The reduction in long-term spatial memory induced by peripubertal GnRHa-treatment persisted in rams into adulthood even after GnRHa-treatment was discontinued. Development of this cognitive function is, therefore, likely to occur during a critical window of development, which may reflect a time-limited period of hippocampal plasticity. Perturbations in GnRH signaling during this peripubertal period may also have long lasting effects on other brain areas and/or aspects of cognitive function.