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Abstract:
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Encoding of salient information is believed to be a key attentional process that facilitates learning by devoting cognitive resources to the most relevant sensory information. This study examined the relationship between a variation of the dopamine transporter (DAT) gene, which modulates dopamine transporter expression in the striatum, and performance on two measures of salience, the Salience Attribution Task (SAT) and Learned Irrelevance (LIrr) task. The SAT measures implicit and explicit learning of information made salient by monetary rewards, whereas the LIrr task measures the learning of information made salient by stimulus-response associations. Subjects were either homozygous (10/10) or heterozygous (9/10) for the 10-repeat allele of the DAT genotype. On the SAT, implicit adaptive salience was numerically higher in 9/10 carriers relative to 10/10 carriers, although this result did not achieve statistical significance. Aberrant salience did not differ by genotype. On the LIrr task, both groups exhibited similar amounts of learned irrelevance. These genotypic differences in performance on reward-based behavior but concomitant similarities in stimulus-response association learning indicate that individual differences in DAT activity had differential effects on encoding of salient information selective to motivational function. |