The blink reflex of acoustic startle reflex (ASR) is modulated by emotions and a loss of physiological aversive ASR potentiation is reported in humans following amygdala lesions. Patients with narcolepsy-cataplexy (NC) were found to have normal ASR, but they failed to exhibit startle potentiation during unpleasant stimuli. This absence of aversive ASR potentiation gives support to the hypothesis of an amygdala dysfunction in human NC.