The amygdala is thought to process fear-related stimuli rapidly and nonconsciously. We found that an individual with complete bilateral amygdala lesions, who cannot recognize fear from faces, nonetheless showed normal rapid detection and nonconscious processing of those same fearful faces. We conclude that the amygdala is not essential for early stages of fear processing but, instead, modulates recognition and social judgment.Subject SM has complete bilateral lesions of the amygdala and is impaired in her recognition of fear 1 , an impairment that is consistent with previous studies showing activation of the amygdala to overt and masked fear faces 2 . These studies have suggested that the amygdala is involved in pre-attentive, rapid processing, whereby the amygdala receives subcortical visual information via the superior colliculus and pulvinar thalamus 3 . Such a picture is similar to the known subcortical route for the amygdala in auditory fear conditioning, as demonstrated in rats, and is consistent with blood oxygen level-dependent activation of the amygdala by nonconscious fearful faces in humans 4 . However, there are discrepancies with this view of amygdala function. Some neuroimaging studies have found that the amygdala's response to fearful faces is strongly modulated by conscious detectability, at least when backward masking is used 5 . Electrophysiological latencies recorded in the amygdala are, by and large, inconsistent with rapid visual processing 6 and there is no direct anatomical evidence to support the rapid visual subcortical route that has been hypothesized 7 . These discrepancies suggest that the amygdala modulates social judgments of fear, rather than initial pre-attentive detection.To help resolve this debate regarding the amygdala's contribution to fear processing, we tested subject SM on rapid detection of fear-and threat-related stimuli. In our first experiment, subjects saw a target stimulus (fearful face, angry face or scene showing threat) next to neutral stimuli for 40 ms (unmasked) and had to push a button as rapidly as possible to indicate which face showed more fear/anger or which scene was more threatening (Supplementary Fig. 1).Correspondence should be addressed to N.T. (naotsu@gmail.com). 4 Present address: Department of Radiology, University of California San Diego, San Diego, California, USA. 5 These authors contributed equally to this study.Note: Supplementary information is available on the Nature Neuroscience website. SM's performance on this task was completely normal for all three threat-related categories ( Fig. 1a). As reported previously 1 , SM rated the intensity of fear shown in the same face stimuli substantially lower than did the controls (2.8 and 3.7 s.d. below the normal mean on the two testing sessions). Control experiments ruled out several possible interpretations (Supplementary Methods and Supplementary Table 1). First, we used backward masking in the control experiments, as it might be required to prevent afterimages to demonstrate the amygdala's ...