Remembering familiar people: The posterior cingulate cortex and autobiographical memory retrieval

Most functional imaging studies of memory retrieval investigate memory for standardized laboratory stimuli. However, naturally acquired autobiographic al memories differ From memories of standardized stimuli in important ways. Neuroimaging studies of natural memories may reveal distinctive patterns o f brain activation and may have particular value in assessing clinical diso rders of memory. This study used functional magnetic resonance imaging to i nvestigate brain activation during successful retrieval of autobiographical memories elicited by name-cued recall of family members and friends. The c audal part of the left posterior cingulate cortex was the most strongly act ivated region and was significantly activated in all eight subjects studied . Most subjects also showed significant activation of the left anterior orb itomedial, anterior middle Frontal. precuneus, cuneus. and posterior inferi or parietal cortices. and the right posterior cingulate and motor cortices. Our findings are consistent with prior studies showing posterior cingulate cortex activation during autobiographical memory retrieval. This region is also consistently activated during retrieval of standardized memory stimuli when experimental designs emphasizing successful retrieval are employed. O ur results support the hypothesis that the posterior cingulate cortex plays an important role in successful memory retrieval. The posterior cingulate cortex has strong reciprocal connections with entorhinal and parahippocampa l cortices. Studies of early Alzheimer's disease. temporal lobectomy, and h ypoxic amnesia show that hypometabolism of the posterior cingulate cortex i s an early and prominent indicator of pathology in these patients. Our find ings suggest that autobiographical memory retrieval tasks could be used to probe the functional status of the posterior cingulate cortex in patients w ith early Alzheimers disease or at risk for that condition. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.