Cerebral Cortex Advance Access originally published online on April 28, 2006
Cerebral Cortex 2006 16(8):1126-1133; doi:10.1093/cercor/bhj054
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Neural Processes Underlying Memory Attribution on a Reality-monitoring Task
Department of Psychology, Harvard University, Cambridge, MA 02138 and the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA
Address correspondence to Elizabeth A. Kensinger, 33 Kirkland Street, Cambridge, MA 02138, USA. Email: ekensing{at}wjh.harvard.edu.
A relatively common form of memory distortion arises when individuals must discriminate items they have seen from those they have imagined (reality monitoring). The present fMRI investigation (at 1.5 T) focused on the processes that relate to memory assignment regardless of accuracy (e.g. that correspond with the belief that an item was presented as a picture, regardless of whether that belief is correct). Prior to the scan, participants (n = 16) viewed concrete nouns and formed mental images of the object named. Half of the names were followed by the object's photo. During the scan, participants saw the object names and indicated whether the corresponding photo had been studied. Activity in visual-processing regions (including the precuneus and fusiform gyrus) corresponded with the attribution of an item to a pictorial presentation. In contrast, activity in regions thought to be important for self-referential processing (including the ventromedial prefrontal cortex and posterior cingulate gyrus) was associated with attribution to a nonpresented source. These neural findings converge with behavioral evidence indicating that individuals use the amount of different types of information retrieved (e.g. perceptual detail, information about cognitive operations) to determine whether an item was imagined or perceived.
Key Words: fMRI • memory distortion • self-referential processing • visual processing