The "Emotional Numbing" (EN) constitutes one of the core symptoms in PTSD although its exact nature remains elusive. This disorder shows an abnormal response of cortical and limbic regions which are normally involved in understanding emotions since the very earliest stages of the development of processing ability. The aim of our study, which included ten physically healthy subjects with PTSD, diagnosed according to DSM-IV-TR, who survived L'Aquila earthquake of April 6, 2009, and 10 healthy controls matching for age, sex and education, was to examine automatic perceptual sensitivity to facial affect in PTSD, through an affective priming task that was administered during functional magnetic resonance (fMRI). Behavioural data revealed in the PTSD group a higher sensitivity to negative facial affect on an automatic processing level. FMRI data analysis revealed that PTSD subjects showed a significantly higher activation in right insula and left amygdala that we did not observe in healthy subjects; on the contrary, healthy controls showed a greater activation of left lingual gyrus. Our data support the hypothesis that PTSD appears to be sensitive to negative affect on an automatic processing level and correlates with the activation of specific areas involved in processing emotions. An elevated activation of these areas may underlie the emotion dysregulation in PTSD and could explain the Emotional Numbing symptom associated with this disorder. The present study suffers of a number of limitations, for instance, the relatively small sample size did not allow the application of alternative statistical models.