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Custodio RJP, Hengstler JG, Cheong JH, Kim HJ, Wascher E, Getzmann S. Adult ADHD: it is old and new at the same time - what is it? Rev Neurosci 2024; 35:225-241. [PMID: 37813870 DOI: 10.1515/revneuro-2023-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023]
Abstract
Even though the number of studies aiming to improve comprehension of ADHD pathology has increased in recent years, there still is an urgent need for more effective studies, particularly in understanding adult ADHD, both at preclinical and clinical levels, due to the increasing evidence that adult ADHD is highly distinct and a different entity from childhood ADHD. This review paper outlines the symptoms, diagnostics, and neurobiological mechanisms of ADHD, with emphasis on how adult ADHD could be different from childhood-onset. Data show a difference in the environmental, genetic, epigenetic, and brain structural changes, when combined, could greatly impact the behavioral presentations and the severity of ADHD in adults. Furthermore, a crucial aspect in the quest to fully understand this disorder could be through longitudinal analysis. In this way, we will determine if and how the pathology and pharmacology of ADHD change with age. This goal could revolutionize our understanding of the disorder and address the weaknesses in the current clinical classification systems, improving the characterization and validity of ADHD diagnosis, specifically those in adults.
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Affiliation(s)
- Raly James Perez Custodio
- Networking Group Aging, Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystrasse 67, Dortmund 44139, Germany
| | - Jan G Hengstler
- Systems Toxicology, Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystrasse 67, Dortmund 44139, Germany
| | - Jae Hoon Cheong
- Institute for New Drug Development, School of Pharmacy, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, South Korea
| | - Hee Jin Kim
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, 815 Hwarangro, Nowon-gu, Seoul 01795, South Korea
| | - Edmund Wascher
- Experimental Ergonomics, Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystrasse 67, Dortmund 44139, Germany
| | - Stephan Getzmann
- Networking Group Aging, Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystrasse 67, Dortmund 44139, Germany
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Chaumette B, Grizenko N, Fageera W, Fortier MÈ, Ter-Stepanian M, Labbe A, Joober R. Correlation of the methylomic signature of smoking during pregnancy with clinical traits in ADHD. J Psychiatry Neurosci 2023; 48:E390-E399. [PMID: 37857414 PMCID: PMC10599658 DOI: 10.1503/jpn.230062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/27/2023] [Accepted: 08/11/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent childhood disorder. Maternal smoking during pregnancy is a replicated environmental risk factor for this disorder. It is also a robust modifier of gene methylation during the prenatal developmental period. In this study, we sought to identify loci differentially methylated by maternal smoking during pregnancy and relate their methylation levels to various behavioural and physical outcomes relevant to ADHD. METHODS We extracted DNA from blood samples from children diagnosed with ADHD and deeply phenotyped. Genome-wide DNA methylation was assessed using Infinium MethylationEPIC BeadChip. Maternal smoking during pregnancy was self-declared and assessed retrospectively. RESULTS Our sample included 231 children with ADHD. Statistically significant differences in DNA methylation between children exposed or not to maternal smoking during pregnancy were detected in 3457 CpGs. We kept 30 CpGs with at least 5% of methylation difference between the 2 groups for further analysis. Six genes were associated with varied phenotypes of clinical relevance to ADHD. The levels of DNA methylation in RUNX1 were positively correlated with the CBCL scores, and DNA methylation in MYO1G correlated positively with the score at the Conners rating scale. Methylation level in a CpG located in GFI1 correlated with birthweight, a risk factor for ADHD. Differentially methylated regions were also identified and confirmed the association of RUNX1 methylation levels with the CBCL score. LIMITATIONS The study has several limitations, including the retrospective recall with self-report of maternal smoking during pregnancy as well as the grouping of individuals of varying age and developmental stage and of both males and females. In addition, the correlation design prevents the building of causation models. CONCLUSION This study provides evidence for the association between the level of methylation at specific loci and quantitative dimensions highly relevant for ADHD as well as birth weight, a measure that has already been associated with increased risk for ADHD. Our results provide further support to public health educational initiatives to stop maternal smoking during pregnancy.
