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Abstract:
Abstract: The Tower-of-London (TOL) task has been widely used
to evaluate the integrity of executive functions, which are
normally associated with the prefrontal cortex. This study used
functional magnetic resonance imaging (fMRI) to identify the
regions the mediate the executive functions required by the TOL
task. The results indicated that two measures of fMRI-measured
activation volume (the number of activated voxels and percent
change in signal intensity) were modulated by problem difficulty,
or the number of sub-goals necessary to solve given problems. This
suggests that the executive components of the TOL task are mediated
by a large-scale network of cortical regions, which includes
bilateral dorsolateral prefrontal and parietal cortices, and the
left inferior frontal gyrus. The observed relationships between
problem difficulty and activation volume within each of these
cortical regions were used to guide the development of 4CAPS, a
production system architecture that has previously been used to
model high-level cognitive tasks (e.g., language comprehension). In
the TOL task, 4CAPS accounts for how task demands (e.g., problem
difficulty) engenders behavioral performance (error rates and
response latencies) and specific patterns of cortical activation
(activation volume and response profiles of individual voxels
within activated cortical regions). The architecture thus provides
a comprehensive framework for understanding the relationship
between cognition and its neural implementation in a complex task
domain.
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