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Tissink EP, Shadrin AA, van der Meer D, Parker N, Hindley G, Roelfs D, Frei O, Fan CC, Nagel M, Nærland T, Budisteanu M, Djurovic S, Westlye LT, van den Heuvel MP, Posthuma D, Kaufmann T, Dale AM, Andreassen OA. Abundant pleiotropy across neuroimaging modalities identified through a multivariate genome-wide association study. Nat Commun 2024; 15:2655. [PMID: 38531894 DOI: 10.1038/s41467-024-46817-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
Genetic pleiotropy is abundant across spatially distributed brain characteristics derived from one neuroimaging modality (e.g. structural, functional or diffusion magnetic resonance imaging [MRI]). A better understanding of pleiotropy across modalities could inform us on the integration of brain function, micro- and macrostructure. Here we show extensive genetic overlap across neuroimaging modalities at a locus and gene level in the UK Biobank (N = 34,029) and ABCD Study (N = 8607). When jointly analysing phenotypes derived from structural, functional and diffusion MRI in a genome-wide association study (GWAS) with the Multivariate Omnibus Statistical Test (MOSTest), we boost the discovery of loci and genes beyond previously identified effects for each modality individually. Cross-modality genes are involved in fundamental biological processes and predominantly expressed during prenatal brain development. We additionally boost prediction of psychiatric disorders by conditioning independent GWAS on our multimodal multivariate GWAS. These findings shed light on the shared genetic mechanisms underlying variation in brain morphology, functional connectivity, and tissue composition.
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Affiliation(s)
- E P Tissink
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, 1081 HV, Amsterdam, The Netherlands.
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
| | - A A Shadrin
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
| | - D van der Meer
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
- School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - N Parker
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
| | - G Hindley
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
- Psychosis Studies, Institute of Psychiatry, Psychology and Neurosciences, King's College London, 16 De Crespigny Park, London, SE5 8AB, United Kingdom
| | - D Roelfs
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
| | - O Frei
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
| | - C C Fan
- Laureate Institute for Brain Research, Tulsa, OK, USA
- Department of Radiology, University of California San Diego, La Jolla, CA, 92037, USA
| | - M Nagel
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, 1081 HV, Amsterdam, The Netherlands
| | - T Nærland
- K.G. Jebsen Centre for Neurodevelopmental disorders, Division of Paediatric Medicine, Institute of Clinical Medicine, University of Oslo, Building 31, Oslo, Norway
| | - M Budisteanu
- Prof. Dr. Alex Obregia Clinical Hospital of Psychiatry, Bucharest, Romania
- "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - S Djurovic
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
- K.G. Jebsen Centre for Neurodevelopmental disorders, Division of Paediatric Medicine, Institute of Clinical Medicine, University of Oslo, Building 31, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - L T Westlye
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
- K.G. Jebsen Centre for Neurodevelopmental disorders, Division of Paediatric Medicine, Institute of Clinical Medicine, University of Oslo, Building 31, Oslo, Norway
- Department of Psychology, University of Oslo, Oslo, Norway
| | - M P van den Heuvel
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, 1081 HV, Amsterdam, The Netherlands
- Department of Child and Adolescent Psychology and Psychiatry, section Complex Trait Genetics, Amsterdam Neuroscience, VU University Medical Centre, Amsterdam, The Netherlands
| | - D Posthuma
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, 1081 HV, Amsterdam, The Netherlands
- Department of Child and Adolescent Psychology and Psychiatry, section Complex Trait Genetics, Amsterdam Neuroscience, VU University Medical Centre, Amsterdam, The Netherlands
| | - T Kaufmann
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany
| | - A M Dale
- Department of Radiology, University of California San Diego, La Jolla, CA, 92037, USA
- Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, CA, 92037, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92037, USA
| | - O A Andreassen
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Building 48, Oslo, Norway.
- K.G. Jebsen Centre for Neurodevelopmental disorders, Division of Paediatric Medicine, Institute of Clinical Medicine, University of Oslo, Building 31, Oslo, Norway.
