COMPARISON OF THE SHORT-LASTING AND LONG-LASTING EFFECTS OF PERFORANTPATH KINDLING ON RADIAL MAZE-LEARNING

The present experiment compared the long-lasting with the short-lastin g effects of kindling the perforant path input to the hippocampal form ation on the acquisition of two radial maze tasks. Animals in the long -term group were fully kindled (i.e., Stage 5 motor seizures were evok ed) prior to a stimulation-free training period. Animals in the short- term group were kindled 30-45 min prior to each learning trial. A thir d group of animals served as controls and were never kindled. On both 8-arm and 4/8-arm radial maze tasks, learning impairments were apparen t only in the short-term group. Thus, the impaired learning is more li kely related to the short-term aftereffects of an afterdischarge than to any long-term alterations in the neuronal status of the brain cause d by kindling.