Dorsal hippocampal kindling selectively impairs spatial learning/short-term memory

Kindling with electrical stimulation of the dorsal hippocampus has been sho wn to disrupt spatial task performance in rats. The present study investiga ted the specificity of this effect in terms of the possible contribution of nonmnemonic effects, the presence of a more general mnemonic deficit, and the involvement of learning/short-term memory and/or long-term memory proce sses. Rats were fully kindled with stimulation of the dorsal hippocampus an d subsequently tested for acquisition, 7-day retention, and 28-day retentio n of a hidden platform (HP) location in the Morris water maze and an object discrimination problem in a modified water maze. To control for nonmnemoni c behavioral impairments, testing on both tasks was preceded by training on visible platform control tasks. Kindling impaired acquisition of the HP lo cation but spared performance on all other aspects of testing, indicating a specific impairment of spatial learning/short-term memory. These results s uggest that epileptogenesis induced by hippocampal stimulation is indeed as sociated with a selective disruption of the mechanisms mediating spatial le arning/short-term memory. Hippocampus 2001;11:275-286. (C) 2001 Wiley-Liss, Inc.