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van der Meer D, Chovet L, Bera A, Richard A, Sánchez Cuevas PJ, Sánchez-Ibáñez JR, Olivares-Mendez M. REALMS: Resilient exploration and lunar mapping system. Front Robot AI 2023; 10:1127496. [PMID: 37064576 PMCID: PMC10097953 DOI: 10.3389/frobt.2023.1127496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Space resource utilisation is opening a new space era. The scientific proof of the presence of water ice on the south pole of the Moon, the recent advances in oxygen extraction from lunar regolith, and its use as a material to build shelters are positioning the Moon, again, at the centre of important space programs. These worldwide programs, led by ARTEMIS, expect robotics to be the disrupting technology enabling humankind’s next giant leap. However, Moon robots require a high level of autonomy to perform lunar exploration tasks more efficiently without being constantly controlled from Earth. Furthermore, having more than one robotic system will increase the resilience and robustness of the global system, improving its success rate, as well as providing additional redundancy. This paper introduces the Resilient Exploration and Lunar Mapping System, developed with a scalable architecture for semi-autonomous lunar mapping. It leverages Visual Simultaneous Localization and Mapping techniques on multiple rovers to map large lunar environments. Several resilience mechanisms are implemented, such as two-agent redundancy, delay invariant communications, a multi-master architecture different control modes. This study presents the experimental results of REALMS with two robots and its potential to be scaled to a larger number of robots, increasing the map coverage and system redundancy. The system’s performance is verified and validated in a lunar analogue facility, and a larger lunar environment during the European Space Agency (ESA)-European Space Resources Innovation Centre Space Resources Challenge. The results of the different experiments show the efficiency of REALMS and the benefits of using semi-autonomous systems.
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Affiliation(s)
- D. van der Meer
- Space Robotics (SpaceR) Research Group, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
- *Correspondence: D. van der Meer,
| | - L. Chovet
- Space Robotics (SpaceR) Research Group, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
| | - A. Bera
- Space Robotics (SpaceR) Research Group, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
| | - A. Richard
- Space Robotics (SpaceR) Research Group, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
| | | | - J. R. Sánchez-Ibáñez
- Guidance Navigation and Control Department, Airbus Defence and Space Ltd., Stevenage, United Kingdom
| | - M. Olivares-Mendez
- Space Robotics (SpaceR) Research Group, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
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Beztsinna N, Grillet F, Jariani A, Overkamp J, van der Meer D, Daszkiewicz L, Yan K, Vader W, Price L. ‘In vitro clinical trials’ platform for drug testing in patient-derived ex vivo 3D cultured human tumor tissues. Eur J Cancer 2020. [DOI: 10.1016/s0959-8049(20)31235-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kaufmann T, van der Meer D, Alnæs D, Frei O, Smeland O, Andreassen O, Westlye L. FV 19 Using cortico-genetic mapping to identify deviations from the norm in the developing brain. Clin Neurophysiol 2019. [DOI: 10.1016/j.clinph.2019.04.629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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van der Meer D, Hoekstra PJ, van Donkelaar M, Bralten J, Oosterlaan J, Heslenfeld D, Faraone SV, Franke B, Buitelaar JK, Hartman CA. Predicting attention-deficit/hyperactivity disorder severity from psychosocial stress and stress-response genes: a random forest regression approach. Transl Psychiatry 2017; 7:e1145. [PMID: 28585928 PMCID: PMC5537639 DOI: 10.1038/tp.2017.114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 12/20/2022] Open
Abstract
Identifying genetic variants contributing to attention-deficit/hyperactivity disorder (ADHD) is complicated by the involvement of numerous common genetic variants with small effects, interacting with each other as well as with environmental factors, such as stress exposure. Random forest regression is well suited to explore this complexity, as it allows for the analysis of many predictors simultaneously, taking into account any higher-order interactions among them. Using random forest regression, we predicted ADHD severity, measured by Conners' Parent Rating Scales, from 686 adolescents and young adults (of which 281 were diagnosed with ADHD). The analysis included 17 374 single-nucleotide polymorphisms (SNPs) across 29 genes previously linked to hypothalamic-pituitary-adrenal (HPA) axis activity, together with information on exposure to 24 individual long-term difficulties or stressful life events. The model explained 12.5% of variance in ADHD severity. The most important SNP, which also showed the strongest interaction with stress exposure, was located in a region regulating the expression of telomerase reverse transcriptase (TERT). Other high-ranking SNPs were found in or near NPSR1, ESR1, GABRA6, PER3, NR3C2 and DRD4. Chronic stressors were more influential than single, severe, life events. Top hits were partly shared with conduct problems. We conclude that random forest regression may be used to investigate how multiple genetic and environmental factors jointly contribute to ADHD. It is able to implicate novel SNPs of interest, interacting with stress exposure, and may explain inconsistent findings in ADHD genetics. This exploratory approach may be best combined with more hypothesis-driven research; top predictors and their interactions with one another should be replicated in independent samples.
