The impact of the COMT genotype and cognitive demands on facets of intra-subject variability

Salunkhe, G., Feige, B., Saville, C.W.N., Lancaster, T.M. ORCID: https://orcid.org/0000-0003-1322-2449, Stefanou, M.E., Bender, S., Berger, A., Smyrnis, N., Biscaldi, M., Linden, D.E.J. and Klein, C. 2019. The impact of the COMT genotype and cognitive demands on facets of intra-subject variability. Brain and Cognition 132 , pp. 72-79. 10.1016/j.bandc.2019.03.002

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Abstract

Intra-Subject Variability (ISV), a potential index of catecholaminergic regulation, is elevated in several disorders linked with altered dopamine function. ISV has typically been defined as reaction time standard deviation. However, the ex-Gaussian and spectral measures capture different aspects and may delineate different underlying sources of ISV; thus reflecting different facets of the construct. We examined the impact of factors associated with dopamine metabolism, namely, Catechol-O-Methyltransferase Val158Met (COMT) genotype and Working Memory (WM) and response-switching on ISV facets in young healthy adults. The Met allele was associated with overall increased variability. The rather exclusive sensitivity of ex-Gaussian tau to frequencies below 0.025 Hz and the quasi-periodic structure of particularly slow responses support the interpretation of tau as low frequency fluctuations of neuronal networks. Sigma, by contrast, may reflect neural noise. Regarding cognitive demands, a WM load-related increase in variability was present for all genotypes and all ISV facets. Contrastingly, ISV facets reacted differently to variations in response-switching as, across genotypes, sigma was elevated for rare target trials whereas tau was elevated for frequent standard trials, particularly for Met homozygotes. Our findings support the significant role of COMT in regulating behavioural ISV with its facetted structure and presumed underlying neural processes.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Neuroscience and Mental Health Research Institute (NMHRI) Medicine MRC Centre for Neuropsychiatric Genetics and Genomics (CNGG)
Publisher:	Elsevier
ISSN:	0278-2626
Date of First Compliant Deposit:	21 January 2020
Date of Acceptance:	16 March 2019
Last Modified:	08 Nov 2023 02:11
URI:	https://orca.cardiff.ac.uk/id/eprint/128884

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