Spatial attention in healthy adults is modulated by DNA variation in the dopamine transporter gene (DAT1) and by attentional load

Newman, Daniel (2011). Spatial attention in healthy adults is modulated by DNA variation in the dopamine transporter gene (DAT1) and by attentional load Honours Thesis, School of Psychology, The University of Queensland.

       
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Author Newman, Daniel
Thesis Title Spatial attention in healthy adults is modulated by DNA variation in the dopamine transporter gene (DAT1) and by attentional load
School, Centre or Institute School of Psychology
Institution The University of Queensland
Publication date 2011-10-12
Thesis type Honours Thesis
Supervisor Associate Professor Mark Bellgrove
Total pages 109
Language eng
Subjects 1701 Psychology
Abstract/Summary Examining the interactions between genetic differences and attention mechanisms in healthy participants may provide fundamental knowledge regarding the biological basis of human cognition. Recent behavioural studies suggest that DNA variation in the dopamine transporter gene (DAT1; a risk marker for ADHD) biases visuospatial attention in healthy children and children with ADHD. Visuospatial bias may also be influenced by demands on non-spatial attention resources. No prior studies have examined the influence of non-spatial attention load on visuospatial bias, conditional upon underlying genetics, in a non-clinical sample. This thesis directly addresses this question, guided by the a priori hypothesis that DAT1 genotype influences behavioural and electrophysiological markers of visuospatial bias. Healthy adults were asked to react to sudden onset peripheral targets while demand on non-spatial attention was manipulated via a central task. Participants were genotyped for a DAT1 polymorphism that confers risk for ADHD and were consequently assigned to a low-risk or high-risk genotype group. Peripheral target response times revealed a typical leftward spatial bias, indicative of right hemisphere dominance in spatial attention, for those with the low-risk genotype but not for those with the high-risk genotype. Initial evidence for disrupted right hemisphere visuospatial processing in those with the high-risk genotype was uncovered at an electrophysiological level; however this relationship was abolished by increased demand on non-spatial attention. These data support the argument that DAT1 genotype modulates the right hemisphere attention networks, thus modulating visuospatial bias. The current results contribute to our understanding of the biological basis spatial attention, and to our understanding of genetic risk factors in ADHD.
Keyword Spatial attention
DNA variation in dopomine transport gene
Genetic risk factors in ADHD

 
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Created: Thu, 21 Jun 2012, 15:48:10 EST by Mrs Ann Lee on behalf of School of Psychology