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Affiliation(s)
- Boris Chaumette
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Natalie Grizenko
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Weam Fageera
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Marie-Ève Fortier
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Marina Ter-Stepanian
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Aurelie Labbe
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
| | - Ridha Joober
- From the Douglas Mental Health University Institute, Montréal, Que. (Chaumette, Grizenko, Fageerat, Fortier, Ter-Stepanian, Joober); the Department of Psychiatry, McGill University, Montréal, Que. (Chaumette, Grizenko, Joober); The Neuro, McGill University, Montréal, Que. (Chaumette); the Université Paris Cité, INSERM U1266, Institute of Psychiatry and Neuroscience of Paris, Paris, France (Chaumette); the GHU Paris Psychiatrie & Neurosciences, Paris, France (Chaumette); the Department of Human Genetics, McGill University, Montréal, Que. (Fageera, Joober); the Department of Educational and Counselling Psychology, McGill University, Montréal, Que. (Ter-Stepanian); the Département de Psychoéducation, Université de Sherbrooke, Que. (Ter-Stepanian); the Department of Decision Sciences, HEC Montreal, Montréal, Que. (Labbe); the Department of Neurology and Neurosurgery, McGill University, Montréal, Que. (Joober)
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Koohsari S, Sadabad FE, Pittman B, Gallezot JD, Carson RE, van Dyck CH, Li CSR, Potenza MN, Matuskey D. Relationships of in vivo brain norepinephrine transporter and age, BMI, and gender. Synapse 2023; 77:e22279. [PMID: 37382240 PMCID: PMC10416616 DOI: 10.1002/syn.22279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/30/2023]
Abstract
Previous research reported an age-related decline in brain norepinephrine transporter (NET) using (S, S)-[11C]O-methylreboxetine ([11C]MRB) as a radiotracer. Studies with the same tracer have been mixed in regard to differences related to body mass index (BMI). Here, we investigated potential age-, BMI-, and gender-related differences in brain NET availability using [11C]MRB, the most selective available radiotracer. Forty-three healthy participants (20 females, 23 males; age range 18-49 years), including 12 individuals with normal/lean weight, 15 with overweight, and 16 with obesity were scanned with [11C]MRB using a positron emission tomography (PET) high-resolution research tomograph (HRRT). We evaluated binding potential (BPND ) in brain regions with high NET availability using multilinear reference tissue model 2 (MRTM2) with the occipital cortex as a reference region. Brain regions were delineated with a defined anatomic template applied to subjects' structural MR scans. We found a negative association between age and NET availability in the locus coeruleus, raphe nucleus, and hypothalamus, with a 17%, 19%, and 14% decrease per decade, respectively, in each region. No gender or BMI relationships with NET availability were observed. Our findings suggest an age-related decline, but no BMI- or gender-related differences, in NET availability in healthy adults.
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Affiliation(s)
- Sheida Koohsari
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | | | - Brian Pittman
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut
| | | | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | | | - Chiang-Shan R Li
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut
| | - Marc N Potenza
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut
- Child Study Center, Yale School of Medicine, New Haven, Connecticut
- Department of Neuroscience, Yale University, New Haven, Connecticut
- Connecticut Council on Problem Gambling, Wethersfield, Connecticut
- Connecticut Mental Health Center, New Haven, Connecticut
- Wu Tsai Institute, Yale University, New Haven, Connecticut
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut
- Department of Neurology, Yale University, New Haven, Connecticut
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Galgani A, Bartolini E, D'Amora M, Faraguna U, Giorgi FS. The Central Noradrenergic System in Neurodevelopmental Disorders: Merging Experimental and Clinical Evidence. Int J Mol Sci 2023; 24:ijms24065805. [PMID: 36982879 PMCID: PMC10055776 DOI: 10.3390/ijms24065805] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
The aim of this article is to highlight the potential role of the locus-coeruleus-noradrenergic (LC-NA) system in neurodevelopmental disorders (NdDs). The LC is the main brain noradrenergic nucleus, key in the regulation of arousal, attention, and stress response, and its early maturation and sensitivity to perinatal damage make it an interesting target for translational research. Clinical data shows the involvement of the LC-NA system in several NdDs, suggesting a pathogenetic role in the development of such disorders. In this context, a new neuroimaging tool, LC Magnetic Resonance Imaging (MRI), has been developed to visualize the LC in vivo and assess its integrity, which could be a valuable tool for exploring morphological alterations in NdD in vivo in humans. New animal models may be used to test the contribution of the LC-NA system to the pathogenic pathways of NdD and to evaluate the efficacy of NA-targeting drugs. In this narrative review, we provide an overview of how the LC-NA system may represent a common pathophysiological and pathogenic mechanism in NdD and a reliable target for symptomatic and disease-modifying drugs. Further research is needed to fully understand the interplay between the LC-NA system and NdD.
