Investigations of two cases of the Capgras delusion found that both patients showed face-processing impairments encompassing identification of familiar faces, recognition of emotional facial expressions, and matching of unfamiliar faces. In neither case was there any impairment of recognition memory for words. These findings are consistent with the idea that the basis of the Capgras delusion lies in damage to neuro-anatomical pathways responsible for appropriate emotional reactions to familiar visual stimuli. The delusion would then represent the patient's attempt to make sense of the fact that these visual stimuli no longer have appropriate affective significance.
Testing the connections within face processing circuitry in Capgras delusion with diffusion imaging tractography