Publications by authors named "William H Overman"

Performance on the Iowa Gambling Task (IGT) in clinical populations can be interpreted only in relation to established baseline performance in normal populations. As in all comparisons of assessment tools, the normal baseline must reflect performance under conditions in which subjects can function at their best levels. In this review, we show that a number of variables enhance IGT performance in non-clinical participants.

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Males outscore females on the original version of the Iowa Gambling Task (IGT). This may be due to differential regional prefrontal cortical activation by males and females during the task. PET imagery indicates increased activation in dorsolateral (DL) prefrontal cortex (PFC) in males and in medial orbital (ORB) PFC in females.

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Macaques indicated their detection of onset or alteration of 0.2-ms pulses applied in various configurations through electrodes implanted in striate cortex. When microelectrodes were introduced and left in place, the threshold for detection of 100-Hz pulses nearly doubled within 24 h.

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Performance on the Iowa Card Task (ICT) is impaired in several populations that demonstrate poor decision-making and risk-taking including patients with damage to the ventromedial prefrontal cortex. For some individuals, adolescence is a period of poor decision-making and risk-taking. Adolescence is also a period of neuroanatomic and neurochemical remodeling.

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Through the use of several tests of cognition we have documented sex differences in young children, adolescents, and adults on tasks that rely on the integrity of the orbital prefrontal cortex. In children under three years of age, males performed with significantly fewer errors than did females on tests of object reversals. No significant sex differences were found in older children, despite the use of a more challenging object reversal task.

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