Does Conditioning Contribute to Kindling? 1 Does Inadvertent Conditioning Contribute to the Major Features of Kindling?

Conventional kindling experiments appear ideal for generating inadvertent conditioned effects: A variety of stimuli (e.g., removal from the home cage, attachment to the stimulation lead, and placement in the stimulation environment) are repeatedly presented to the animal prior to each stimulation and convulsion. We recently demonstrated that the stimulation environment can have a major impact on both kindled convulsions and interictal behaviour. Rats received periodic stimulations to the basolateral amygdala (BA) in one conditional environment (CS+) and an equal number of sham stimulations (the stimulation lead was attached but no current was delivered) in a second environment (CS-) in a quasirandom sequence. As kindling progressed, the rats became more defensive in the CS+ environment than in the CSenvironment; and, when they were finally stimulated in the CSenvironment, their convulsions were substantially less severe than in the CS+ environment. Furthermore, the kindled rats preferred the CSenvironment to the CS+ environment in a subsequent conditioned place preference test. Since this demonstration that the stimulation environment can have a significant effect on kindled convulsions and interictal behaviour, our research has focused on four questions. First, are the effects of the stimulation environment on kindled convulsions a product of Pavlovian conditioning? Second, can the kindling of brain structures other than the BA produce conditioned effects; and, if so, are such effects comparable to those of BA kindling? Third, can stimuli other than the stimulation environment function as inadvertent conditional stimuli (CSs) in conventional kindling experiments? And fourth, do inadvertent conditioned effects influence the defining features of kindling (e.g., permanence)? This paper focuses on samples of these four lines of research.