Unformatted text preview:

The Role of VMPC in Metamemorial Judgmentsof Content RetrievabilityDavid M. Schnyer1,2, Lindsay Nicholls1, and Mieke Verfaellie1Abstract& Making judgments about the retrievability of information isa critical part of the metamemory processes engaged duringremembering. A recent study of patients with frontal lesionssuggests that ventral medial prefrontal cortex (VMPC) plays acritical role in such judgments [Schnyer, D. M., Verfaellie, M.,Alexander, M. P., Lafleche, G., Nicholls, L., & Kaszniak, A. W. Arole for right medial prefrontal cortex in accurate feeling ofknowing judgments: Evidence from patients with lesions tofrontal cortex. Neuropsychologia, 42, 957–966, 2004]. Theobserved impairment was thought to reflect an inability todetermine the accessibility of memory contents. To furtherexamine the neuroanatomical basis of content accessibilityassessment, we used fMRI in an episodic feeling-of-knowing(FOK) paradigm. Participants were asked to make trial-by-trialpredictions about the retrievability of the final word thatcompleted studied sentences and then to select the correctcompletion from among alternatives. Results indicated that theVMPC is engaged during accurate FOK judgments and itsactivation is modulated by retrieval rating. Structural equationsmodeling supported the notion that VMPC, as part of a broaderleft hemisphere network involved in memo ry retrieval,monitors the output of the retrieval process. More generally,VMPC may participate in metacognitive processes that allow forthe comparison of available data against an internal model. &INTRODUCTIONThe attempt to retrieve information from memory is notalways immediately successful. Faced with failure, a per-son must determine the extent to which informationseems readily accessible and, therefore, whether thereis sufficient reason to continue to try and retrieve it(Koriat, 2000). The cognitive mechanisms by whichsuch metamemory judgments are made have been thefocus of extensive study using the feeling-of-knowing(FOK) paradigm (Koriat, 1993; Metcalfe, 1993; Reder &Ritter, 1992).Two theoretical views have dominated this area ofresearch. One view has argued that FOK judgments aremade primarily on the basis of the relative familiarity ofthe recall cue (Metcalfe, 1993; Reder & Ritter, 1992), andreflect a rapid assessment prior to engaging in a retrievalattempt. A second view has suggested that these judg-ments are made by engaging the retrieval process andmaking assessments of the perceived accessibility o fmemory contents (Koriat, 1993). Illustrating the role offamiliarity, Reder (1987) found that increasing the famil-iarity of retrieval cues through priming resulted in high-er FOK ratings, with no effect on actual retrieval.Illustrat ing the role of content accessibility, Koriat(1993) found a positive relationship between theamount of fragment information retrieved by a partici-pant and ratings of future retrievability. This relationshipwas found irrespective of accuracy. Although famil-iarity and accessibility views have o ften been pittedagainst each other (Miner & Reder, 1994), there re-cently has been an attempt to integrate the two (Koriat& Levy-Sadot, 2001). Koriat and Levy-Sadot (2001) haveproposed that retrieval predictions entail a cascadingtwo-step process involving both assessments of cue-familiarity and evaluation of the accessibility of memorycontents. By this view, items are initially assess ed forfamiliarity and then either discounted (feeling-of-not-knowing) or slated for further search. Assessment ofcontent availability consists of implementing the searchor retrieval process and mon itoring the results. Al-though that process m ay not alw ays be suc cessful,it can produce fragments of information that are thenevaluated in order to come to a judgment about anitem’s availability in memory (Koriat, 2000).Although considerable knowledge has been gainedabout the cognitive processes that contribute to meta-memory judgme nts, much less is k nown about thefunctional neuroanatomy of these decisions. Researchhas suggested that frontal cortical structures are criticallyinvolved in predictions about memory retrieval in theFOK paradigm (Souchay, Isingrini, & Espagnet, 2000;Janowsky, Shimamura, & Squire, 1989; Shimamura &Squire, 1986), but there has as yet been little attempt toelucidate the role of specific frontal regions (or otherregions) in the assessment of either cue-familiarity or1Memory Disorders Research Center, Boston UniversitySchool of Medicine, and the Boston VA Healthcare Center,2MGH/MIT/HMS Athinoula A. Martinos CenterD 2005 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 17:5, pp. 832–846accessibility of memory contents—the tw o processesthat are thought to mediate these judgments.In a recent FOK study in patients with damage to thefrontal cortex (Schnyer et a l., 2004), we found thatpatients whose lesion encompassed the right ventralmedial prefrontal cortex (VMPC ) were impaired inmaking predictions about their subsequent recognitionperformance. Because familiarity-based assessment wasdemonstrated to be intact in these patients, we con-cluded that the primary contribution of this region tometamemory judgments was in the assessment of theaccessibility of memory contents. This conclusion is inline with a recent proposal by Moscovitch and Winocur(2002) that the VMPC and the anterior prefrontal cortexplay an important role in the intuitive evaluation ofactual stored memory contents.The findings in patients with damage to the prefrontalcortex leave unanswered several important questionsabout both the neuroanatomical underpinnings of meta-memory judgments and the functional role of the VMPCin these judgments. First, lesion studies cannot delineatewhether the effect of a lesion is due to damage in localgray matter or to pathways that connect distributed non-affected regions (Price, Warburton, Moore, Frackowiak,& Friston, 2001). This connectivity issue is especiallyimportant in determining the role of the VMPC, as thisregion contains many of the major pathways connectingthe frontal cortex with the limbic and temporal regions.Second, although lesion studies are esse ntial forpinpointing regions that are critically involved in taskperformance, they fail to identify additional regions thatmay also contribute to performance, and they providelittle evidence as to how these regions interact (Price,Mummery, Moore, Frackowiak, & Friston, 1999). TheVMPC may be involved in evaluating the


View Full Document

UT PSY 394U - Elements of Culture

Documents in this Course
Roadmap

Roadmap

6 pages

Load more
Download Elements of Culture
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Elements of Culture and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Elements of Culture 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?