Disruption of latent inhibition by placement of an electrode in the dorsal hippocampus

Abstract

Rats were implanted unilaterally with electrodes placed in either the dorsal hippocampus or the mesencephalic reticular formation. Subgroups were given either zero or six preexposure trials to a tone that was subsequently paired with a footshock. An additional group of dorsal hippocampal animals was given 12 preexposure trials. Test performance indicated that all groups given preexposure trials, with the exception of the dorsal hippocampal group given six such trials, showed latent inhibition. A second experiment suggested that the disruption of latent inhibition in the dorsal hippocampal animals given six preexposure trials was not due to seizure activity. The implications of these results are discussed.