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Affiliation(s)
- Alessandro Galgani
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
| | - Emanuele Bartolini
- Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
- Tuscany PhD Programme in Neurosciences, 50121 Florence, Italy
| | - Marta D'Amora
- Department of Biology, University of Pisa, 56125 Pisa, Italy
- Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Ugo Faraguna
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
- Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Filippo Sean Giorgi
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
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Chen H, Yang Y, Odisho D, Wu S, Yi C, Oliver BG. Can biomarkers be used to diagnose attention deficit hyperactivity disorder? Front Psychiatry 2023; 14:1026616. [PMID: 36970271 PMCID: PMC10030688 DOI: 10.3389/fpsyt.2023.1026616] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/14/2023] [Indexed: 03/10/2023] Open
Abstract
Currently, the diagnosis of attention deficit hyperactivity disorder (ADHD) is solely based on behavioral tests prescribed by the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). However, biomarkers can be more objective and accurate for diagnosis and evaluating treatment efficacy. Thus, this review aimed to identify potential biomarkers for ADHD. Search terms “ADHD,” and “biomarker” combined with one of “protein,” “blood/serum,” “gene,” and “neuro” were used to identify human and animal studies in PubMed, Ovid Medline, and Web of Science. Only papers in English were included. Potential biomarkers were categorized into radiographic, molecular, physiologic, or histologic markers. The radiographic analysis can identify specific activity changes in several brain regions in individuals with ADHD. Several molecular biomarkers in peripheral blood cells and some physiologic biomarkers were found in a small number of participants. There were no published histologic biomarkers for ADHD. Overall, most associations between ADHD and potential biomarkers were properly controlled. In conclusion, a series of biomarkers in the literature are promising as objective parameters to more accurately diagnose ADHD, especially in those with comorbidities that prevent the use of DSM-5. However, more research is needed to confirm the reliability of the biomarkers in larger cohort studies.
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Affiliation(s)
- Hui Chen
- Department of Pathology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Yang Yang
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Diana Odisho
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Siqi Wu
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Chenju Yi
- Department of Pathology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
- Shenzhen Key Laboratory of Chinese Medicine Active Substance Screening and Translational Research, Shenzhen, China
- *Correspondence: Chenju Yi,
| | - Brian G. Oliver
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
- Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia
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6
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The role of DNA methylation in progression of neurological disorders and neurodegenerative diseases as well as the prospect of using DNA methylation inhibitors as therapeutic agents for such disorders. IBRO Neurosci Rep 2022; 14:28-37. [PMID: 36590248 PMCID: PMC9794904 DOI: 10.1016/j.ibneur.2022.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/23/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Genome-wide studies related to neurological disorders and neurodegenerative diseases have pointed to the role of epigenetic changes such as DNA methylation, histone modification, and noncoding RNAs. DNA methylation machinery controls the dynamic regulation of methylation patterns in discrete brain regions. Objective This review aims to describe the role of DNA methylation in inhibiting and progressing neurological and neurodegenerative disorders and therapeutic approaches. Methods A Systematic search of PubMed, Web of Science, and Cochrane Library was conducted for all qualified studies from 2000 to 2022. Results For the current need of time, we have focused on the DNA methylation role in neurological and neurodegenerative diseases and the expression of genes involved in neurodegeneration such as Alzheimer's, Depression, and Rett Syndrome. Finally, it appears that the various epigenetic changes do not occur separately and that DNA methylation and histone modification changes occur side by side and affect each other. We focused on the role of modification of DNA methylation in several genes associated with depression (NR3C1, NR3C2, CRHR1, SLC6A4, BDNF, and FKBP5), Rett syndrome (MECP2), Alzheimer's, depression (APP, BACE1, BIN1 or ANK1) and Parkinson's disease (SNCA), as well as the co-occurring modifications to histones and expression of non-coding RNAs. Understanding these epigenetic changes and their interactions will lead to better treatment strategies. Conclusion This review captures the state of understanding of the epigenetics of neurological and neurodegenerative diseases. With new epigenetic mechanisms and targets undoubtedly on the horizon, pharmacological modulation and regulation of epigenetic processes in the brain holds great promise for therapy.
