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Abstract:
Abstract: A critical function of working memory (WM) is the
ability to suppress irrelevant or no-longer-relevant information.
The goal of this experiment was to investigate the neural basis of
interference resolution within WM through separate manipulations of
WM load and interference in Sternberg's Item Recognition paradigm.
Increased interference might place demands on different brain
regions than increased load, providing support for the idea that
interference resolution is a distinct process operating within WM.
Alternatively, interference and load manipulations might have
similar effects on brain activation, suggesting that an increase in
interference might be functionally equivalent to an increase in
load. We acquired whole-brain fMRI data for 8 healthy young
volunteers (ages 19-32; 4 F, 6 M) while they performed alternating
blocks of 4 different Item Recognition trial types: Load1
(Baseline), Load4 Low Recency (LR), Load4 High Recency (HR), and
Load6. Both the load manipulation and, to a lesser extent, the
interference manipulation resulted in slowing of response times.
However, the interference manipulation was associated with greater
brain activation than the load manipulation in a number of brain
regions including dorsolateral and anterior prefrontal cortices.
These results suggest that interference resolution involves
specific prefrontal circuits that cannot be accounted for simply by
WM task difficulty.
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