INVESTIGATION OF FACIAL RECOGNITION MEMORY AND HAPPY AND SAD FACIAL EXPRESSION PERCEPTION - AN FMRI STUDY

We investigated facial recognition memory (for previously unfamiliar f aces) and facial expression perception with functional magnetic resona nce imaging (fMRI). Eight healthy, right-handed volunteers participate d. For the facial recognition task, subjects made a decision as to the familiarity of each of 50 faces (25 previously viewed; 25 novel). We detected signal increase in the right middle temporal gyrus and left p refrontal cortex during presentation of familiar faces, and in several brain regions, including bilateral posterior cingulate gyri, bilatera l insulae and right middle occipital cortex during presentation of unf amiliar faces. Standard facial expressions of emotion were used as sti muli in two further tasks of facial expression perception. In the firs t task, subjects were presented with alternating happy and neutral fac es; in the second task, subjects were presented with alternating sad a nd neutral faces. During presentation of happy facial expressions, we detected a signal increase predominantly in the left anterior cingulat e gyrus, bilateral posterior cingulate gyri, medial frontal cortex and right supramarginal gyrus, brain regions previously implicated in vis uospatial and emotion processing tasks. No brain regions showed increa sed signal intensity during presentation of sad facial expressions. Th ese results provide evidence for a distinction between the neural corr elates of facial recognition memory and perception of facial expressio n but, whilst highlighting the role of limbic structures in perception of happy facial expressions, do not allow the mapping of a distinct n eural substrate for perception of sad facial expressions. (C) 1998 Els evier Science Ireland Ltd. All rights reserved.