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Mullin LJ, Rutsohn J, Gross JL, Caravella KE, Grzadzinski RL, Weisenfeld LA, Flake L, Botteron KN, Dager SR, Estes AM, Pandey J, Schultz RT, St John T, Wolff JJ, Shen MD, Piven J, Hazlett HC, Girault JB. Differential cognitive and behavioral development from 6 to 24 months in autism and fragile X syndrome. J Neurodev Disord 2024; 16:12. [PMID: 38509470 PMCID: PMC10953146 DOI: 10.1186/s11689-024-09519-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 02/14/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Specifying early developmental differences among neurodevelopmental disorders with distinct etiologies is critical to improving early identification and tailored intervention during the first years of life. Recent studies have uncovered important differences between infants with fragile X syndrome (FXS) and infants with familial history of autism spectrum disorder who go on to develop autism themselves (FH-ASD), including differences in brain development and behavior. Thus far, there have been no studies longitudinally investigating differential developmental skill profiles in FXS and FH-ASD infants. METHODS The current study contrasted longitudinal trajectories of verbal (expressive and receptive language) and nonverbal (gross and fine motor, visual reception) skills in FXS and FH-ASD infants, compared to FH infants who did not develop ASD (FH-nonASD) and typically developing controls. RESULTS Infants with FXS showed delays on a nonverbal composite compared to FH-ASD (as well as FH-nonASD and control) infants as early as 6 months of age. By 12 months an ordinal pattern of scores was established between groups on all domains tested, such that controls > FH-nonASD > FH-ASD > FXS. This pattern persisted through 24 months. Cognitive level differentially influenced developmental trajectories for FXS and FH-ASD. CONCLUSIONS Our results demonstrate detectable group differences by 6 months between FXS and FH-ASD as well as differential trajectories on each domain throughout infancy. This work further highlights an earlier onset of global cognitive delays in FXS and, conversely, a protracted period of more slowly emerging delays in FH-ASD. Divergent neural and cognitive development in infancy between FXS and FH-ASD contributes to our understanding of important distinctions in the development and behavioral phenotype of these two groups.
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Affiliation(s)
- Lindsay J Mullin
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA.
| | - Joshua Rutsohn
- Department of Biostatistics, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Julia L Gross
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Kelly E Caravella
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Rebecca L Grzadzinski
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Leigh Anne Weisenfeld
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Lisa Flake
- Department of Psychiatry, Washington University School of Medicine, St. Louis, USA
| | - Kelly N Botteron
- Department of Psychiatry, Washington University School of Medicine, St. Louis, USA
| | - Stephen R Dager
- Department of Radiology, University of Washington, Seattle, USA
- Center On Human Development and Disability, University of Washington, Seattle, USA
| | - Annette M Estes
- Center On Human Development and Disability, University of Washington, Seattle, USA
- Department of Speech and Hearing Sciences, University of Washington, Seattle, USA
| | - Juhi Pandey
- The Children's Hospital of Philadelphia and University of Pennsylvania, Center for Autism Research, Philadelphia, USA
| | - Robert T Schultz
- The Children's Hospital of Philadelphia and University of Pennsylvania, Center for Autism Research, Philadelphia, USA
| | - Tanya St John
- Center On Human Development and Disability, University of Washington, Seattle, USA
- Department of Speech and Hearing Sciences, University of Washington, Seattle, USA
| | - Jason J Wolff
- Department of Educational Psychology, University of Minnesota, Minneapolis, USA
| | - Mark D Shen
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, USA
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Joseph Piven
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Heather C Hazlett
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Jessica B Girault
- Carolina Institute for Developmental Disabilities, the University of North Carolina at Chapel Hill, Chapel Hill, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, USA
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Imbriglio T, Verhaeghe R, Antenucci N, Maccari S, Battaglia G, Nicoletti F, Cannella M. Developmental up-regulation of NMDA receptors in the prefrontal cortex and hippocampus of mGlu5 receptor knock-out mice. Mol Brain 2021; 14:77. [PMID: 33962661 PMCID: PMC8106212 DOI: 10.1186/s13041-021-00784-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/21/2021] [Indexed: 12/02/2022] Open
Abstract
mGlu5 metabotropic glutamate receptors are highly expressed and functional in the early postnatal life, and are known to positively modulate NMDA receptor function. Here, we examined the expression of NMDA receptor subunits and interneuron-related genes in the prefrontal cortex and hippocampus of mGlu5-/- mice and wild-type littermates at three developmental time points (PND9, - 21, and - 75). We were surprised to find that expression of all NMDA receptor subunits was greatly enhanced in mGlu5-/- mice at PND21. In contrast, at PND9, expression of the GluN2B subunit was enhanced, whereas expression of GluN2A and GluN2D subunits was reduced in both regions. These modifications were transient and disappeared in the adult life (PND75). Changes in the transcripts of interneuron-related genes (encoding parvalbumin, somatostatin, vasoactive intestinal peptide, reelin, and the two isoforms of glutamate decarboxylase) were also observed in mGlu5-/- mice across postnatal development. For example, the transcript encoding parvalbumin was up-regulated in the prefrontal cortex of mGlu5-/- mice at PND9 and PND21, whereas it was significantly reduced at PND75. These findings suggest that in mGlu5-/- mice a transient overexpression of NMDA receptor subunits may compensate for the lack of the NMDA receptor partner, mGlu5. Interestingly, in mGlu5-/- mice the behavioral response to the NMDA channel blocker, MK-801, was significantly increased at PND21, and largely reduced at PND75. The impact of adaptive changes in the expression of NMDA receptor subunits should be taken into account when mGlu5-/- mice are used for developmental studies.
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Affiliation(s)
| | | | - Nico Antenucci
- Department of Physiology and Pharmacology "V. Erspamer", University Sapienza of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy
| | - Stefania Maccari
- Department of Physiology and Pharmacology "V. Erspamer", University Sapienza of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy
- CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, University of Lille, Lille, France
| | - Giuseppe Battaglia
- IRCCS Neuromed, Pozzilli, IS, Italy
- Department of Physiology and Pharmacology "V. Erspamer", University Sapienza of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, IS, Italy.
- Department of Physiology and Pharmacology "V. Erspamer", University Sapienza of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy.