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Affiliation(s)
- D van der Meer
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands,K.G. Jebsen Centre for Psychosis Research/Norwegian Centre for Mental Disorder Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway,Department of Psychiatry, University of Groningen, University Medical Center Groningen, PO Box 30001, 9700 RB Groningen, The Netherlands. E-mail:
| | - P J Hoekstra
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M van Donkelaar
- Department of Human Genetics and Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Bralten
- Department of Human Genetics and Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Oosterlaan
- Department of Clinical Neuropsychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - D Heslenfeld
- Department of Clinical Neuropsychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - S V Faraone
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, USA,Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA,K.G. Jebsen Centre for Psychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - B Franke
- Department of Human Genetics and Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J K Buitelaar
- Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - C A Hartman
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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van der Meer D, Hoekstra PJ, Bralten J, van Donkelaar M, Heslenfeld DJ, Oosterlaan J, Faraone SV, Franke B, Buitelaar JK, Hartman CA. Interplay between stress response genes associated with attention-deficit hyperactivity disorder and brain volume. Genes Brain Behav 2016; 15:627-36. [PMID: 27391809 DOI: 10.1111/gbb.12307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/15/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022]
Abstract
The glucocorticoid receptor plays a pivotal role in the brain's response to stress; a haplotype of functional polymorphisms in the NR3C1 gene encoding this receptor has been associated with attention-deficit hyperactivity disorder (ADHD). The serotonin transporter (5-HTT) gene polymorphism 5-HTTLPR is known to influence the relation between stress exposure and ADHD severity, which may be partly because of its reported effects on glucocorticoid levels. We therefore investigated if NR3C1 moderates the relation of stress exposure with ADHD severity and brain structure, and the potential role of 5-HTTLPR. Neuroimaging, genetic and stress exposure questionnaire data were available for 539 adolescents and young adults participating in the multicenter ADHD cohort study NeuroIMAGE (average age: 17.2 years). We estimated the effects of genetic variation in NR3C1 and 5-HTT, stress exposure and their interactions on ADHD symptom count and gray matter volume. We found that individuals carrying the ADHD risk haplotype of NR3C1 showed significantly more positive relation between stress exposure and ADHD severity than non-carriers. This gene-environment interaction was significantly stronger for 5-HTTLPR L-allele homozygotes than for S-allele carriers. These two- and three-way interactions were reflected in the gray matter volume of the cerebellum, parahippocampal gyrus, intracalcarine cortex and angular gyrus. Our findings illustrate how genetic variation in the stress response pathway may influence the effects of stress exposure on ADHD severity and brain structure. The reported interplay between NR3C1 and 5-HTT may further explain some of the heterogeneity between studies regarding the role of these genes and hypothalamic-pituitary-adrenal axis activity in ADHD.
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Affiliation(s)
- D van der Meer
- Department of Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. .,Centre for Cognitive Neuroimaging, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - P J Hoekstra
- Department of Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - J Bralten
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - M van Donkelaar
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - D J Heslenfeld
- Clinical Neuropsychology Section, VU University Amsterdam, Amsterdam, the Netherlands
| | - J Oosterlaan
- Clinical Neuropsychology Section, VU University Amsterdam, Amsterdam, the Netherlands
| | - S V Faraone
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - B Franke
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - J K Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre.,Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, the Netherlands
| | - C A Hartman
- Department of Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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Richards JS, Arias Vásquez A, von Rhein D, van der Meer D, Franke B, Hoekstra PJ, Heslenfeld DJ, Oosterlaan J, Faraone SV, Buitelaar JK, Hartman CA. Adolescent behavioral and neural reward sensitivity: a test of the differential susceptibility theory. Transl Psychiatry 2016; 6:e771. [PMID: 27045841 PMCID: PMC4872395 DOI: 10.1038/tp.2016.37] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 12/27/2022] Open
Abstract
Little is known about the causes of individual differences in reward sensitivity. We investigated gene-environment interactions (GxE) on behavioral and neural measures of reward sensitivity, in light of the differential susceptibility theory. This theory states that individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments. Reward responses were assessed during a monetary incentive delay task in 178 participants with and 265 without attention-deficit/hyperactivity disorder (ADHD), from N=261 families. We examined interactions between variants in candidate plasticity genes (DAT1, 5-HTT and DRD4) and social environments (maternal expressed emotion and peer affiliation). HTTLPR short allele carriers showed the least reward speeding when exposed to high positive peer affiliation, but the most when faced with low positive peer affiliation or low maternal warmth. DAT1 10-repeat homozygotes displayed similar GxE patterns toward maternal warmth on general task performance. At the neural level, DRD4 7-repeat carriers showed the least striatal activation during reward anticipation when exposed to high maternal warmth, but the most when exposed to low warmth. Findings were independent of ADHD severity. Our results partially confirm the differential susceptibility theory and indicate the importance of positive social environments in reward sensitivity and general task performance for persons with specific genotypes.
