Superior colliculus lesions impair threat responsiveness in infant capuchin monkeys

► The amygdala does not seem to be necessary for early stages of threat detection. ► Superior colliculi of infant capuchins were lesioned with ibotenic acid. ► Subjects were tested in a food-retrieval test with aversive stimulus. ► Lesioned monkeys showed no inhibition in the presence of snake-toy. ► Data indicate that superior colliculus is important to threat responsiveness.