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Desarkar P, Rajji TK, Ameis SH, Blumberger DM, Lai MC, Lunsky Y, Daskalakis ZJ. Assessing and stabilizing atypical plasticity in autism spectrum disorder using rTMS: Results from a proof-of-principle study. Clin Neurophysiol 2021; 141:109-118. [PMID: 34011467 DOI: 10.1016/j.clinph.2021.03.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/08/2021] [Accepted: 03/05/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Emerging evidence implicates atypical plasticity in the neurophysiology of autism spectrum disorder (ASD). Specifically, autistic people demonstrated hyperplasticity in response to theta-burst stimulation (TBS). We hypothesized that autistic adults would display hyperplasticity to TBS and that repetitive transcranial magnetic stimulation (rTMS) - which potentiates brain inhibitory mechanisms - would 'stabilize' hyperplasticity. METHODS Using a randomized, cross-over design, plasticity was assessed using TBS in the left motor cortex (M1) in 31 autistic adults and 30 sex-, intelligence quotient-, and age-matched controls. Autistic adults (n = 29) were further randomized (1:1) to receive a single session of active (n = 14) or sham (n = 15) rTMS (6000 pulses at 20 Hz) over left M1 and plasticity was reassessed on the next day following rTMS. RESULTS Both long-term potentiation (LTP) and long-term depression (LTD) were significantly increased in the ASD group, indicating hyperplasticity. Active, but not sham rTMS, attenuated LTD in autistic adults. CONCLUSIONS We provided further evidence for the presence of brain hyperplasticity in ASD. To our knowledge, this is the first study to show preliminary evidence that an excessive LTD in ASD can be 'stabilized' using rTMS. Such 'stabilizing' effect of rTMS on LTP was not observed, likely due to small sample size or a more specific 'attenuating' effect of rTMS on LTD, compared to LTP. SIGNIFICANCE These findings indicate atypical brain inhibitory mechanisms behind hyperplasticity in ASD. Utilizing a larger sample, future replication studies could investigate therapeutic opportunities of 'mechanism-driven' rTMS.
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Affiliation(s)
- Pushpal Desarkar
- Azrieli Adult Neurodevelopmental Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Tarek K Rajji
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Stephanie H Ameis
- Azrieli Adult Neurodevelopmental Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON, Canada; The Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Daniel M Blumberger
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Meng-Chuan Lai
- Azrieli Adult Neurodevelopmental Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; The Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Yona Lunsky
- Azrieli Adult Neurodevelopmental Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zafiris J Daskalakis
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of California San Diego, San Diego, CA, USA
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4
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Perinatal Exposure to Diesel Exhaust-Origin Secondary Organic Aerosol Induces Autism-Like Behavior in Rats. Int J Mol Sci 2021; 22:ijms22020538. [PMID: 33430368 PMCID: PMC7828068 DOI: 10.3390/ijms22020538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/04/2021] [Accepted: 01/04/2021] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social communication, poor social interactions, and repetitive behaviors. We aimed to examine autism-like behaviors and related gene expressions in rats exposed to diesel exhaust (DE)-origin secondary organic aerosol (DE-SOA) perinatally. Sprague–Dawley pregnant rats were exposed to clean air (control), DE, and DE-SOA in the exposure chamber from gestational day 14 to postnatal day 21. Behavioral phenotypes of ASD were investigated in 10~13-week-old offspring using a three-chambered social behavior test, social dominance tube test, and marble burying test. Prefrontal cortex was collected to examine molecular analyses including neurological and immunological markers and glutamate concentration, using RT-PCR and ELISA methods. DE-SOA-exposed male and female rats showed poor sociability and social novelty preference, socially dominant behavior, and increased repetitive behavior. Serotonin receptor (5-HT(5B)) and brain-derived neurotrophic factor (BDNF) mRNAs were downregulated whereas interleukin 1 β (IL-β) and heme oxygenase 1 (HO-1) mRNAs were upregulated in the prefrontal cortex of male and female rats exposed to DE-SOA. Glutamate concentration was also increased significantly in DE-SOA-exposed male and female rats. Our results indicate that perinatal exposure to DE-SOA may induce autism-like behavior by modulating molecules such as neurological and immunological markers in rats.
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Lewis EM, Stein-O'Brien GL, Patino AV, Nardou R, Grossman CD, Brown M, Bangamwabo B, Ndiaye N, Giovinazzo D, Dardani I, Jiang C, Goff LA, Dölen G. Parallel Social Information Processing Circuits Are Differentially Impacted in Autism. Neuron 2020; 108:659-675.e6. [PMID: 33113347 PMCID: PMC8033501 DOI: 10.1016/j.neuron.2020.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/21/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023]
Abstract
Parallel processing circuits are thought to dramatically expand the network capabilities of the nervous system. Magnocellular and parvocellular oxytocin neurons have been proposed to subserve two parallel streams of social information processing, which allow a single molecule to encode a diverse array of ethologically distinct behaviors. Here we provide the first comprehensive characterization of magnocellular and parvocellular oxytocin neurons in male mice, validated across anatomical, projection target, electrophysiological, and transcriptional criteria. We next use novel multiple feature selection tools in Fmr1-KO mice to provide direct evidence that normal functioning of the parvocellular but not magnocellular oxytocin pathway is required for autism-relevant social reward behavior. Finally, we demonstrate that autism risk genes are enriched in parvocellular compared with magnocellular oxytocin neurons. Taken together, these results provide the first evidence that oxytocin-pathway-specific pathogenic mechanisms account for social impairments across a broad range of autism etiologies.
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Affiliation(s)
- Eastman M Lewis
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Genevieve L Stein-O'Brien
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, School of Medicine, Baltimore, MD 21205; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Alejandra V Patino
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Romain Nardou
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Cooper D Grossman
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Matthew Brown
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Bidii Bangamwabo
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Ndeye Ndiaye
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Daniel Giovinazzo
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Ian Dardani
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connie Jiang
- Cell and Molecular Biology Group, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Loyal A Goff
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Gül Dölen
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
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Bonnycastle K, Davenport EC, Cousin MA. Presynaptic dysfunction in neurodevelopmental disorders: Insights from the synaptic vesicle life cycle. J Neurochem 2020; 157:179-207. [PMID: 32378740 DOI: 10.1111/jnc.15035] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
Abstract
The activity-dependent fusion, retrieval and recycling of synaptic vesicles is essential for the maintenance of neurotransmission. Until relatively recently it was believed that most mutations in genes that were essential for this process would be incompatible with life, because of this fundamental role. However, an ever-expanding number of mutations in this very cohort of genes are being identified in individuals with neurodevelopmental disorders, including autism, intellectual disability and epilepsy. This article will summarize the current state of knowledge linking mutations in presynaptic genes to neurodevelopmental disorders by sequentially covering the various stages of the synaptic vesicle life cycle. It will also discuss how perturbations of specific stages within this recycling process could translate into human disease. Finally, it will also provide perspectives on the potential for future therapy that are targeted to presynaptic function.
