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Abstract:
One problem in developing more specific models of cognition
is that the tasks studied tend to be complex (e.g., the n-back) and
vary in the combinations of component cognitive processes that they
recruit depending on aspects of the task, e.g., load or delay. We
investigated one of the most elementary, but critical, components
of reflection--refreshing a just-active representation (Johnson,
1992). While reading words, participants were cued to think of the
just previous word (refresh), saw the previous item again (repeat),
or read a new item (read). In both blocked and event-related fMRI
studies, similar areas of left prefrontal cortex (PFC) and left
parietal cortex showed greater activation in the refresh condition.
A third control study showed that this activation could not be
attributed to task switching, holding a task agenda, or attending
to the cue to refresh. On a subsequent old/new recognition test,
the d' scores were in the direction expected
(refresh>repeat>read) based on other behavioral studies of
the refresh operation. These data will be discussed in relation to
other findings implicating left PFC in memory retrieval/evaluation
(Raye, Johnson, Mitchell, Nolde & D'Esposito, 2000).
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