Conditioning of interictal behaviours, but not ictal behaviours, seizures or afterdischarge threshold, by kindling of the amygdala in rats

Abstract

Rats received 45 pairings of kindling or sham stimulation in distinctive contexts before a conditioned place preference/aversion test, to determine whether the stimulation and seizures were rewarding or punishing. After more pairings, rats received kindling stimulation in each context (switch test). Ictal measures in this test included afterdischarge duration, clonus duration, latency to clonus, class of convulsion and falls. After more pairings, afterdischarge threshold was measured in each context. On every fourth day of pairings, the rats' behaviour in the prestimulation interval was recorded, to measure conditioned anticipatory defensive behaviour. We partially replicated the finding of Barnes et al. (2001, Behav. Neurosci., 115, 1065-1072) that conditioned anticipatory responses and conditioned place aversion are associated with the kindling environment. However, there were no conditioned effects on any ictal measures, including afterdischarge threshold. Our results fail to support the hypothesis that conditioning is a universal mechanism for kindling.