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Affiliation(s)
- Katherine Bonnycastle
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
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7
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Crespi BJ. Comparative psychopharmacology of autism and psychotic-affective disorders suggests new targets for treatment. Evol Med Public Health 2019; 2019:149-168. [PMID: 31548888 PMCID: PMC6748779 DOI: 10.1093/emph/eoz022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/07/2019] [Indexed: 12/13/2022] Open
Abstract
The first treatments showing effectiveness for some psychiatric disorders, such as lithium for bipolar disorder and chlorpromazine for schizophrenia, were discovered by accident. Currently, psychiatric drug design is seen as a scientific enterprise, limited though it remains by the complexity of brain development and function. Relatively few novel and effective drugs have, however, been developed for many years. The purpose of this article is to demonstrate how evolutionary biology can provide a useful framework for psychiatric drug development. The framework is based on a diametrical nature of autism, compared with psychotic-affective disorders (mainly schizophrenia, bipolar disorder and depression). This paradigm follows from two inferences: (i) risks and phenotypes of human psychiatric disorders derive from phenotypes that have evolved along the human lineage and (ii) biological variation is bidirectional (e.g. higher vs lower, faster vs slower, etc.), such that dysregulation of psychological traits varies in two opposite ways. In this context, the author review the evidence salient to the hypothesis that autism and psychotic-affective disorders represent diametrical disorders in terms of current, proposed and potential psychopharmacological treatments. Studies of brain-derived neurotrophic factor, the PI3K pathway, the NMDA receptor, kynurenic acid metabolism, agmatine metabolism, levels of the endocannabinoid anandamide, antidepressants, anticonvulsants, antipsychotics, and other treatments, demonstrate evidence of diametric effects in autism spectrum disorders and phenotypes compared with psychotic-affective disorders and phenotypes. These findings yield insights into treatment mechanisms and the development of new pharmacological therapies, as well as providing an explanation for the longstanding puzzle of antagonism between epilepsy and psychosis. Lay Summary: Consideration of autism and schizophrenia as caused by opposite alterations to brain development and function leads to novel suggestions for pharmacological treatments.
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Affiliation(s)
- Bernard J Crespi
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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8
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Lieberman OJ, McGuirt AF, Tang G, Sulzer D. Roles for neuronal and glial autophagy in synaptic pruning during development. Neurobiol Dis 2018; 122:49-63. [PMID: 29709573 DOI: 10.1016/j.nbd.2018.04.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/22/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022] Open
Abstract
The dendritic protrusions known as spines represent the primary postsynaptic location for excitatory synapses. Dendritic spines are critical for many synaptic functions, and their formation, modification, and turnover are thought to be important for mechanisms of learning and memory. At many excitatory synapses, dendritic spines form during the early postnatal period, and while many spines are likely being formed and removed throughout life, the net number are often gradually "pruned" during adolescence to reach a stable level in the adult. In neurodevelopmental disorders, spine pruning is disrupted, emphasizing the importance of understanding its governing processes. Autophagy, a process through which cytosolic components and organelles are degraded, has recently been shown to control spine pruning in the mouse cortex, but the mechanisms through which autophagy acts remain obscure. Here, we draw on three widely studied prototypical synaptic pruning events to focus on two governing principles of spine pruning: 1) activity-dependent synaptic competition and 2) non-neuronal contributions. We briefly review what is known about autophagy in the central nervous system and its regulation by metabolic kinases. We propose a model in which autophagy in both neurons and non-neuronal cells contributes to spine pruning, and how other processes that regulate spine pruning could intersect with autophagy. We further outline future research directions to address outstanding questions on the role of autophagy in synaptic pruning.
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Affiliation(s)
- Ori J Lieberman
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States
| | - Avery F McGuirt
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States
| | - Guomei Tang
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, United States
| | - David Sulzer
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States; Department of Neurology, Columbia University Medical Center, New York, NY 10032, United States; Department of Pharmacology, Columbia University Medical Center, New York, NY 10032, United States; Research Foundation for Mental Hygiene, New York State Psychiatric Institute, New York, NY 10032, United States.
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9
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Kang E, Jiang D, Ryu YK, Lim S, Kwak M, Gray CD, Xu M, Choi JH, Junn S, Kim J, Xu J, Schaefer M, Johns RA, Song H, Ming GL, Mintz CD. Early postnatal exposure to isoflurane causes cognitive deficits and disrupts development of newborn hippocampal neurons via activation of the mTOR pathway. PLoS Biol 2017; 15:e2001246. [PMID: 28683067 PMCID: PMC5500005 DOI: 10.1371/journal.pbio.2001246] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 06/02/2017] [Indexed: 12/18/2022] Open
Abstract
Clinical and preclinical studies indicate that early postnatal exposure to anesthetics can lead to lasting deficits in learning and other cognitive processes. The mechanism underlying this phenomenon has not been clarified and there is no treatment currently available. Recent evidence suggests that anesthetics might cause persistent deficits in cognitive function by disrupting key events in brain development. The hippocampus, a brain region that is critical for learning and memory, contains a large number of neurons that develop in the early postnatal period, which are thus vulnerable to perturbation by anesthetic exposure. Using an in vivo mouse model we demonstrate abnormal development of dendrite arbors and dendritic spines in newly generated dentate gyrus granule cell neurons of the hippocampus after a clinically relevant isoflurane anesthesia exposure conducted at an early postnatal age. Furthermore, we find that isoflurane causes a sustained increase in activity in the mechanistic target of rapamycin pathway, and that inhibition of this pathway with rapamycin not only reverses the observed changes in neuronal development, but also substantially improves performance on behavioral tasks of spatial learning and memory that are impaired by isoflurane exposure. We conclude that isoflurane disrupts the development of hippocampal neurons generated in the early postnatal period by activating a well-defined neurodevelopmental disease pathway and that this phenotype can be reversed by pharmacologic inhibition. The United States Food and Drug Administration has recently warned that exposure to anesthetic and sedative drugs during the third trimester of prenatal development and during the first 3 years of life may cause lasting impairments in cognitive function. The mechanisms by which this undesirable side effect occurs are unknown. In this manuscript, we present evidence in mice that early developmental exposure to isoflurane, a canonical general anesthetic, disrupts the appropriate development of neurons in the hippocampus, a brain region associated with learning and memory. Isoflurane also causes up-regulation of the mechanistic target of rapamycin (mTOR) pathway, a signaling system that has been associated with other neurodevelopmental cognitive disorders. Treatment with an inhibitor of the mTOR pathway after isoflurane exposure normalizes neuronal development and also ameliorates the impairments in learning induced by isoflurane. We conclude that early exposure to isoflurane can cause learning deficits via actions on the mTOR pathway, and that this mechanism represents a potentially druggable target to minimize the side effects of anesthetics on the developing brain.
