Abstract
Fifteen years ago, Adolphs and his collaborators described a rare patient (SM) with bilateral damage restricted to the amygdala who was unable to recognize fearful faces. Her impairment has recently been attributed to her inability to spontaneously make use of high spatial frequency information from the eye region known to be crucial for fear recognition (Adolphs et al., 2005). This findings support the view that the amygdala's role in fear perception may be much broader than originally believed (i.e., saliency and unpredictability; Adolphs, 2008). We now report the case of a brain-damaged patient, IR, a 52-year-old woman who suffers from large bilateral lesions including the insula and the superior temporal gyrus (STG) but excluding the amygdala. Despite a normal IQ and relatively intact face recognition skills, she is more impaired at recognizing fearful expressions than SM. In order to understand the nature of her selective deficit with fearful faces, IR was instructed to rate the intensity of static and dynamic basic facial expressions on multiple continuous scales. She accurately recognized all expressions except fear (normal hit rates), which she systematically confused with all other expressions. Second, we tracked her gaze while she categorized static basic facial expressions—her gaze maps were relatively normal. Third, we used Bubbles to examine what information she uses to classify fearful and happy expressions. While IR required more information to identify the expressions than controls, she did not differ from them in her use of visual information. Together, these results suggest that IR has a decisional bias against fear. While the amygdala seems to be necessary to appropriately process fearful faces, it does not appear to be sufficient to do so; instead, the case of IR indicates that cortical regions such as the right anterior insula and STG contribute to the recognition of fearful faces.