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Yamamoto M, Inada T. Positron emission tomography studies in adult patients with attention-deficit/hyperactivity disorder. Jpn J Radiol 2022; 41:382-392. [PMID: 36480104 DOI: 10.1007/s11604-022-01368-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, motor hyperactivity, impulsivity, and psychosocial as well as cognitive dysfunction. Although characteristic clinical manifestations have been described, no definitive biomarkers to diagnose ADHD have been established. In this review article, we summarize positron emission tomography (PET) studies conducted in adult patients with ADHD. We found that, although, disturbances of dopamine, serotonin, and norepinephrine functions have been implicated in ADHD, no characteristic findings have been identified from PET studies in patients with ADHD. Several previous PET studies on the central dopaminergic transmission-related ligands in patients with ADHD have shown altered binding of dopamine markers in the basal ganglia. However, no consistent results were observed in the binding characteristics for dopamine transporters and receptors. Findings from PET studies with ligands related to serotonin and norepinephrine pathways showed either unclear clinical significance or low replicability. Therefore, whether alterations of monoamine function may be involved in the pathophysiological mechanism remains to be clarified. The limitations of previous PET studies include their small sample sizes, focus on several kinds of existing ligands, and a questionable validity of the diagnosis (lack of biological diagnostic criteria). To determine the characteristic findings for diagnosing ADHD, further research is needed, and particularly, studies that evaluate new active ligands with specific binding to monoamine pathways should be undertaken.
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Affiliation(s)
- Maeri Yamamoto
- Department of Psychiatry, Nagoya University Hospital, 65 Tsurumai-Cho, Showa-Ku, Nagoya-Shi, Aichi, 466-8560, Japan
| | - Toshiya Inada
- Department of Psychiatry, Graduate School of Medicine, Nagoya University, 65 Tsurumai-Cho, Showa-Ku, Nagoya-Shi, Aichi, 466-8550, Japan.
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Reddy DS, Abeygunaratne HN. Experimental and Clinical Biomarkers for Progressive Evaluation of Neuropathology and Therapeutic Interventions for Acute and Chronic Neurological Disorders. Int J Mol Sci 2022; 23:11734. [PMID: 36233034 PMCID: PMC9570151 DOI: 10.3390/ijms231911734] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/27/2022] Open
Abstract
This article describes commonly used experimental and clinical biomarkers of neuronal injury and neurodegeneration for the evaluation of neuropathology and monitoring of therapeutic interventions. Biomarkers are vital for diagnostics of brain disease and therapeutic monitoring. A biomarker can be objectively measured and evaluated as a proxy indicator for the pathophysiological process or response to therapeutic interventions. There are complex hurdles in understanding the molecular pathophysiology of neurological disorders and the ability to diagnose them at initial stages. Novel biomarkers for neurological diseases may surpass these issues, especially for early identification of disease risk. Validated biomarkers can measure the severity and progression of both acute neuronal injury and chronic neurological diseases such as epilepsy, migraine, Alzheimer's disease, Parkinson's disease, Huntington's disease, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis, and other brain diseases. Biomarkers are deployed to study progression and response to treatment, including noninvasive imaging tools for both acute and chronic brain conditions. Neuronal biomarkers are classified into four core subtypes: blood-based, immunohistochemical-based, neuroimaging-based, and electrophysiological biomarkers. Neuronal conditions have progressive stages, such as acute injury, inflammation, neurodegeneration, and neurogenesis, which can serve as indices of pathological status. Biomarkers are critical for the targeted identification of specific molecules, cells, tissues, or proteins that dramatically alter throughout the progression of brain conditions. There has been tremendous progress with biomarkers in acute conditions and chronic diseases affecting the central nervous system.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
- Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
- Intercollegiate School of Engineering Medicine, Texas A&M University, Houston, TX 77030, USA
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Hasara Nethma Abeygunaratne
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
- Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
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Silk T, Dipnall L, Wong YT, Craig JM. Epigenetics and ADHD. Curr Top Behav Neurosci 2022; 57:269-289. [PMID: 35505060 DOI: 10.1007/7854_2022_339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
There is robust evidence of genetic susceptibility to Attention-Deficit Hyperactivity Disorder (ADHD); however, there still remains significant variability that is not attributable to genetic factors. The emerging field of epigenetics is beginning to reveal how genotypic expression can be mediated by an array of variables including external environmental exposure, inter-individual developmental variation, and by the genome itself. Epigenetic modification plays a central role in neurobiological and developmental processes, and disturbances to these processes can have implications for a range of mental health problems. Although the field is still in its early days, this chapter will discuss the current standing of epigenetic research into ADHD. Firstly, key relevant epigenetic processes will be discussed. This will be followed by an overview of the key findings to date investigating the role of epigenetics in ADHD. Human studies have included the theory-driven approach of candidate-gene studies (CGS), as well as the increasingly popular exploratory approach of epigenome-wide association studies (EWAS). Overall, the findings are heterogeneous. However, it is possible that with more longitudinal studies and better characterised cohorts, both predictive and protective links between epigenetic processes and ADHD will be revealed.