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Affiliation(s)
- Eunchai Kang
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Danye Jiang
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yun Kyoung Ryu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sanghee Lim
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Minhye Kwak
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Christy D. Gray
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michael Xu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jun H. Choi
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sue Junn
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jieun Kim
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jing Xu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michele Schaefer
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Roger A. Johns
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hongjun Song
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Guo-Li Ming
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - C. David Mintz
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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10
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Somatosensory map expansion and altered processing of tactile inputs in a mouse model of fragile X syndrome. Neurobiol Dis 2016; 96:201-215. [PMID: 27616423 DOI: 10.1016/j.nbd.2016.09.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 11/20/2022] Open
Abstract
Fragile X syndrome (FXS) is a common inherited form of intellectual disability caused by the absence or reduction of the fragile X mental retardation protein (FMRP) encoded by the FMR1 gene. In humans, one symptom of FXS is hypersensitivity to sensory stimuli, including touch. We used a mouse model of FXS (Fmr1 KO) to study sensory processing of tactile information conveyed via the whisker system. In vivo electrophysiological recordings in somatosensory barrel cortex showed layer-specific broadening of the receptive fields at the level of layer 2/3 but not layer 4, in response to whisker stimulation. Furthermore, the encoding of tactile stimuli at different frequencies was severely affected in layer 2/3. The behavioral effect of this broadening of the receptive fields was tested in the gap-crossing task, a whisker-dependent behavioral paradigm. In this task the Fmr1 KO mice showed differences in the number of whisker contacts with platforms, decrease in the whisker sampling duration and reduction in the whisker touch-time while performing the task. We propose that the increased excitability in the somatosensory barrel cortex upon whisker stimulation may contribute to changes in the whisking strategy as well as to other observed behavioral phenotypes related to tactile processing in Fmr1 KO mice.
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11
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Oberman LM, Ifert-Miller F, Najib U, Bashir S, Gonzalez-Heydrich J, Picker J, Rotenberg A, Pascual-Leone A. Abnormal Mechanisms of Plasticity and Metaplasticity in Autism Spectrum Disorders and Fragile X Syndrome. J Child Adolesc Psychopharmacol 2016; 26:617-24. [PMID: 27218148 PMCID: PMC5111832 DOI: 10.1089/cap.2015.0166] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES Multiple lines of evidence from genetic linkage studies to animal models implicate aberrant cortical plasticity and metaplasticity in the pathophysiology of autism spectrum disorder (ASD) and fragile X syndrome (FXS). However, direct experimental evidence of these alterations in humans with these disorders is scarce. Transcranial magnetic stimulation (TMS) is a noninvasive tool for probing mechanisms of plasticity and metaplasticity in vivo, in humans. The aim of the current study was to examine mechanisms of plasticity and metaplasticity in humans with ASD and FXS. We employed a repetitive TMS protocol developed specifically to probe cortical plasticity, namely continuous theta burst stimulation (cTBS). METHODS We applied a 40-second train of cTBS to primary motor cortex (M1) to healthy control participants and individuals with ASD or FXS, and we measured the cTBS-induced modulation in motor-evoked potentials (MEPs) in a contralateral intrinsic hand muscle. Each participant completed two sessions of the same protocol on two consecutive days. The degree of modulation in MEPs after cTBS on the first day was evaluated as a putative index of cortical plasticity. Examination of the changes in the effects of cTBS on the second day, as conditioned by the effects on the first day, provided an index of metaplasticity, or the propensity of a given cortical region to undergo plastic change based on its recent history. RESULTS After a 40-second cTBS train, individuals with ASD show a significantly longer duration of suppression in MEP amplitude as compared with healthy controls, whereas individuals with FXS show a significantly shorter duration. After a second train of cTBS, 24 hours later, the ASD group was indistinguishable from the control group, and while in the FXS group MEPs were paradoxically facilitated by cTBS. CONCLUSION These findings offer insights into the pathophysiology of ASD and FXS, specifically providing direct experimental evidence that humans with these disorders show distinct alterations in plasticity and metaplasticity, consistent with the findings in animal models. If confirmed in larger test-retest studies, repeated TMS measures of plasticity and metaplasticity may provide a valuable physiologic phenotype for ASD and FXS.
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Affiliation(s)
- Lindsay M. Oberman
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Fritz Ifert-Miller
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Umer Najib
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Shahid Bashir
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Joseph Gonzalez-Heydrich
- Department of Child and Adolescent Psychiatry, Boston Children's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Jonathan Picker
- Department of Child and Adolescent Psychiatry, Boston Children's Hospital, and Harvard Medical School, Boston, Massachusetts.,Division of Genetics, Boston Children's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Alexander Rotenberg
- Neuromodulation Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Institut Universitari Guttmann, Badalona, Barcelona, Spain
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12
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Cowley B, Kirjanen S, Partanen J, Castrén ML. Epileptic Electroencephalography Profile Associates with Attention Problems in Children with Fragile X Syndrome: Review and Case Series. Front Hum Neurosci 2016; 10:353. [PMID: 27462212 PMCID: PMC4941803 DOI: 10.3389/fnhum.2016.00353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 06/28/2016] [Indexed: 01/18/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and a variant of autism spectrum disorder (ASD). The FXS population is quite heterogeneous with respect to comorbidities, which implies the need for a personalized medicine approach, relying on biomarkers or endophenotypes to guide treatment. There is evidence that quantitative electroencephalography (EEG) endophenotype-guided treatments can support increased clinical benefit by considering the patient's neurophysiological profile. We describe a case series of 11 children diagnosed with FXS, aged one to 14 years, mean 4.6 years. Case data are based on longitudinal clinically-observed reports by attending physicians for comorbid symptoms including awake and asleep EEG profiles. We tabulate the comorbid EEG symptoms in this case series, and relate them to the literature on EEG endophenotypes and associated treatment options. The two most common endophenotypes in the data were diffuse slow oscillations and epileptiform EEG, which have been associated with attention and epilepsy respectively. This observation agrees with reported prevalence of comorbid behavioral symptoms for FXS. In this sample of FXS children, attention problems were found in 37% (4 of 11), and epileptic seizures in 45% (5 of 11). Attention problems were found to associate with the epilepsy endophenotype. From the synthesis of this case series and literature review, we argue that the evidence-based personalized treatment approach, exemplified by neurofeedback, could benefit FXS children by focusing on observable, specific characteristics of comorbid disease symptoms.
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Affiliation(s)
- Benjamin Cowley
- Brain Work Research Centre, Finnish Institute of Occupational HealthHelsinki, Finland; Cognitive Brain Research Unit, Cognitive Science, Institute of Behavioral Sciences, University of HelsinkiHelsinki, Finland
| | | | - Juhani Partanen
- Department of Clinical Neurophysiology, University Hospital of Helsinki Helsinki, Finland
| | - Maija L Castrén
- Faculty of Medicine, Physiology, University of HelsinkiHelsinki, Finland; Autism Foundation in FinlandHelsinki, Finland
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13
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Abu-Akel AM, Wood SJ, Hansen PC, Apperly IA. Perspective-taking abilities in the balance between autism tendencies and psychosis proneness. Proc Biol Sci 2016; 282:20150563. [PMID: 25972469 DOI: 10.1098/rspb.2015.0563] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Difficulties with the ability to appreciate the perspective of others (mentalizing) is central to both autism and schizophrenia spectrum disorders. While the disorders are diagnostically independent, they can co-occur in the same individual. The effect of such co-morbidity is hypothesized to worsen mentalizing abilities. The recent influential 'diametric brain theory', however, suggests that the disorders are etiologically and phenotypically diametrical, predicting opposing effects on one's mentalizing abilities. To test these contrasting hypotheses, we evaluated the effect of psychosis and autism tendencies on the perspective-taking (PT) abilities of 201 neurotypical adults, on the assumption that autism tendencies and psychosis proneness are heritable dimensions of normal variation. We show that while both autism tendencies and psychosis proneness induce PT errors, their interaction reduced these errors. Our study is, to our knowledge, the first to observe that co-occurring autistic and psychotic traits can exert opposing influences on performance, producing a normalizing effect possibly by way of their diametrical effects on socio-cognitive abilities. This advances the notion that some individuals may, to some extent, be buffered against developing either illness or present fewer symptoms owing to a balanced expression of autistic and psychosis liability.