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Affiliation(s)
- J S Richards
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands,Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands,Karakter Child and Adolescent Psychiatry University Centre, Reinier Postlaan 12, 6525 GC Nijmegen, The Netherlands. E-mail:
| | - A Arias Vásquez
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands,Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - D von Rhein
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - D van der Meer
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - B Franke
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands,Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - P J Hoekstra
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - D J Heslenfeld
- Department of Clinical Neuropsychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - J Oosterlaan
- Department of Clinical Neuropsychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - S V Faraone
- Departments of Psychiatry and of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - J K Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands,Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands
| | - C A Hartman
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Schweren LJS, Hartman CA, Zwiers MP, Heslenfeld DJ, van der Meer D, Franke B, Oosterlaan J, Buitelaar JK, Hoekstra PJ. Combined stimulant and antipsychotic treatment in adolescents with attention-deficit/hyperactivity disorder: a cross-sectional observational structural MRI study. Eur Child Adolesc Psychiatry 2015; 24:959-68. [PMID: 25395383 DOI: 10.1007/s00787-014-0645-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 11/01/2014] [Indexed: 10/24/2022]
Abstract
Meta-analyses suggest normalizing effects of methylphenidate on structural fronto-striatal abnormalities in patients with attention-deficit/hyperactivity disorder (ADHD). A subgroup of patients receives atypical antipsychotics concurrent with methylphenidate. Long-term safety and efficacy of combined treatment are unknown. The current study provides an initial investigation of structural brain correlates of combined methylphenidate and antipsychotic treatment in patients with ADHD. Structural magnetic resonance imaging was obtained in 31 patients who had received combined methylphenidate and antipsychotic treatment, 31 matched patients who had received methylphenidate but not antipsychotics, and 31 healthy controls (M age 16.7 years). We analyzed between-group effects in total cortical and subcortical volume, and in seven frontal cortical and eight subcortical-limbic volumes of interest, each involved in dopaminergic neurotransmission. Patients in the combined treatment group, but not those in the methylphenidate only group, showed a reduction in total cortical volume compared to healthy controls (Cohen's d = 0.69, p < 0.004), which was apparent in most frontal volumes of interest. Further, the combined treatment group, but not the methylphenidate group, showed volume reduction in bilateral ventral diencephalon (Left Cohen's d = 0.48, p < 0.04; Right Cohen's d = 0.46, p < 0.05) and the left thalamus (Cohen's d = 0.47, p < 0.04). These findings may indicate antipsychotic treatment counteracting the normalizing effects of methylphenidate on brain structure. However, it cannot be ruled out that pre-existing clinical differences between both patient groups may have resulted in anatomical differences at the time of scanning. The absence of an untreated ADHD group hinders unequivocal interpretation and implications of our findings.
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Affiliation(s)
- L J S Schweren
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, Huispostcode CC10, 9700, VB, Groningen, The Netherlands,
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van der Meer D. Electrochemical reduction of aza aromatics. Part III: Reaction rate constants of the mononegative ions of the di-aza aromatics with water. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19700890109] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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van den Ham DMW, Harrison GFS, Spaans A, van der Meer D. Electrochemical reduction of aza-aromatics. Part V Influence of fluorine substitution on the electron affinities. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19750940708] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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van der Meer D, Feil D. Electrochemical reduction of aza aromatics. Part I. Polarographic reduction of aromatic di-aza compounds and correlation of results with H.M.O. calculations. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19680870703] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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van der Meer D, van der Weele K, Lohse D. Bifurcation diagram for compartmentalized granular gases. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 63:061304. [PMID: 11415089 DOI: 10.1103/physreve.63.061304] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2000] [Indexed: 05/23/2023]
Abstract
The bifurcation diagram for a vibrofluidized granular gas in N connected compartments is constructed and discussed. At vigorous driving, the uniform distribution (in which the gas is equi-partitioned over the compartments) is stable. But when the driving intensity is decreased this uniform distribution becomes unstable and gives way to a clustered state. For the simplest case, N=2, this transition takes place via a pitchfork bifurcation but for all N>2 the transition involves saddle-node bifurcations. The associated hysteresis becomes more and more pronounced for growing N. In the bifurcation diagram, apart from the uniform and the one-peaked distributions, also a number of multipeaked solutions occur. These are transient states. Their physical relevance is discussed in the context of a stability analysis.
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Affiliation(s)
- D van der Meer
- Department of Applied Physics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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