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Affiliation(s)
- Timothy Silk
- Centre for Social and Early Emotional Development and School of Psychology, Deakin University, Geelong, VIC, Australia. .,Murdoch Children's Research Institute, Parkville, VIC, Australia.
| | - Lillian Dipnall
- Centre for Social and Early Emotional Development and School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Yen Ting Wong
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Jeffrey M Craig
- Murdoch Children's Research Institute, Parkville, VIC, Australia.,Institute for Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, VIC, Australia
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Peedicayil J. The Role of Epigenetics in the Pathogenesis and Potential Treatment of Attention Deficit Hyperactivity Disorder. Curr Neuropharmacol 2022; 20:1642-1650. [PMID: 34544344 PMCID: PMC9881064 DOI: 10.2174/1570159x19666210920091036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 11/22/2022] Open
Abstract
There is increasing evidence that dysregulated epigenetic mechanisms of gene expression are involved in the pathogenesis of attention deficit hyperactivity disorder (ADHD). This review presents a comprehensive summary of the current state of research on the role of epigenetics in the pathogenesis of ADHD. The potential role of epigenetic drugs in the treatment of ADHD is also reviewed. Several studies suggest that there are epigenetic abnormalities in preclinical models of ADHD and in ADHD patients. Regarding DNA methylation, many studies have reported DNA hypermethylation. There is evidence that there is increased histone deacetylation in ADHD patients. Abnormalities in the expression of microRNAs (miRNAs) in ADHD patients have also been found. Some currently used drugs for treating ADHD, in addition to their more well-established mechanisms of action, have been shown to alter epigenetic mechanisms of gene expression. Clinical trials of epigenetic drugs in patients with ADHD report favorable results. These data suggest that abnormal epigenetic mechanisms of gene expression may be involved in the pathogenesis of ADHD. Drugs acting on epigenetic mechanisms may be a potential new class of drugs for treating ADHD.
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Affiliation(s)
- Jacob Peedicayil
- Department of Pharmacology and Clinical Pharmacology, Christian Medical College, Vellore, India,Address correspondence to this author at the Department of Pharmacology and Clinical Pharmacology, Christian Medical College, Vellore, India;Tel: 91-0416-2284237; E-mail:
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11
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Slater C, Liu Y, Weiss E, Yu K, Wang Q. The Neuromodulatory Role of the Noradrenergic and Cholinergic Systems and Their Interplay in Cognitive Functions: A Focused Review. Brain Sci 2022; 12:890. [PMID: 35884697 PMCID: PMC9320657 DOI: 10.3390/brainsci12070890] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 12/15/2022] Open
Abstract
The noradrenergic and cholinergic modulation of functionally distinct regions of the brain has become one of the primary organizational principles behind understanding the contribution of each system to the diversity of neural computation in the central nervous system. Decades of work has shown that a diverse family of receptors, stratified across different brain regions, and circuit-specific afferent and efferent projections play a critical role in helping such widespread neuromodulatory systems obtain substantial heterogeneity in neural information processing. This review briefly discusses the anatomical layout of both the noradrenergic and cholinergic systems, as well as the types and distributions of relevant receptors for each system. Previous work characterizing the direct and indirect interaction between these two systems is discussed, especially in the context of higher order cognitive functions such as attention, learning, and the decision-making process. Though a substantial amount of work has been done to characterize the role of each neuromodulator, a cohesive understanding of the region-specific cooperation of these two systems is not yet fully realized. For the field to progress, new experiments will need to be conducted that capitalize on the modular subdivisions of the brain and systematically explore the role of norepinephrine and acetylcholine in each of these subunits and across the full range of receptors expressed in different cell types in these regions.
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Affiliation(s)
- Cody Slater
- Department of Biomedical Engineering, Columbia University, ET 351, 500 W. 120th Street, New York, NY 10027, USA; (C.S.); (Y.L.); (E.W.); (K.Y.)
- Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Yuxiang Liu
- Department of Biomedical Engineering, Columbia University, ET 351, 500 W. 120th Street, New York, NY 10027, USA; (C.S.); (Y.L.); (E.W.); (K.Y.)
| | - Evan Weiss
- Department of Biomedical Engineering, Columbia University, ET 351, 500 W. 120th Street, New York, NY 10027, USA; (C.S.); (Y.L.); (E.W.); (K.Y.)
| | - Kunpeng Yu
- Department of Biomedical Engineering, Columbia University, ET 351, 500 W. 120th Street, New York, NY 10027, USA; (C.S.); (Y.L.); (E.W.); (K.Y.)
| | - Qi Wang
- Department of Biomedical Engineering, Columbia University, ET 351, 500 W. 120th Street, New York, NY 10027, USA; (C.S.); (Y.L.); (E.W.); (K.Y.)
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12
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Nwokafor C, Serova LI, Tanelian A, Nahvi RJ, Sabban EL. Variable Response of Norepinephrine Transporter to Traumatic Stress and Relationship to Hyperarousal. Front Behav Neurosci 2021; 15:725091. [PMID: 34650410 PMCID: PMC8507558 DOI: 10.3389/fnbeh.2021.725091] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
The noradrenergic systems play a key role in stress triggered disorders such as post-traumatic stress disorder (PTSD). We hypothesized that traumatic stress will alter expression of norepinephrine transporter (NET) in locus coeruleus (LC) and its target brain regions which could be related to hyperarousal. Male Sprague-Dawley rats were subjected to single prolonged stress (SPS) and several weeks later the LC was isolated. NET mRNA levels in LC, determined by RT-PCR, displayed variable response with high and low responsive subgroups. In different cohort, acoustic startle response (ASR) was measured 2 weeks after SPS and levels of NET mRNA and protein in LC determined. The high NET responsive subgroup had greater hyperarousal. Nevertheless, NET protein levels, as determined by western blots, were lower than unstressed controls in LC, ventral hippocampus and medial prefrontal cortex and displayed considerable variability. Hypermethylation of specific CpG region in promoter of SLC6A2 gene, encoding NET, was present in the low, but not high, NET mRNA responsive subgroup. Taken together, the results demonstrate variability in stress elicited changes in NET gene expression and involvement of epigenetic changes. This may underlie mechanisms of susceptibility and resilience to traumatic stress triggered neuropsychiatric symptoms, especially hyperarousal.
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Affiliation(s)
- Chiso Nwokafor
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Lidia I Serova
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Arax Tanelian
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Roxanna J Nahvi
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Esther L Sabban
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
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13
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Höflich A, Kraus C, Pfeiffer RM, Seiger R, Rujescu D, Zarate CA, Kasper S, Winkler D, Lanzenberger R. Translating the immediate effects of S-Ketamine using hippocampal subfield analysis in healthy subjects-results of a randomized controlled trial. Transl Psychiatry 2021; 11:200. [PMID: 33795646 PMCID: PMC8016970 DOI: 10.1038/s41398-021-01318-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 02/17/2021] [Accepted: 03/05/2021] [Indexed: 12/28/2022] Open
Abstract
Antidepressant doses of ketamine rapidly facilitate synaptic plasticity and modify neuronal function within prefrontal and hippocampal circuits. However, most studies have demonstrated these effects in animal models and translational studies in humans are scarce. A recent animal study showed that ketamine restored dendritic spines in the hippocampal CA1 region within 1 h of administration. To translate these results to humans, this randomized, double-blind, placebo-controlled, crossover magnetic resonance imaging (MRI) study assessed ketamine's rapid neuroplastic effects on hippocampal subfield measurements in healthy volunteers. S-Ketamine vs. placebo data were analyzed, and data were also grouped by brain-derived neurotrophic factor (BDNF) genotype. Linear mixed models showed that overall hippocampal subfield volumes were significantly larger (p = 0.009) post ketamine than post placebo (LS means difference=0.008, standard error=0.003). Post-hoc tests did not attribute effects to specific subfields (all p > 0.05). Trend-wise volumetric increases were observed within the left hippocampal CA1 region (p = 0.076), and trend-wise volumetric reductions were obtained in the right hippocampal-amygdaloid transition region (HATA) (p = 0.067). Neither genotype nor a genotype-drug interaction significantly affected the results (all p > 0.7). The study provides evidence that ketamine has short-term effects on hippocampal subfield volumes in humans. The results translate previous findings from animal models of depression showing that ketamine has pro-neuroplastic effects on hippocampal structures and underscore the importance of the hippocampus as a key region in ketamine's mechanism of action.