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Affiliation(s)
- Ahmad M Abu-Akel
- School of Psychology, University of Birmingham, Edgbaston B15 2TT, UK
| | - Stephen J Wood
- School of Psychology, University of Birmingham, Edgbaston B15 2TT, UK Melbourne Neuropsychiatry Centre, University of Melbourne and Melbourne Health, Melbourne, Victoria, Australia
| | - Peter C Hansen
- School of Psychology, University of Birmingham, Edgbaston B15 2TT, UK
| | - Ian A Apperly
- School of Psychology, University of Birmingham, Edgbaston B15 2TT, UK
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14
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Uzunova G, Pallanti S, Hollander E. Excitatory/inhibitory imbalance in autism spectrum disorders: Implications for interventions and therapeutics. World J Biol Psychiatry 2016; 17:174-86. [PMID: 26469219 DOI: 10.3109/15622975.2015.1085597] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVES Imbalance between excitation and inhibition and increased excitatory-inhibitory (E-I) ratio is a common mechanism in autism spectrum disorders (ASD) that is responsible for the learning and memory, cognitive, sensory, motor deficits, and seizures occurring in these disorders. ASD are very heterogeneous and better understanding of E-I imbalance in brain will lead to better diagnosis and treatments. METHODS We perform a critical literature review of the causes and presentations of E-I imbalance in ASD. RESULTS E-I imbalance in ASD is due primarily to abnormal glutamatergic and GABAergic neurotransmission in key brain regions such as neocortex, hippocampus, amygdala, and cerebellum. Other causes are due to dysfunction of neuropeptides (oxytocin), synaptic proteins (neuroligins), and immune system molecules (cytokines). At the neuropathological level E-I imbalance in ASD is presented as a "minicolumnopathy". E-I imbalance alters the manner by which the brain processes information and regulates behaviour. New developments for investigating E-I imbalance such as optogenetics and transcranial magnetic stimulation (TMS) are presented. Non-invasive brain stimulation methods such as TMS for treatment of the core symptoms of ASD are discussed. CONCLUSIONS Understanding E-I imbalance has important implications for developing better pharmacological and behavioural treatments for ASD, including TMS, new drugs, biomarkers and patient stratification.
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Affiliation(s)
- Genoveva Uzunova
- a Albert Einstein College of Medicine and Montefiore Medical Center , Bronx , NY , USA
| | - Stefano Pallanti
- a Albert Einstein College of Medicine and Montefiore Medical Center , Bronx , NY , USA.,b Psychiatry and Behavioural Sciences, UC Davis Health System , CA , USA.,c Department Psychiatry , University of Florence , Florence , Italy.,d Icahn School of Medicine at Mount Sinai , New York , NY , USA
| | - Eric Hollander
- a Albert Einstein College of Medicine and Montefiore Medical Center , Bronx , NY , USA
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15
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Abstract
Over 70 years since the first description of the disease, disrupted social behavior remains a core clinical feature of autistic spectrum disorder. The complex etiology of the disorder portends the need for a better understanding of the brain mechanisms that enable social behaviors, particularly those that are relevant to autism which is characterized by a failure to develop peer relationships, difficulty with emotional reciprocity and imitative play, and disrupted language and communication skills. Toward this end, the current review will examine recent progress that has been made toward understanding the neural mechanisms underlying consociate social attachments.
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Affiliation(s)
- Gül Dölen
- a Department of Neuroscience, Brain Science Institute, Wendy Klag Center for Autism and Developmental Disabilities , Johns Hopkins University , Baltimore , MD , USA
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16
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Oberman LM, Rotenberg A, Pascual-Leone A. Use of transcranial magnetic stimulation in autism spectrum disorders. J Autism Dev Disord 2015; 45:524-36. [PMID: 24127165 DOI: 10.1007/s10803-013-1960-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The clinical, social and financial burden of autism spectrum disorder (ASD) is staggering. We urgently need valid and reliable biomarkers for diagnosis and effective treatments targeting the often debilitating symptoms. Transcranial magnetic stimulation (TMS) is beginning to be used by a number of centers worldwide and may represent a novel technique with both diagnostic and therapeutic potential. Here we critically review the current scientific evidence for the use of TMS in ASD. Though preliminary data suggests promise, there is simply not enough evidence yet to conclusively support the clinical widespread use of TMS in ASD, neither diagnostically nor therapeutically. Carefully designed and properly controlled clinical trials are warranted to evaluate the true potential of TMS in ASD.
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Affiliation(s)
- Lindsay M Oberman
- Berenson-Allen Center for Noninvasive Brain Stimulation, and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, KS 158, Boston, MA, 02215, USA
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17
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Dölen G. Oxytocin: parallel processing in the social brain? J Neuroendocrinol 2015; 27:516-35. [PMID: 25912257 DOI: 10.1111/jne.12284] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 03/29/2015] [Accepted: 04/07/2015] [Indexed: 12/31/2022]
Abstract
Early studies attempting to disentangle the network complexity of the brain exploited the accessibility of sensory receptive fields to reveal circuits made up of synapses connected both in series and in parallel. More recently, extension of this organisational principle beyond the sensory systems has been made possible by the advent of modern molecular, viral and optogenetic approaches. Here, evidence supporting parallel processing of social behaviours mediated by oxytocin is reviewed. Understanding oxytocinergic signalling from this perspective has significant implications for the design of oxytocin-based therapeutic interventions aimed at disorders such as autism, where disrupted social function is a core clinical feature. Moreover, identification of opportunities for novel technology development will require a better appreciation of the complexity of the circuit-level organisation of the social brain.
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Affiliation(s)
- Gül Dölen
- Department of Neuroscience, Brain Science Institute, Wendy Klag Center for Developmental Disabilities and Autism, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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18
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Desarkar P, Rajji TK, Ameis SH, Daskalakis ZJ. Assessing and Stabilizing Aberrant Neuroplasticity in Autism Spectrum Disorder: The Potential Role of Transcranial Magnetic Stimulation. Front Psychiatry 2015; 6:124. [PMID: 26441685 PMCID: PMC4563147 DOI: 10.3389/fpsyt.2015.00124] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/25/2015] [Indexed: 11/13/2022] Open
Abstract
Exciting developments have taken place in the neuroscience research in autism spectrum disorder (ASD), and results from these studies indicate that brain in ASD is associated with aberrant neuroplasticity. Transcranial magnetic stimulation (TMS) has rapidly evolved to become a widely used, safe, and non-invasive neuroscientific tool to investigate a variety of neurophysiological processes, including neuroplasticity. The diagnostic and therapeutic potential of TMS in ASD is beginning to be realized. In this article, we briefly reviewed evidence of aberrant neuroplasticity in ASD, suggested future directions in assessing neuroplasticity using repetitive TMS (rTMS), and discussed the potential of rTMS in rectifying aberrant neuroplasticity in ASD.
