Daily electrical stimulation of the amygdala in cats resulted in the progressive development of seizures through six distinct and sequential stages, culminating in a generalized convulsive seizure within an average of 25.5 days. On completion of the kindling, the generalized seizure-triggering threshold was within 100 to 300 μa, showing an all-or-none property. Electrographically, such seizure development was characterized by early distant propagation, amplitude growth of after-discharge, and development of interictal discharge along the ex-trapyramidal pathways through three distinct steps in which the mid-brain reticular formation plays a vital role in producing widespread secondary alteration and reorganization of brain function.