An Examination Of The Persistence Of Kindling, A Model For Neural Plasticity

The primary purpose of the experiments discussed here was to discover whether kindling is a permanent and stable state or a slowly eroding persistent state. In addition, questions concerning the relationship between retention and seizure generalization, site of stimulation, and stimulus characteristics were addressed. Experiment One results showed that a large part of the kindling effect was retained over the interval, but there was also a consistent degree of fallback seen when comparing the kindling manifestations just before the interval with those exhibited on the first rekindling session. The retention of the kindling effect was not dependent on the animal attaining a fully generalized convulsion, but the question of whether kindling is a steady state or a slowly eroding state was not answered. Experiment Two examined retention of a fully generalized convulsion in animals tested at intervals ranging from one week to twenty-four weeks. On the basis of the evidence, it was suggested that the term \u27persistence\u27 more clearly described the retention of the kindling effect. Experiment Three addressed the relationship between persistence and site of stimulation by comparing the retention of the kindling effect in animals kindled in the amygdala with animals kindled in the ventral hippocampus. The AD measures showed that the hippocampal group had either similar fallback or, in the case of duration, slightly more robust retention. Experiment Four examined the question of whether the parameters of the stimulus used to kindle the animal were important. One group received low frequency (3 Hz) stimulations to produce a fully generalized convulsion, and a second group was kindled using a 60 Hz stimulus that was supra-threshold. As expected, the low frequency group took significantly fewer ADs to reach their first fully generalized convulsion and the conventionally kindled and suprathreshold kindled animals required a similar number of ADs. It was concluded that the degree of persistence after the 12 week interval was not different despite the differences in the parameters of the stimuli. Together Experiment Three and Four support the idea that kindling persistence is not tied to a particular stimulus, but rather is a result of a particular type of activation of the nervous system, namely AD coupled with its behavioral expression as a convulsion. (Abstract shortened by UMI.