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Affiliation(s)
- Pushpal Desarkar
- Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada ; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health , Toronto, ON , Canada
| | - Tarek K Rajji
- Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada ; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health , Toronto, ON , Canada
| | - Stephanie H Ameis
- Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada ; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health , Toronto, ON , Canada ; Department of Psychiatry, The Hospital for Sick Children, University of Toronto , Toronto, ON , Canada ; Research Imaging Centre, Campbell Family Mental Health Research Institute, The Centre for Addiction and Mental Health (CAMH) , Toronto, ON , Canada
| | - Zafiris Jeff Daskalakis
- Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada ; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health , Toronto, ON , Canada
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19
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Effect of anodal transcranial direct current stimulation on autism: a randomized double-blind crossover trial. Behav Neurol 2014; 2014:173073. [PMID: 25530675 PMCID: PMC4230001 DOI: 10.1155/2014/173073] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 08/12/2014] [Accepted: 08/12/2014] [Indexed: 12/21/2022] Open
Abstract
The aim of this study was to evaluate the Childhood Autism Rating Scale (CARS), Autism Treatment Evaluation Checklist (ATEC), and Children's Global Assessment Scale (CGAS) after anodal transcranial direct current stimulation (tDCS) in individuals with autism. Twenty patients with autism received 5 consecutive days of both sham and active tDCS stimulation (1 mA) in a randomized double-blind crossover trial over the left dorsolateral prefrontal cortex (F3) for 20 minutes in different orders. Measures of CARS, ATEC, and CGAS were administered before treatment and at 7 days posttreatment. The result showed statistical decrease in CARS score (P < 0.001). ATEC total was decreased from 67.25 to 58 (P < 0.001). CGAS was increased at 7 days posttreatment (P = 0.042). Our study suggests that anodal tDCS over the F3 may be a useful clinical tool in autism.
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20
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Oberman L, Pascual-Leone A. Changes in plasticity across the lifespan: cause of disease and target for intervention. PROGRESS IN BRAIN RESEARCH 2014; 207:91-120. [PMID: 24309252 DOI: 10.1016/b978-0-444-63327-9.00016-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We conceptualize brain plasticity as an intrinsic property of the nervous system enabling rapid adaptation in response to changes in an organism's internal and external environment. In prenatal and early postnatal development, plasticity allows for the formation of organized nervous system circuitry and the establishment of functional networks. As the individual is exposed to various sensory stimuli in the environment, brain plasticity allows for functional and structural adaptation and underlies learning and memory. We argue that the mechanisms of plasticity change over the lifespan with different slopes of change in different individuals. These changes play a key role in the clinical phenotype of neurodevelopmental disorders like autism and schizophrenia and neurodegenerative disorders such as Alzheimer's disease. Altered plasticity not only can trigger maladaptive cascades and can be the cause of deficits and disability but also offers opportunities for novel therapeutic interventions. In this chapter, we discuss the importance of brain plasticity across the lifespan and how neuroplasticity-based therapies offer promise for disorders with otherwise limited effective treatment.
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Affiliation(s)
- Lindsay Oberman
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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21
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Rossignol R, Ranchon-Cole I, Pâris A, Herzine A, Perche A, Laurenceau D, Bertrand P, Cercy C, Pichon J, Mortaud S, Briault S, Menuet A, Perche O. Visual sensorial impairments in neurodevelopmental disorders: evidence for a retinal phenotype in Fragile X Syndrome. PLoS One 2014; 9:e105996. [PMID: 25153086 PMCID: PMC4143372 DOI: 10.1371/journal.pone.0105996] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/25/2014] [Indexed: 01/28/2023] Open
Abstract
Visual sensory impairments are common in Mental Deficiency (MD) and Autism Spectrum Disorder (ASD). These defects are linked to cerebral dysfunction in the visual cortical area characterized by the deregulation of axon growth/guidance and dendrite spine immaturity of neurons. However, visual perception had not been addressed, although the retina is part of the central nervous system with a common embryonic origin. Therefore, we investigated retinal perception, the first event of vision, in a murine model of MD with autistic features. We document that retinal function is altered in Fmr1 KO mice, a model of human Fragile X Syndrome. Indeed, In Fmr1 KO mice had a lower retinal function characterized by a decreased photoreceptors neuron response, due to a 40% decrease in Rhodopsin content and to Rod Outer Segment destabilization. In addition, we observed an alteration of the visual signal transmission between photoreceptors and the inner retina which could be attributed to deregulations of pre- and post- synaptic proteins resulting in retinal neurons synaptic destabilization and to retinal neurons immaturity. Thus, for the first time, we demonstrated that retinal perception is altered in a murine model of MD with autistic features and that there are strong similarities between cerebral and retinal cellular and molecular defects. Our results suggest that both visual perception and integration must be taken into account in assessing visual sensory impairments in MD and ASD.
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Affiliation(s)
- Rafaëlle Rossignol
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Isabelle Ranchon-Cole
- Laboratory of Sensorial Biophysical, University of Clermont 1, Clermont-Ferrand, France
| | - Arnaud Pâris
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Ameziane Herzine
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Astrid Perche
- Genetic Department, Regional Hospital, Orléans, France
| | | | - Pauline Bertrand
- Laboratory of Sensorial Biophysical, University of Clermont 1, Clermont-Ferrand, France
| | - Christine Cercy
- Laboratory of Sensorial Biophysical, University of Clermont 1, Clermont-Ferrand, France
| | - Jacques Pichon
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Stéphane Mortaud
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Sylvain Briault
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
- Genetic Department, Regional Hospital, Orléans, France
| | - Arnaud Menuet
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
| | - Olivier Perche
- UMR7355, CNRS, Orléans, France
- Experimental and Molecular Immunology and Neurogenetics, University of Orléans, Orléans, France
- Genetic Department, Regional Hospital, Orléans, France
- * E-mail:
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22
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Hyperplasticity in Autism Spectrum Disorder confers protection from Alzheimer's disease. Med Hypotheses 2014; 83:337-42. [PMID: 25047996 DOI: 10.1016/j.mehy.2014.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 06/03/2014] [Accepted: 06/09/2014] [Indexed: 11/22/2022]
Abstract
Autism Spectrum Disorders (ASD) currently affects approximately 1% of the population causing grave disability and necessitating a better understanding of the currently enigmatic etiology of these disorders. Recent data suggest that some patients with ASD may have a dysfunction in brain plasticity (specifically data from animal models and human studies suggest a propensity toward excessive amount of plasticity). Plasticity is essential to the establishment and maintenance of brain circuitry; however, too much plasticity may lead to instability of structural connections and compromise of functional systems necessary for cognition and behavior. Multiple lines of evidence suggest that plasticity declines throughout the age-span and may underlie age-related cognitive decline. We hypothesize that individuals whose cortex begins as relatively "hyperplastic" (such as may be seen in ASD) should then be relatively protected from age-related cognitive decline (which we suggest is related to a reduction in plasticity). In the current study, we conducted a multiple linear regression using age and diagnosis as predictor variables in order to evaluate strength of the relationship between age, diagnosis or an interaction of the two factors and the degree of modulation in cortical excitability by transcranial magnetic stimulation as an index of cortical plasticity. Results indicate that across the age-span individuals with ASD show a consistently increased modulation of cortical excitability as compared to typically developing individuals, such that the general slope of decline across the age span is matched across both groups. We have argued that an individual's risk of age-related cognitive decline (and risk for manifesting symptoms of dementia) depends on the individual's starting point and slopes of change in plasticity efficiency over the lifespan. Therefore, our results suggest that individuals with ASD might be relatively protected from age-related cognitive decline and the risk of dementia.
