Reformation in adult rats of functional septo-hippocampal connections by septal neurons regenerating across an embryonic hippocampal tissue bridge.

Implants of embryonic hippocampus, placed into a cavity transecting the septo-hippocampal pathway in adult rats, have previously been shown to promote the regeneration of the lesional septo-hippocampal axons across the cavity. The present study provides electrophysiological evidence that these regenerating acetylcholinesterase-containing axons are able to re-establish atropine-sensitive excitatory synaptic connections in the grafted hippocampus as well as in the dorsal part of the initially denervated host hippocampus, thus demonstrating that intracerebral tissue implants can promote true, functional regeneration across a major tissue defect in the adult mammalian CNS.