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Affiliation(s)
- Anna Höflich
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Christoph Kraus
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria ,grid.94365.3d0000 0001 2297 5165Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD USA
| | - Ruth M. Pfeiffer
- grid.94365.3d0000 0001 2297 5165Biostatistics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA
| | - Rene Seiger
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Dan Rujescu
- grid.9018.00000 0001 0679 2801Department of Psychiatry, Psychotherapy and Psychosomatics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Carlos A. Zarate
- grid.94365.3d0000 0001 2297 5165Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD USA
| | - Siegfried Kasper
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Dietmar Winkler
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
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Differential attentional control mechanisms by two distinct noradrenergic coeruleo-frontal cortical pathways. Proc Natl Acad Sci U S A 2020; 117:29080-29089. [PMID: 33139568 DOI: 10.1073/pnas.2015635117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The attentional control of behavior is a higher-order cognitive function that operates through attention and response inhibition. The locus coeruleus (LC), the main source of norepinephrine in the brain, is considered to be involved in attentional control by modulating the neuronal activity of the prefrontal cortex (PFC). However, evidence for the causal role of LC activity in attentional control remains elusive. Here, by using behavioral and optogenetic techniques, we investigate the effect of LC neuron activation or inhibition in operant tests measuring attention and response inhibition (i.e., a measure of impulsive behavior). We show that LC neuron stimulation increases goal-directed attention and decreases impulsivity, while its suppression exacerbates distractibility and increases impulsive responding. Remarkably, we found that attention and response inhibition are under the control of two divergent projections emanating from the LC: one to the dorso-medial PFC and the other to the ventro-lateral orbitofrontal cortex, respectively. These findings are especially relevant for those pathological conditions characterized by attention deficits and elevated impulsivity.
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15
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DNA methylation associated with persistent ADHD suggests TARBP1 as novel candidate. Neuropharmacology 2020; 184:108370. [PMID: 33137342 DOI: 10.1016/j.neuropharm.2020.108370] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 10/07/2020] [Accepted: 10/23/2020] [Indexed: 12/25/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by age-inappropriate symptoms of inattention and/or hyperactivity and impulsivity. ADHD is highly prevalent in childhood and often persists into adulthood. Both genetic variants and environmental factors play a role in the onset and persistence of ADHD, and epigenetic changes, such as DNA methylation are considered as a link for their interplay. To investigate this, we studied DNA methylation in 37 candidate genes by performing targeted bisulfite sequencing of DNA isolated from whole blood of N = 88 individuals diagnosed with adult ADHD and N = 91 unaffected individuals (mean age 34.2 years). Differentially methylated sites were assessed by generalized linear models testing ADHD status and ADHD symptoms, accounting for a methylation-based smoking score, age, sex, and blood cell count. DNA methylation of single sites within DRD4 and KLDR1 was associated with adult ADHD status, and multiple DNA methylation sites within TARBP1 were associated with ADHD symptoms in adulthood and childhood. Awaiting replication, findings of this pilot study point to TARBP1 as a new candidate gene for ADHD symptoms. Our work also stresses the need for research to further examine the effects of environmental factors, such as nicotine exposure, on epigenetic modifications associated with psychiatric traits.
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16
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Dipasquale O, Martins D, Sethi A, Veronese M, Hesse S, Rullmann M, Sabri O, Turkheimer F, Harrison NA, Mehta MA, Cercignani M. Unravelling the effects of methylphenidate on the dopaminergic and noradrenergic functional circuits. Neuropsychopharmacology 2020; 45:1482-1489. [PMID: 32473593 PMCID: PMC7360745 DOI: 10.1038/s41386-020-0724-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/30/2020] [Accepted: 05/15/2020] [Indexed: 11/08/2022]
Abstract
Functional magnetic resonance imaging (fMRI) can be combined with drugs to investigate the system-level functional responses in the brain to such challenges. However, most psychoactive agents act on multiple neurotransmitters, limiting the ability of fMRI to identify functional effects related to actions on discrete pharmacological targets. We recently introduced a multimodal approach, REACT (Receptor-Enriched Analysis of functional Connectivity by Targets), which offers the opportunity to disentangle effects of drugs on different neurotransmitters and clarify the biological mechanisms driving clinical efficacy and side effects of a compound. Here, we focus on methylphenidate (MPH), which binds to the dopamine transporter (DAT) and the norepinephrine transporter (NET), to unravel its effects on dopaminergic and noradrenergic functional circuits in the healthy brain at rest. We then explored the relationship between these target-enriched resting state functional connectivity (FC) maps and inter-individual variability in behavioural responses to a reinforcement-learning task encompassing a novelty manipulation to disentangle the molecular systems underlying specific cognitive/behavioural effects. Our main analysis showed a significant MPH-induced FC increase in sensorimotor areas in the functional circuit associated with DAT. In our exploratory analysis, we found that MPH-induced regional variations in the DAT and NET-enriched FC maps were significantly correlated with some of the inter-individual differences on key behavioural responses associated with the reinforcement-learning task. Our findings show that main MPH-related FC changes at rest can be understood through the distribution of DAT in the brain. Furthermore, they suggest that when compounds have mixed pharmacological profiles, REACT may be able to capture regional functional effects that are underpinned by the same cognitive mechanism but are related to engagement of distinct molecular targets.