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Uutela M, Lindholm J, Rantamäki T, Umemori J, Hunter K, Võikar V, Castrén ML. Distinctive behavioral and cellular responses to fluoxetine in the mouse model for Fragile X syndrome. Front Cell Neurosci 2014; 8:150. [PMID: 24904293 PMCID: PMC4036306 DOI: 10.3389/fncel.2014.00150] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/09/2014] [Indexed: 11/13/2022] Open
Abstract
Fluoxetine is used as a therapeutic agent for autism spectrum disorder (ASD), including Fragile X syndrome (FXS). The treatment often associates with disruptive behaviors such as agitation and disinhibited behaviors in FXS. To identify mechanisms that increase the risk to poor treatment outcome, we investigated the behavioral and cellular effects of fluoxetine on adult Fmr1 knockout (KO) mice, a mouse model for FXS. We found that fluoxetine reduced anxiety-like behavior of both wild-type and Fmr1 KO mice seen as shortened latency to enter the center area in the open field test. In Fmr1 KO mice, fluoxetine normalized locomotor hyperactivity but abnormally increased exploratory activity. Reduced brain-derived neurotrophic factor (BDNF) and increased TrkB receptor expression levels in the hippocampus of Fmr1 KO mice associated with inappropriate coping responses under stressful condition and abolished antidepressant activity of fluoxetine. Fluoxetine response in the cell proliferation was also missing in the hippocampus of Fmr1 KO mice when compared with wild-type controls. The postnatal mRNA expression of serotonin transporter (SERT) was reduced in the thalamic nuclei of Fmr1 KO mice during the time of transient innervation of somatosensory neurons suggesting that developmental changes of SERT expression were involved in the differential cellular and behavioral responses to fluoxetine in wild-type and Fmr1 mice. The results indicate that changes of BDNF/TrkB signaling contribute to differential behavioral responses to fluoxetine among individuals with ASD.
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Affiliation(s)
- Marko Uutela
- Institute of Biomedicine/Physiology, University of Helsinki Helsinki, Finland
| | - Jesse Lindholm
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | - Tomi Rantamäki
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | - Juzoh Umemori
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | - Kerri Hunter
- Institute of Biomedicine/Physiology, University of Helsinki Helsinki, Finland
| | - Vootele Võikar
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | - Maija L Castrén
- Institute of Biomedicine/Physiology, University of Helsinki Helsinki, Finland ; Department of Child Neurology, Hospital for Children and Adolescents, University Hospital of Helsinki Helsinki, Finland
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24
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Petrinovic MM, Künnecke B. Neuroimaging endophenotypes in animal models of autism spectrum disorders: lost or found in translation? Psychopharmacology (Berl) 2014; 231:1167-89. [PMID: 23852013 DOI: 10.1007/s00213-013-3200-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/26/2013] [Indexed: 11/26/2022]
Abstract
RATIONALE Autism spectrum disorder(s) (ASDs) is a neurodevelopmental disorder characterized by stereotyped behaviours and impairments in communication and social interactions. This heterogeneity has been a major obstacle in uncovering the aetiology and biomarkers of ASDs. Rodent models with genetic modifications or environmental insults have been created to study particular endophenotypes and bridge the gap between genetics and behavioural phenotypes. Translational neuroimaging modalities with their ability to screen the brain noninvasively and yield structural, biochemical and functional information provide a unique platform for discovery and evaluation of such endophenotypes in preclinical and clinical research. OBJECTIVES We reviewed literature on translational neuroimaging in rodent models of ASDs. The most prominent models will be described and the respective neuroimaging endophenotypes will be discussed with reference to human data. A perspective on future directions of translational neuroimaging in animal models of ASDs will be given. RESULTS AND CONCLUSIONS To date, we experience a proliferation of rodent models which recapitulate specific liabilities identified in ASDs patients. Translational neuroimaging in these models is emerging but is skewed towards magnetic resonance imaging (MRI) modalities. Volumetric and structural assessments of the brain are dominating and a host of endophenotypes have been reported that allude to findings in ASDs patients but with only few to converge among the models. Caveats of current studies are the diverging biological conditions related to genetic background and age of the animals. It is anticipated that longitudinal and functional assessments will gain much importance and will help elucidating mechanistic relationship between behavioural and structural endophenotypes.
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Affiliation(s)
- Marija M Petrinovic
- F. Hoffmann-La Roche AG, pRED, Pharma Research and Early Development, DTA Neuroscience, Building 68, Room 327A, Grenzacherstrasse 124, 4070, Basel, Switzerland
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25
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Reduced subcortical glutamate/glutamine in adults with autism spectrum disorders: a [¹H]MRS study. Transl Psychiatry 2013; 3:e279. [PMID: 23838890 PMCID: PMC3731785 DOI: 10.1038/tp.2013.53] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 04/20/2013] [Accepted: 04/25/2013] [Indexed: 01/13/2023] Open
Abstract
Dysfunctional glutamatergic neurotransmission has been implicated in autism spectrum disorder (ASD). However, relatively few studies have directly measured brain glutamate in ASD adults, or related variation in glutamate to clinical phenotype. We therefore set out to investigate brain glutamate levels in adults with an ASD, comparing these to healthy controls and also comparing results between individuals at different points on the spectrum of symptom severity. We recruited 28 adults with ASD and 14 matched healthy controls. Of those with ASD, 15 fulfilled the 'narrowly' defined criteria for typical autism, whereas 13 met the 'broader phenotype'. We measured the concentration of the combined glutamate and glutamine signal (Glx), and other important metabolites, using proton magnetic resonance spectroscopy in two brain regions implicated in ASD--the basal ganglia (including the head of caudate and the anterior putamen) and the dorsolateral prefrontal cortex--as well as in a parietal cortex 'control' region. Individuals with ASD had a significant decrease (P<0.001) in concentration of Glx in the basal ganglia, and this was true in both the 'narrow' and 'broader' phenotype. Also, within the ASD sample, reduced basal ganglia Glx was significantly correlated with increased impairment in social communication (P=0.013). In addition, there was a significant reduction in the concentration of other metabolites such as choline, creatine (Cr) and N-acetylaspartate (NAA) in the basal ganglia. In the dorsolateral prefrontal cortex, Cr and NAA were reduced (P<0.05), although Glx was not. There were no detectable differences in Glx, or any other metabolite, in the parietal lobe control region. There were no significant between-group differences in age, gender, IQ, voxel composition or data quality. In conclusion, individuals across the spectrum of ASD have regionally specific abnormalities in subcortical glutamatergic neurotransmission that are associated with variation in social development.
