Brain Metabolic Dysfunction in Capgras Delusion During Alzheimer's Disease: A Positron Emission Tomography Study.

Capgras delusion is characterized by the misidentification of people and by the delusional belief that the misidentified persons have been replaced by impostors, generally perceived as persecutors. Since little is known regarding the neural correlates of Capgras syndrome, the cerebral metabolic pattern of a patient with probable Alzheimer's disease (AD) and Capgras syndrome was compared with those of 24-healthy elderly participants and 26 patients with AD without delusional syndrome. Comparing the healthy group with the AD group, the patient with AD had significant hypometabolism in frontal and posterior midline structures.

Gaze direction influences awareness in recognition memory for faces after intentional learning.

Previous research has shown that direct gaze elicits more hits than deviated gaze in face recognition tasks. The aim of the present study was to evaluate whether the state of awareness that accompanied recognition was different for faces with eye gaze directed toward the observer as compared with faces looking elsewhere. This state of awareness was assessed using the "Remember-Know-Guess" paradigm.

Perceptual memory for highly familiar people's body shape: manipulation of images of the self and friend.

Previous studies have shown that people's ability to detect, from memory, alterations in highly familiar faces is excellent. Indeed, just noticeable differences for the detection of small alterations in a recognition-memory task were not significantly different from the corresponding measures in a perceptual-discrimination task (Brédart and Devue, 2006 Perception 35 101-106; Ge et al, 2003 Perception 32 601-614). The object of the present study was to evaluate whether people's perceptual memory for body shapes of very familiar persons reaches the high level of precision that was reported for face memory.