Long-term deficits in passive avoidance responding following experimental febrile convulsions during infancy.

Human infantile febrile convulsions are occasionally associated with later deficits in cognitive and motor performance. In the present report, experimental febrile convulsions during various stages of infancy in the rat were investigated. Infant rats that were subjected to a single hyperthermia-induced convulsion at 10, 15, or 20, but not 5, days of age required more trials than controls to acquire a step-down passive avoidance response when tested as adults (50-60 days of age). Although rats that were subjected to a series of convulsions during infancy also evinced deficits in passive avoidance responding at adulthood, the magnitude of the effect was not appreciably greater than that following a single convulsion. The present results indicate that a single experimental febrile convulsion during infancy can have long-term effects on subsequent behavior.