The case for hemispheric lateralization of the human amygdala in fear processing

The amygdala has increasingly been proposed as a therapeutic target for patients with post-traumatic stress disorder (PTSD). However, the distinct contributions of the left and right amygdala to various aspects of fear processing remain inadequately understood. Here, we critically re-evaluate key findings from human functional neuroimaging and lesion studies on fear conditioning and extinction. We propose that while both amygdalae likely make critical contributions to fear processing, the right is more associated with sensory-mediated fear expression, and the left is associated with cognitive-mediated fear acquisition and extinction. With accumulating evidence from human lesion studies, we suggest that differentially targeting the right versus left amygdala for ablative or neuromodulatory therapies can be crucial for optimizing PTSD treatment.