The ''M2'' electromyographic response to random perturbations of arm movements is missing in long-trained monkeys

Post-trial injections of norepinephrine, but not dopamine, into the amygdala produce a long-term retention deficit (amnesia) for a 1-trial footshock experience in rats. In contrast, post-trial injections of dopamine, but not norepinephrine, into the caudate produce long-term facilitation. The data provide evidence for brain region-neurotransmitter specificity which supports a multiple component hypothesis.