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Abstract:
Previous neuroimaging studies have shown that regions of the
posterior parietal cortex (PPC) respond more vigorously during
mental rotation than during non-rotated control conditions. Studies
have also demonstrated quantitative relationships between activity
in these regions and several behavioral performance measures. Are
these same regions of the PPC more strongly activated during
rotated object recognition? Also, is there a similar relationship
between activity in PPC and behavior during rotated object
recognition? We investigated these questions using fMRI at 1.5T.
Subjects performed an object naming task using pictures of everyday
common objects and two classic mental rotation tasks involving
left/right and mirror-reversal discriminations. Stimulus
orientation was varied systematically in each task and results were
analyzed using a modified general linear model for serially
correlated data. Results of Experiment #1 indicate that regions of
the PPC known to be involved in mental rotation, as well as regions
of the inferior temporal cortex, show greater activity during
rotated object recognition relative to a non-rotated recognition
control condition. Further experiments are in progress to test
whether there is a similar quantitative relationship between brain
activity and behavior in these two tasks. Results will be discussed
with respect to theories of object recognition, and the role of
mental rotation during rotated object recognition.
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