Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .
Cellular and subcellular localization of the dopamine transporter in rat cortex.
Publisher Summary Ultrastructural subcellular studies indicate that most of the dopamine transporter ( DAT ) protein in striatal dopamine axons is distributed at the periphery of synapses and at nonsynaptic membrane sites . The extensive distribution of the DAT protein is likely to greatly restrict the extracellular diffusion of dopamine in this brain region . Several neurochemical observations suggest that extracellular dopamine in the prelimbic division , or prefrontal cortex ( PFC ) , undergoes less regulation by DAT-mediated uptake , compared with the striatum . Relative to total tissue content , extracellular dopamine levels are 20 times higher in the PFC than in the striatum . The electron microscopic results from six rats with the best morphology and most robust staining with the rat antibody were quantified in the experiment demonstrated in this chapter . One to two tissue sections per region per animal were examined , and the surface of the tissue was sample d at r and om until at least 40 DAT-immunoreactive processes were photographed . Processes were then numbered on the micrographs from upper left to lower right , and a r and om number generator was used to select 30 processes per region per animal . The processes were then traced using an image analysis system , which calculated their maximum diameter along the short axis . By electron microscopic examination of the dorsolateral striatum , peroxidase immunoreactivity for DAT was abundantly expressed in axon varicosities , some of which made punctate symmetric synapses on spines or distal dendrites
Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .