Daniël Roelfs

• Tissink, E.P.; Shadrin, Alexey; van der Meer, Dennis; Parker, Nadine; Hindley, Guy & Roelfs, Daniel [Vis alle 18 forfattere av denne artikkelen] (2024). Abundant pleiotropy across neuroimaging modalities identified through a multivariate genome-wide association study. Nature Communications. ISSN 2041-1723. 15(1). doi: 10.1038/s41467-024-46817-4.
• Roelfs, Daniel; Frei, Oleksandr; van der Meer, Dennis; Tissink, Elleke; Shadrin, Alexey & Alnæs, Dag [Vis alle 9 forfattere av denne artikkelen] (2023). Shared genetic architecture between mental health and the brain functional connectome in the UK Biobank. BMC Psychiatry. ISSN 1471-244X. 23(1). doi: 10.1186/s12888-023-04905-7. Fulltekst i vitenarkiv
• Slapø, Nora Berz; Nerland, Stener; Jørgensen, Kjetil Nordbø; Mørch-Johnsen, Lynn Egeland; Pettersen, Johanne Hagen & Roelfs, Daniel [Vis alle 22 forfattere av denne artikkelen] (2023). Auditory Cortex Thickness Is Associated With N100 Amplitude in Schizophrenia Spectrum Disorders. Schizophrenia Bulletin Open. ISSN 2632-7899. 4(1). doi: 10.1093/schizbullopen/sgad015. Fulltekst i vitenarkiv
• Slapø, Nora Berz; Jørgensen, Kjetil Nordbø; Elvsåshagen, Torbjørn; Nerland, Stener; Roelfs, Daniel & Valstad, Mathias [Vis alle 18 forfattere av denne artikkelen] (2023). Relationship between function and structure in the visual cortex in healthy individuals and in patients with severe mental disorders. Psychiatry Research : Neuroimaging. ISSN 0925-4927. 332. doi: 10.1016/j.pscychresns.2023.111633. Fulltekst i vitenarkiv Vis sammendrag

  Patients with schizophrenia spectrum disorders (SCZspect) and bipolar disorders (BD) show impaired function in the primary visual cortex (V1), indicated by altered visual evoked potential (VEP). While the neural substrate for altered VEP in these patients remains elusive, altered V1 structure may play a role. One previous study found a positive relationship between the amplitude of the P100 component of the VEP and V1 surface area, but not V1 thickness, in a small sample of healthy individuals. Here, we aimed to replicate these findings in a larger healthy control (HC) sample (n = 307) and to examine the same relationship in patients with SCZspect (n = 30) or BD (n = 45). We also compared the mean P100 amplitude, V1 surface area and V1 thickness between controls and patients and found no significant group differences. In HC only, we found a significant positive P100-V1 surface area association, while there were no significant P100-V1 thickness relationships in HC, SCZspect or BD. Together, our results confirm previous findings of a positive P100-V1 surface area association in HC, whereas larger patient samples are needed to further clarify the function-structure relationship in V1 in SCZspect and BD.

• Sæther, Linn Sofie; Ueland, Thor; Haatveit, Beathe; Maglanoc, Luigi Angelo; Szabo, Attila & Djurovic, Srdjan [Vis alle 15 forfattere av denne artikkelen] (2022). Inflammation and cognition in severe mental illness: patterns of covariation and subgroups. Molecular Psychiatry. ISSN 1359-4184. doi: 10.1038/s41380-022-01924-w.
• Sæther, Linn Sofie; Ueland, Thor; Haatveit, Beathe; Maglanoc, Luigi; Szabo, Attila & Djurovic, Srdjan [Vis alle 14 forfattere av denne artikkelen] (2022). Inflammation and cognition in severe mental illness: patterns of covariation and subgroups. Molecular Psychiatry. ISSN 1359-4184. 8, s. 1284–1292. doi: 10.1038/s41380-022-01924-w. Fulltekst i vitenarkiv
• Hindley, Guy; Frei, Oleksandr; Shadrin, Alexey; Cheng, Weiqiu; O'Connell, Kevin Sean & Icick, Romain [Vis alle 17 forfattere av denne artikkelen] (2022). Charting the Landscape of Genetic Overlap Between Mental Disorders and Related Traits Beyond Genetic Correlation. American Journal of Psychiatry. ISSN 0002-953X. 179(11), s. 833–843. doi: 10.1176/appi.ajp.21101051.
• Voldsbekk, Irene; Bjørnerud, Atle; Groote, Inge Rasmus; Zak, Nathalia; Roelfs, Daniël & Maximov, Ivan [Vis alle 18 forfattere av denne artikkelen] (2022). Evidence for widespread alterations in cortical microstructure after 32 h of sleep deprivation. Translational Psychiatry. ISSN 2158-3188. 12(161). doi: 10.1038/s41398-022-01909-x. Fulltekst i vitenarkiv
• van der Meer, Dennis; Kaufmann, Tobias; Shadrin, Alexey; Makowski, Carolina; Frei, Oleksandr & Roelfs, Daniel [Vis alle 17 forfattere av denne artikkelen] (2021). The genetic architecture of human cortical folding. Science Advances. ISSN 2375-2548. 7(51), s. 1–9. doi: 10.1126/sciadv.abj9446. Fulltekst i vitenarkiv
• Valstad, Mathias; Roelfs, Daniel; Slapø, Nora Berz; Timpe, Clara Marie Fides; Rai, Ahsan & Matziorinis, Anna Maria [Vis alle 24 forfattere av denne artikkelen] (2021). Evidence for Reduced Long-Term Potentiation-Like Visual Cortical Plasticity in Schizophrenia and Bipolar Disorder. Schizophrenia Bulletin. ISSN 0586-7614. 47(6), s. 1751–1760. doi: 10.1093/schbul/sbab049. Fulltekst i vitenarkiv
• Roelfs, Daniel; Alnæs, Dag; Frei, Oleksandr; van der Meer, Dennis; Smeland, Olav Bjerkehagen & Andreassen, Ole Andreas [Vis alle 8 forfattere av denne artikkelen] (2021). Phenotypically independent profiles relevant to mental health are genetically correlated. Translational Psychiatry. ISSN 2158-3188. 11(1). doi: 10.1038/s41398-021-01313-x. Fulltekst i vitenarkiv Vis sammendrag

  Genome-wide association studies (GWAS) and family-based studies have revealed partly overlapping genetic architectures between various psychiatric disorders. Given clinical overlap between disorders, our knowledge of the genetic architectures underlying specific symptom profiles and risk factors is limited. Here, we aimed to derive distinct profiles relevant to mental health in healthy individuals and to study how these genetically relate to each other and to common psychiatric disorders. Using independent component analysis, we decomposed self-report mental health questionnaires from 136,678 healthy individuals of the UK Biobank, excluding data from individuals with a diagnosed neurological or psychiatric disorder, into 13 distinct profiles relevant to mental health, capturing different symptoms as well as social and risk factors underlying reduced mental health. Utilizing genotypes from 117,611 of those individuals with White British ancestry, we performed GWAS for each mental health profile and assessed genetic correlations between these profiles, and between the profiles and common psychiatric disorders and cognitive traits. We found that mental health profiles were genetically correlated with a wide range of psychiatric disorders and cognitive traits, with strongest effects typically observed between a given mental health profile and a disorder for which the profile is common (e.g. depression symptoms and major depressive disorder, or psychosis and schizophrenia). Strikingly, although the profiles were phenotypically uncorrelated, many of them were genetically correlated with each other. This study provides evidence that statistically independent mental health profiles partly share genetic underpinnings and show genetic overlap with psychiatric disorders, suggesting that shared genetics across psychiatric disorders cannot be exclusively attributed to the known overlapping symptomatology between the disorders.

• Voldsbekk, Irene; Groote, Inge Rasmus; Zak, Nathalia; Roelfs, Daniël Thomas Heimen; Geier, Oliver & Due-Tønnessen, Paulina [Vis alle 14 forfattere av denne artikkelen] (2021). Sleep and sleep deprivation differentially alter white matter microstructure: A mixed model design utilising advanced diffusion modelling. NeuroImage. ISSN 1053-8119. 226. doi: 10.1016/j.neuroimage.2020.117540. Fulltekst i vitenarkiv Vis sammendrag

  Sleep deprivation influences several critical functions, yet how it affects human brain white matter (WM) is not well understood. The aim of the present work was to investigate the effect of 32 hours of sleep deprivation on WM microstructure compared to changes observed in a normal sleep-wake cycle (SWC). To this end, we utilised diffusion weighted imaging (DWI) including the diffusion tensor model, diffusion kurtosis imaging and the spherical mean technique, a novel biophysical diffusion model. 46 healthy adults (23 sleep deprived vs 23 with normal SWC) underwent DWI across four time points (morning, evening, next day morning and next day afternoon, after a total of 32 hours). Linear mixed models revealed significant group × time interaction effects, indicating that sleep deprivation and normal SWC differentially affect WM microstructure. Voxel-wise comparisons showed that these effects spanned large, bilateral WM regions. These findings provide important insight into how sleep deprivation affects the human brain

• Sæther, Linn Sofie; Roelfs, Daniël Thomas Heimen; Moberget, Torgeir; Andreassen, Ole Andreas; Elvsåshagen, Torbjørn & Jönsson, Erik Gunnar [Vis alle 7 forfattere av denne artikkelen] (2020). Exploring neurophysiological markers of visual perspective taking: Methodological considerations. International Journal of Psychophysiology. ISSN 0167-8760. doi: 10.1016/j.ijpsycho.2020.12.006. Fulltekst i vitenarkiv Vis sammendrag

  Rationale: For visual perspective taking (VPT) using the avatar task, examinations of neural processes using event related potentials (ERP) indicate a distinction between an early posterior perspective calculation process (P3) and a later frontal process (LFSW) managing perspective conflict. While it is unknown if these neural processes are affected in clinical populations, it is unclear if the avatar task can be applied to this group, due to the long duration and sensitivity to data loss. Thus, we performed a methodological study of the avatar task, testing the feasibility of a shortened experimental paradigm. Objective: To investigate whether previously reported behavioural and ERP effects in the avatar task can also be seen if analysing all trials (matching/non-matching) jointly, and whether they remain robust if only a subset of the data is analysed. Method: Healthy individuals (n = 20) completed the avatar task with ERP measurement. ERP components (P3, LFSW) and behavioural data were investigated by A) comparing use of only matching trials (n = 384) versus all trials (n = 768), and B) examining if reduced duration of assessment, by analysing only a subset of the data, impacts ERP findings. Results: We observed minimal differences when analysing data from only matching trial types compared to all trial types. Further, ERP amplitudes and latency findings were replicated when analysing only a subset of the data. Conclusions: The duration of the avatar task can be reduced to avoid long testing times, thus making it better suited for use in clinical populations.

• Valstad, Mathias; Moberget, Torgeir; Roelfs, Daniël Thomas Heimen; Slapø, Nora Berz; Timpe, Clara Marie Fides & Beck, Dani [Vis alle 18 forfattere av denne artikkelen] (2020). Experience-dependent modulation of the visual evoked potential: Testing effect sizes, retention over time, and associations with age in 415 healthy individuals. NeuroImage. ISSN 1053-8119. doi: 10.1016/j.neuroimage.2020.117302. Fulltekst i vitenarkiv
• Voldsbekk, Irene; Maximov, Ivan; Zak, Nathalia; Roelfs, Daniël Thomas Heimen; Geier, Oliver & Due-Tønnessen, Paulina [Vis alle 10 forfattere av denne artikkelen] (2020). Evidence for wakefulness-related changes to extracellular space in human brain white matter from diffusion-weighted MRI. NeuroImage. ISSN 1053-8119. 212. doi: 10.1016/j.neuroimage.2020.116682. Fulltekst i vitenarkiv

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• Voldsbekk, Irene; Groote, Inge Rasmus; Zak, Nathalia; Roelfs, Daniël; Geier, Oliver & Due-Tønnessen, Paulina [Vis alle 14 forfattere av denne artikkelen] (2023). Corrigendum to “Sleep and sleep deprivation differentially alter white matter microstructure: A mixed model design utilising advanced diffusion modelling”. NeuroImage. ISSN 1053-8119. 270. doi: 10.1016/j.neuroimage.2023.119939.
• Voldsbekk, Irene; Roelfs, Daniël Thomas Heimen; Bjørnerud, Atle; Groote, Inge Rasmus & Maximov, Ivan (2019). White matter microstructure changes as a function of time-of-day: a biomarker of accumulating sleep pressure?

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