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.
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http://dx.doi.org/10.1016/j.bandc.2019.03.002 | DOI Listing |
Brain Cogn
June 2019
Department of Child and Adolescent Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, University of Freiburg, Germany; Department of Child and Adolescent Psychiatry, Medical Faculty, University of Cologne, Germany; Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece. Electronic address:
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.
View Article and Find Full Text PDFNeurosci Biobehav Rev
April 2017
Department of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Centre for Nonlinear Studies and The Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems (Hong Kong), Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Research Centre, HKBU Institute of Research and Continuing Education,Virtual University Park Building, South Area Hi-tech Industrial Park, Shenzhen, China; Beijing Computational Science Research Center, Beijing, China. Electronic address:
The intra-subject variability (ISV) in brain responses during cognitive processing across experimental trials has been recognised as an important facet of neural functionality reflecting an intrinsic neurophysiological characteristic of the brain. In recent decades, ISV in behaviour has been found to be significantly associated with cognitive functioning varying across individuals, development, ages, and pathological conditions. Event-related potentials (ERPs) measured in single trials are important tools for characterizing ISV at the neural level.
View Article and Find Full Text PDFMol Cell
August 2014
CNRS, Institut des Sciences du Végétal, Saclay Plant Sciences, 91198 Gif-sur-Yvette and Université Paris Diderot-Paris 7, 75013 Paris, France. Electronic address:
The eukaryotic epigenome is shaped by the genome topology in three-dimensional space. Dynamic reversible variations in this epigenome structure directly influence the transcriptional responses to developmental cues. Here, we show that the Arabidopsis long intergenic noncoding RNA (lincRNA) APOLO is transcribed by RNA polymerases II and V in response to auxin, a phytohormone controlling numerous facets of plant development.
View Article and Find Full Text PDFPLoS One
August 2014
Department Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany.
Increased intra-subject variability of reaction times (ISV-RT) is one of the most consistent findings in attention-deficit/hyperactivity disorder (ADHD). Although the nature of this phenomenon is still unclear, it has been hypothesised to reflect interference from the Default Mode Network (DMN). So far, ISV-RT has been operationally defined either as a frequency spectrum of the underlying RT time series, or as a measure of dispersion of the RT scores distribution.
View Article and Find Full Text PDFPhotosynth Res
January 2002
Institut des Sciences du Végétal (Institute of Plant Sciences), CNRS, bâtiment 24, F-91198, Gif-sur-Yvette cedex, France,
This article is not a survey of all the research made during the last half century at the 'Laboratoire de Photosynthèse' of the 'Centre National de la Recherche Scientifique' (CNRS) in Gif-sur-Yvette, but rather some personal recollections, as faithful as possible. Not all people could be mentioned and the scientists named here are mainly those who, at different stages of the laboratory's evolution, created their research teams, within or outside the laboratory. The laboratory, closed now as an administrative entity, was founded in 1953 by the CNRS in Gif-sur-Yvette, near Paris.
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