebrum in kitten.

The appearance of crossed corticorubral projections following ablations of the ipsilateral cortex is shown to result from the formation of new connections and is not due to the preservation of pre-existing bilateral connections. At least some of these crossed projections are collaterals of the pyramidal tract. Post-tetanic potentiation can be demonstrated both intra- and extracellularly following ipsilateral cerebral peduncle stimulation whereas no changes in excitatory postsynaptic potential amplitude are observed following contralateral cerebral peduncle stimulation.