Memory strength effects in fMRI studies: A matter of confidence
de Zubicaray, G. I., McMahon, K. L., Dennis, S., & Dunn, J. C. (2011) Memory strength effects in fMRI studies: A matter of confidence. Journal of Cognitive Neuroscience, 23(9), pp. 2324-2335.
To investigate potentially dissociable recognition memory responses in the hippocampus and perirhinal cortex, fMRI studies have often used confidence ratings as an index of memory strength. Confidence ratings, although correlated with memory strength, also reflect sources of variability, including task-irrelevant item effects and differences both within and across individuals in terms of applying decision criteria to separate weak from strong memories. We presented words one, two, or four times at study in each of two different conditions, focused and divided attention, and then conducted separate fMRI analyses of correct old responses on the basis of subjective confidence ratings or estimates from single- versus dual-process recognition memory models. Overall, the effect of focussing attention on spaced repetitions at study manifested as enhanced recognition memory performance. Confidence- versus model-based analyses revealed disparate patterns of hippocampal and perirhinal cortex activity at both study and test and both within and across hemispheres. The failure to observe equivalent patterns of activity indicates that fMRI signals associated with subjective confidence ratings reflect additional sources of variability. The results are consistent with predictions of single-process models of recognition memory.
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|Item Type:||Journal Article|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2011 Massachusetts Institute of Technology|
|Deposited On:||02 Oct 2015 06:21|
|Last Modified:||16 Oct 2015 02:33|
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