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26
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Perkins EA, Berkman KA. Into the unknown: aging with autism spectrum disorders. AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2012; 117:478-496. [PMID: 23167487 DOI: 10.1352/1944-7558-117.6.478] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Research investigation of older adults with autism spectrum disorders (ASD) noticeably lags behind studies of children and younger adults with ASD. This article reviews the current literature regarding a range of quality of life outcomes of aging adults with ASD. Studies that have addressed life expectancy, comorbid physical and mental health issues, ASD symptomatology, and social, residential, and vocational outcomes are reviewed. Research challenges in identifying older cohorts of adults with ASD are also discussed, and notable areas of concern are highlighted. Overall, aging with ASD does present challenges, but there is also evidence that positive outcomes are attainable. The article concludes with brief recommendations on how to optimize the aging process for individuals with ASD.
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27
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Oberman LM. mGluR antagonists and GABA agonists as novel pharmacological agents for the treatment of autism spectrum disorders. Expert Opin Investig Drugs 2012; 21:1819-25. [PMID: 23013434 DOI: 10.1517/13543784.2012.729819] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The CDC currently estimates the prevalence of autism spectrum disorders (ASD) at 1 in 88 children. Though the exact etiology of ASD is unknown, recent studies implicate synaptic maturation and plasticity in the pathogenesis of ASD leading to an imbalance of excitation and inhibition, and specifically a disproportionately high level of excitation. Pharmacological agents that modulate excitation and inhibition are currently in clinical trials for treatment of ASD and show promising preliminary results. AREAS COVERED This paper reviews the literature implicating the role of glutamate and GABA pathways in the pathophysiology of ASD. It also provides a review of the current results from both animal models and human clinical trials of drugs aimed at normalizing the imbalance of excitation and inhibition through the use of metabotropic glutamate receptor (mGluR) antagonists and GABA agonists. EXPERT OPINION Both mGluR antagonists and GABA agonists have promising preliminary data from animal model and small-scale Phase II human trials. They show significant efficacy in subpopulations and appear to have favorable side-effect profiles. Though preliminary data are extremely promising, results from ongoing larger, double-blind, placebo-controlled studies will give a more complete understanding of the efficacy and side-effect profile related to these drugs.
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Affiliation(s)
- Lindsay M Oberman
- Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, KS 158, Boston, MA 02215, USA.
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28
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mGluR5 knockout mice display increased dendritic spine densities. Neurosci Lett 2012; 524:65-8. [PMID: 22819970 DOI: 10.1016/j.neulet.2012.07.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/25/2012] [Accepted: 07/10/2012] [Indexed: 12/24/2022]
Abstract
Alterations in dendritic spine densities and morphologies have been correlated with the abnormal functioning of the synapse. Specifically the metabotropic glutamate receptor 5 (mGluR5) has been implicated in dendrogenesis and spineogenesis, since its activation triggers various signaling cascades that have been demonstrated to play roles in synaptic maturation and plasticity. Here we used the Golgi impregnation technique to analyze the dendritic spines of mGluR5(-/-) knockout mice in comparison to their heterozygote mGluR5(+/-) littermates. mGluR5(-/-) mice had elevated spine densities irrespective of spine type or location along their dendritic trees in comparison to mGluR5(+/-) animals. Such anatomical changes may underlie the hyperexcitability observed in mGluR5 total knockout mice.
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29
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Oberman L, Eldaief M, Fecteau S, Ifert-Miller F, Tormos JM, Pascual-Leone A. Abnormal modulation of corticospinal excitability in adults with Asperger's syndrome. Eur J Neurosci 2012; 36:2782-8. [PMID: 22738084 DOI: 10.1111/j.1460-9568.2012.08172.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Most candidate genes and genetic abnormalities linked to autism spectrum disorders (ASD) are thought to play a role in developmental and experience-dependent plasticity. As a possible index of plasticity, we assessed the modulation of motor corticospinal excitability in individuals with Asperger's syndrome (AS) using transcranial magnetic stimulation (TMS). We measured the modulatory effects of theta-burst stimulation (TBS) on motor evoked potentials (MEPs) induced by single-pulse TMS in individuals with AS as compared with age-, gender- and IQ-matched neurotypical controls. The effect of TBS lasted significantly longer in the AS group. The duration of the TBS-induced modulation alone enabled the reliable classification of a second study cohort of subjects as AS or neurotypical. The alteration in the modulation of corticospinal excitability in AS is thought to reflect aberrant mechanisms of plasticity, and might provide a valuable future diagnostic biomarker for the disease and ultimately offer a target for novel therapeutic interventions.
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Affiliation(s)
- Lindsay Oberman
- Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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30
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Gladding CM, Fitzjohn SM, Molnár E. Metabotropic glutamate receptor-mediated long-term depression: molecular mechanisms. Pharmacol Rev 2009; 61:395-412. [PMID: 19926678 DOI: 10.1124/pr.109.001735] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to modify synaptic transmission between neurons is a fundamental process of the nervous system that is involved in development, learning, and disease. Thus, synaptic plasticity is the ability to bidirectionally modify transmission, where long-term potentiation and long-term depression (LTD) represent the best characterized forms of plasticity. In the hippocampus, two main forms of LTD coexist that are mediated by activation of either N-methyl-d-aspartic acid receptors (NMDARs) or metabotropic glutamate receptors (mGluRs). Compared with NMDAR-LTD, mGluR-LTD is less well understood, but recent advances have started to delineate the underlying mechanisms. mGluR-LTD at CA3:CA1 synapses in the hippocampus can be induced either by synaptic stimulation or by bath application of the group I selective agonist (R,S)-3,5-dihydroxyphenylglycine. Multiple signaling mechanisms have been implicated in mGluR-LTD, illustrating the complexity of this form of plasticity. This review provides an overview of recent studies investigating the molecular mechanisms underlying hippocampal mGluR-LTD. It highlights the role of key molecular components and signaling pathways that are involved in the induction and expression of mGluR-LTD and considers how the different signaling pathways may work together to elicit a persistent reduction in synaptic transmission.
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Affiliation(s)
- Clare M Gladding
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
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