EFFECTS OF KAINIC ACID MICROINFUSIONS ON HIPPOCAMPAL TYPE-2 RSA(THETA)

This study investigated the effects of bilateral, selective lesions of subfield CA3, produced by intrahippocampal administration of kainic a cid, on the generation of hippocampal type 2 RSA. Within 4 weeks of le sioning, animals were anaesthetized with urethane and microelectrode d epth profiles were performed throughout the dorsal-ventral extent of t he hippocampus. In control animals, spontaneous and stimulation-induce d RSA was present at the amplitude maxima in stratum oriens of the CA1 and at the level of the hippocampal fissure. Animals that received in trahippocampal microinfusions of kainic acid showed a significant redu ction of RSA amplitude at both the stratum oriens and fissure regions. These results suggest that the CA3 subfield may play an important rol e in the production of type 2 RSA.