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Abstract:
Abstract: To examine the pattern of brain activation during
the performance of a Gambling task (Bechara et al., 1994), we
measured regional cerebral blood flow (rCBF) using positron
emission tomography with H215O. The Gambling task is a test of
decision-making using a mixed contingency paradigm involving a
balance between reward and penalty. Substance abusers and patients
with orbitofrontal lesions show performance deficits on this task.
Brain regions likely to be involved in this task are the medial
temporal, dorsolateral prefrontal and orbitofrontal cortices. The
PET paradigm included 2 resting, 2 neutral task and 2 active task
conditions. Data were analyzed using SPM96. Subjects were 6 healthy
controls (mean age = 33.4 ± 8.6 years). Mean performance on
the task (number of cards picked from the advantageous decks minus
the number of cards picked from the disadvantageous decks) was 7
± 34 cards. Brain regions activated by the task
(p<0.01) included left orbitofrontal cortex (BA 47), left
insula, left and right prefrontal cortex (BA 6, 9, 44), and right
cerebellum. Performance on this task seems to activate the regions
that may be altered in addiction. Ongoing studies will increase the
sample size and focus on the comparison of substance abusers with
healthy controls.
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