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Abstract:
Abstract: Fragile X Syndrome (fraX) is the most common
inherited cause of neurodevelopmental disability, with a prevalence
rate estimated at 1 per 2-5000 live births. Attentional deficits
have been widely reported in fraX. Previous studies have shown that
subjects with attention deficit hyperactivity disorder (without
fraX) have decreased brain activation in frontal and striatal
regions. We used fMRI to investigate brain activation during an
attentional task in 12 fraX girls (ages 10 - 22, mean IQ = 80) and
13 age and gender- matched controls (ages 11-22, mean IQ = 120).
Although fraX subjects had significantly lower IQ scores
(p<.0001), their performance during a Go-NOGO task was
equivalent to that of the control group. Overall, the control group
showed more activation in the left and right anterior cingulate,
striatum, and left and right inferior frontal gyri, however, the
differences were not statistically significant. We found a
significant association between increased anterior cingulate gyrus
activation and task performance in both groups. Our findings
suggest that fraX females, despite lower IQ, are not impaired on
the Go-NOGO task and show similar activation profiles compared to
typically developing controls. Further, no relationship was found
between IQ and performance or brain activation. Future studies will
investigate whether subjects with lower IQ (< 80) show
significant deficits in performance and activation.
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