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Response time (RT) variability is a common finding in ADHD research. RT variability may reflect frontal cortex function and may be related to deficits in sustained attention. The existence of a sustained attention deficit in ADHD has been debated, largely because of inconsistent evidence of time-on-task effects. A fixed-sequence Sustained Attention to(More)
Attention-deficit hyperactivity disorder (ADHD) is a heritable childhood onset disorder that is marked by variability at multiple levels including clinical presentation, cognitive profile, and response to stimulant medications. It has been suggested that this variability may reflect etiological differences, particularly, at the level of underlying genetics.(More)
Increased variability in reaction time (RT) has been proposed as a cardinal feature of attention deficit hyperactivity disorder (ADHD). Increased variability during sustained attention tasks may reflect inefficient fronto-striatal and fronto-parietal circuitry; activity within these circuits is modulated by the catecholamines. A disruption to dopamine(More)
IMPORTANCE Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials. OBJECTIVE To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study(More)
This study investigates the food preferences of a single California sea lion, Zalophus californianus. Through operant conditioning the sea lion was taught to associate arbitrary, abstract symbols with different food types. The symbols were then used in paired comparisons to permit the sea lion to indicate and obtain its preferred food. Results indicated a(More)
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