TY  - JOUR
A1  - McLoughlin, Grainne
A1  - Palmer, Jason
A1  - Makeig, Scott
A1  - Bigdely-Shamlo, Nima
A1  - Banaschewski, Tobias
A1  - Laucht, Manfred
A1  - Brandeis, D.
T1  - EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes
JF  - Brain Topography
N2  - Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness.
KW  - EEG
KW  - Genetics
KW  - DRD4
KW  - COMT
KW  - ICA
KW  - Measure projection
Y1  - 2017
U6  - https://doi.org/10.1007/s10548-017-0601-z
SN  - 0896-0267
SN  - 1573-6792
VL  - 31
IS  - 3
SP  - 392
EP  - 406
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Gebel, Arnd
A1  - Lehmann, Tim
A1  - Granacher, Urs
T1  - Balance task difficulty affects postural sway and cortical activity in healthy adolescents
JF  - Experimental brain research
N2  - Electroencephalographic (EEG) research indicates changes in adults' low frequency bands of frontoparietal brain areas executing different balance tasks with increasing postural demands. However, this issue is unsolved for adolescents when performing the same balance task with increasing difficulty. Therefore, we examined the effects of a progressively increasing balance task difficulty on balance performance and brain activity in adolescents. Thirteen healthy adolescents aged 16-17 year performed tests in bipedal upright stance on a balance board with six progressively increasing levels of task difficulty. Postural sway and cortical activity were recorded simultaneously using a pressure sensitive measuring system and EEG. The power spectrum was analyzed for theta (4-7 Hz) and alpha-2 (10-12 Hz) frequency bands in pre-defined frontal, central, and parietal clusters of electrocortical sources. Repeated measures analysis of variance (rmANOVA) showed a significant main effect of task difficulty for postural sway (p < 0.001; d = 6.36). Concomitantly, the power spectrum changed in frontal, bilateral central, and bilateral parietal clusters. RmANOVAs revealed significant main effects of task difficulty for theta band power in the frontal (p < 0.001, d = 1.80) and both central clusters (left: p < 0.001, d = 1.49; right: p < 0.001, d = 1.42) as well as for alpha-2 band power in both parietal clusters (left: p < 0.001, d = 1.39; right: p < 0.001, d = 1.05) and in the central right cluster (p = 0.005, d = 0.92). Increases in theta band power (frontal, central) and decreases in alpha-2 power (central, parietal) with increasing balance task difficulty may reflect increased attentional processes and/or error monitoring as well as increased sensory information processing due to increasing postural demands. In general, our findings are mostly in agreement with studies conducted in adults. Similar to adult studies, our data with adolescents indicated the involvement of frontoparietal brain areas in the regulation of postural control. In addition, we detected that activity of selected brain areas (e.g., bilateral central) changed with increasing postural demands.
KW  - balance
KW  - postural control
KW  - EEG
KW  - Theta
KW  - Alpha-2
KW  - ICA
KW  - youth
Y1  - 2020
U6  - https://doi.org/10.1007/s00221-020-05810-1
SN  - 0014-4819
SN  - 1432-1106
VL  - 238
IS  - 5
SP  - 1323
EP  - 1333
PB  - Springer
CY  - New York
ER  -