Poster B48, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Prefrontal dopamine metabolism predicts neurostimulation-linked working memory training gains
Kevin Jones1,2, Jaclyn Stephens1,3, Marian Berryhill1; 1University of Nevada, Reno, 2Georgetown University Medical Center, 3Kennedy Krieger Institute
There is growing awareness that individual differences predict opposing effects on cognitive performances paired with transcranial direct current stimulation (tDCS). One possible explanation is that the effects of tDCS likely depend on individual variations in WM-relevant genetic polymorphisms, such as Catechol-O-methyltransferase (COMT val158met), Dopamine Transporter (DAT), and Brain-Derived Neurotrophic Factor (BDNF val66met). This is particularly relevant as some polymorphisms have a greater impact on cognition in older adults, a population particularly motivated to maintain WM. One hundred and thirty-seven healthy older adults provided saliva samples for genotyping and received longitudinal anodal frontoparietal tDCS (sham, 1 mA, 1.5 mA, or 2 mA) paired with 10 sessions of Visual and Spatial WM training. At baseline, significant group differences in WM performance were predicted by COMT genotype (p = .002). One month after training, there was a significant interaction of COMT genotype, tDCS intensity and WM task (p = .037). Specifically, the COMT val/val adults who received 1.5 mA, showed greater improvement on the Visual WM task, where they were initially weaker, than on the Spatial WM task, where they were initially stronger. Conversely, the COMT met/met adults in the 1.5 mA tDCS group showed the reverse pattern. Neither DAT nor BDNF were predictive of tDCS-linked WM benefits. These data suggest that intrinsic frontal dopamine activity predicts the nature of WM improvement after longitudinal tDCS. Variations in the COMT polymorphism predicted baseline WM performance and interacted with tDCS specific to WM task demands.
Topic Area: EXECUTIVE PROCESSES: Working memory