Conditioning of ictal and interictal behaviors in rats by amygdala kindling: Context as the conditional stimulus

The authors showed that conditional effects of the stimulation environment modulate both the ictal and interictal behaviors of rats subjected to amygd ala kindling. Rats received 53 stimulations to the left basolateral amygdal a in 1 conditional stimulus (CS) context (CS+) and 53 sham stimulations (th e stimulation lead was attached but no current was delivered) in another co ntext (CS-), quasirandomly over 54 days. Three kinds of conditional effects were observed. First, after several stimulations, less ambulatory activity , more freezing, and less rearing reliably occurred in the CS+ context than in the CS context. Second, after 45 stimulations, all of the rats chose th e CS- context over the CS+ context in a conditioned place preference test. Third, when the rats were finally stimulated in the CS- context, their moto r seizures were less severe: Latencies were longer, motor seizures were sho rter, convulsive patterns were of a lower class, and there were fewer falls .