Effect of brain-stem lesions on retention of a conditioned reflex in cats

The effects of central brain-stem lesions on memory was studied in eight animals with previously acquired avoidance motor conditioned reflexes. The prelesion training included conditioning to flashes or clicks, differentiation and transfer. After extensive bilateral, two-stage electrolytic lesions of the central mesencephalon and after subsequent recovery for 5–12 weeks, the animals were subjected to reconditioning, redifferentiation and retransfer. The lesions did not produce loss of the previously established conditioned response. The memory of training prior to the lesion was perfect and comparable to that in normal cats with equal intervals in the training.