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Affiliation(s)
- Ottavia Dipasquale
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
| | - Daniel Martins
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Arjun Sethi
- Forensic & Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Swen Hesse
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University Medical Center, Leipzig, Germany
| | - Michael Rullmann
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University Medical Center, Leipzig, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Neil A Harrison
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, UK
| | - Mitul A Mehta
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Mara Cercignani
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, UK
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17
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Frankiensztajn LM, Elliott E, Koren O. The microbiota and the hypothalamus-pituitary-adrenocortical (HPA) axis, implications for anxiety and stress disorders. Curr Opin Neurobiol 2020; 62:76-82. [DOI: 10.1016/j.conb.2019.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/15/2019] [Accepted: 12/18/2019] [Indexed: 12/12/2022]
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18
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Recent advances in radiotracers targeting norepinephrine transporter: structural development and radiolabeling improvements. J Neural Transm (Vienna) 2020; 127:851-873. [PMID: 32274584 PMCID: PMC7223405 DOI: 10.1007/s00702-020-02180-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/21/2020] [Indexed: 12/13/2022]
Abstract
The norepinephrine transporter (NET) is a major target for the evaluation of the cardiac sympathetic nerve system in patients with heart failure and Parkinson's disease. It is also used in the therapeutic applications against certain types of neuroendocrine tumors, as exemplified by the clinically used 123/131I-MIBG as theranostic single-photon emission computed tomography (SPECT) agent. With the development of more advanced positron emission tomography (PET) technology, more radiotracers targeting NET have been reported, with superior temporal and spatial resolutions, along with the possibility of functional and kinetic analysis. More recently, fluorine-18-labelled NET tracers have drawn increasing attentions from researchers, due to their longer radiological half-life relative to carbon-11 (110 min vs. 20 min), reduced dependence on on-site cyclotrons, and flexibility in the design of novel tracer structures. In the heart, certain NET tracers provide integral diagnostic information on sympathetic innervation and the nerve status. In the central nervous system, such radiotracers can reveal NET distribution and density in pathological conditions. Most radiotracers targeting cardiac NET-function for the cardiac application consistent of derivatives of either norepinephrine or MIBG with its benzylguanidine core structure, e.g. 11C-HED and 18F-LMI1195. In contrast, all NET tracers used in central nervous system applications are derived from clinically used antidepressants. Lastly, possible applications of NET as selective tracers over organic cation transporters (OCTs) in the kidneys and other organs controlled by sympathetic nervous system will also be discussed.
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Groman SM. The Neurobiology of Impulsive Decision-Making and Reinforcement Learning in Nonhuman Animals. Curr Top Behav Neurosci 2020; 47:23-52. [PMID: 32157666 DOI: 10.1007/7854_2020_127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Impulsive decisions are those that favor immediate over delayed rewards, involve the acceptance of undue risk or uncertainty, or fail to adapt to environmental changes. Pathological levels of impulsive decision-making have been observed in individuals with mental illness, but there may be substantial heterogeneity in the processes that drive impulsive choices. Understanding this behavioral heterogeneity may be critical for understanding associated diverseness in the neural mechanisms that give rise to impulsivity. The application of reinforcement learning algorithms in the deconstruction of impulsive decision-making phenotypes can help bridge the gap between biology and behavior and provide insights into the biobehavioral heterogeneity of impulsive choice. This chapter will review the literature on the neurobiological mechanisms of impulsive decision-making in nonhuman animals; specifically, the role of the amine neuromodulatory systems (dopamine, serotonin, norepinephrine, and acetylcholine) in impulsive decision-making and reinforcement learning processes is discussed. Ultimately, the integration of reinforcement learning algorithms with sophisticated behavioral and neuroscience techniques may be critical for advancing the understanding of the neurochemical basis of impulsive decision-making.
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