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Abstract:
The Raven's Progressive Matrices (RPM, Raven, 1962) is a
nonverbal measure of fluid intelligence and reasoning and is
sensitive to frontal lobe disfunction. The matrices involve varying
levels of relational structure, which may underlie RPM's dependence
on frontal lobe function. To determine the neural components
underlying the mediation of relational structure, we had subjects
complete problems fashioned after the Raven's matrices, presented
in blocks of varying levels of relational complexity. Additionally,
we had subjects perform blocks in which relational complexity
remained constant and increasing numbers of distracters were
included. Sixteen echoplanar slices 4mm thick were obtained
obliquely (TR = 3sec, TE = 45msec, flip angle = 80 degrees).
Parametric analysis of increasing relational complexity and
difficulty revealed that dorso-lateral prefrontal cortex responded
as subjects solved relational problems, and as relational
complexity increased, more anterior DLPFC was recruited. Increasing
difficulty in the distracter problems did not produce a similar
progressively anterior involvement. We conclude that complex
cognition involving relationally complex information recruits first
DLPFC, then anterior PFC, as complexity increases. Keyword: Problem
solving, Numerical processing
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