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Cording KR, Bateup HS. Altered motor learning and coordination in mouse models of autism spectrum disorder. Front Cell Neurosci 2023; 17:1270489. [PMID: 38026686 PMCID: PMC10663323 DOI: 10.3389/fncel.2023.1270489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 12/01/2023] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing prevalence. Over 1,000 risk genes have now been implicated in ASD, suggesting diverse etiology. However, the diagnostic criteria for the disorder still comprise two major behavioral domains - deficits in social communication and interaction, and the presence of restricted and repetitive patterns of behavior (RRBs). The RRBs associated with ASD include both stereotyped repetitive movements and other motor manifestations including changes in gait, balance, coordination, and motor skill learning. In recent years, the striatum, the primary input center of the basal ganglia, has been implicated in these ASD-associated motor behaviors, due to the striatum's role in action selection, motor learning, and habit formation. Numerous mouse models with mutations in ASD risk genes have been developed and shown to have alterations in ASD-relevant behaviors. One commonly used assay, the accelerating rotarod, allows for assessment of both basic motor coordination and motor skill learning. In this corticostriatal-dependent task, mice walk on a rotating rod that gradually increases in speed. In the extended version of this task, mice engage striatal-dependent learning mechanisms to optimize their motor routine and stay on the rod for longer periods. This review summarizes the findings of studies examining rotarod performance across a range of ASD mouse models, and the resulting implications for the involvement of striatal circuits in ASD-related motor behaviors. While performance in this task is not uniform across mouse models, there is a cohort of models that show increased rotarod performance. A growing number of studies suggest that this increased propensity to learn a fixed motor routine may reflect a common enhancement of corticostriatal drive across a subset of mice with mutations in ASD-risk genes.
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Affiliation(s)
- Katherine R. Cording
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
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2
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Lee B, Beuhler L, Lee HY. The Primary Ciliary Deficits in Cerebellar Bergmann Glia of the Mouse Model of Fragile X Syndrome. CEREBELLUM (LONDON, ENGLAND) 2022; 21:801-813. [PMID: 35438410 PMCID: PMC10857775 DOI: 10.1007/s12311-022-01382-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/07/2022] [Indexed: 12/14/2022]
Abstract
Primary cilia are non-motile cilia that function as antennae for cells to sense signals. Deficits of primary cilia cause ciliopathies, leading to the pathogenesis of various developmental disorders; however, the contribution of primary cilia to neurodevelopmental disorders is largely unknown. Fragile X syndrome (FXS) is a genetically inherited disorder and is the most common known cause of autism spectrum disorders. FXS is caused by the silencing of the fragile X mental retardation 1 (FMR1) gene, which encodes for the fragile X mental retardation protein (FMRP). Here, we discovered a reduction in the number of primary cilia and the Sonic hedgehog (Shh) signaling in cerebellar Bergmann glia of Fmr1 KO mice. We further found reduced granule neuron precursor (GNP) proliferation and thickness of the external germinal layer (EGL) in Fmr1 KO mice, implicating that primary ciliary deficits in Bergmann glia may contribute to cerebellar developmental phenotypes in FXS, as Shh signaling through primary cilia in Bergmann glia is known to mediate proper GNP proliferation in the EGL. Taken together, our study demonstrates that FMRP loss leads to primary ciliary deficits in cerebellar Bergmann glia which may contribute to cerebellar deficits in FXS.
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Affiliation(s)
- Bumwhee Lee
- The Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Laura Beuhler
- The Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Hye Young Lee
- The Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
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3
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Perez-Fernandez C, Matamala Montoya M, Morales-Navas M, Guardia-Escote L, Cabré M, Colomina MT, Giménez E, Sánchez-Santed F. Influence of Gestational Chlorpyrifos Exposure on ASD-like Behaviors in an fmr1-KO Rat Model. Mol Neurobiol 2022; 59:5835-5855. [PMID: 35802248 DOI: 10.1007/s12035-022-02933-0] [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: 03/07/2022] [Accepted: 06/17/2022] [Indexed: 11/26/2022]
Abstract
Based on previous reports, exposure to pesticides could be linked to the prevalence increase of autism spectrum disorders (ASD). Gestational exposure to chlorpyrifos (CPF) has been associated with ASD diagnosis in humans and ASD-like behaviors in rodents. However, ASD severity degree results from the complex relationship between genetic background and environmental factors. Thus, animals with a genetic vulnerability and prenatally exposed to CPF could have a more severe ASD-like phenotype. Fragile X syndrome is one of the most common monogenic causes of ASD, characterized by a mutation in the X chromosome which alters the expression of the fragile X mental retardation protein (FMRP). Based on this, some fmr1 knockout (KO) rodent models have been developed to study the physiological and genetic basis of ASD. Both fmr1-KO and wild-type male rats (F2 generation) were used in the present study. F1 pregnant females were randomly exposed to 1 mg/kg/mL/day of CPF (s.c.) from GD12.5-15.5 or vehicle. Different behavioral, developmental, and molecular variables were analyzed in F2 males. KO rats were heavier, emitted altered USVs, were socially inefficient, reacted more to a novel stimulus, were hyperactive when exploring a new context, but hypoactive when exploring anxiety-inducing environments, and had an upregulated hippocampal expression of the grin2c gene. When exposed to low doses of CPF during gestation, these KO rats showed decreased climbing capacity, dysfunctional social interaction, and increased hippocampal expression for kcc1 and 5ht2c genes. Gestational CPF exposure increased the ASD-like phenotype in those animals with a genetic vulnerability, although its effect was less generalized than expected. It is the first time that this additive effect of CPF exposure and the fmr1-KO genetic vulnerability model is explored concerning social traits or any other behavior.
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Affiliation(s)
- Cristian Perez-Fernandez
- Department of Psychology and Health Research Center (CEINSA), Laboratory of Psychobiology, University of Almería CeiA3, Carretera de Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain
| | - María Matamala Montoya
- Biomolecular Mass Spectrometry and Proteomics Group, Faculty of Science, Utrecht University, 3584 CS, Utrecht, The Netherlands
| | - Miguel Morales-Navas
- Department of Psychology and Health Research Center (CEINSA), Laboratory of Psychobiology, University of Almería CeiA3, Carretera de Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain
| | - Laia Guardia-Escote
- Research in Neurobehavior and Health (NEUROLAB), Universitat Rovira I Virgili, 43007, Tarragona, Spain
- Department of Psychology and Research Center for Behavior Assessment (CRAMC), Universitat Rovira I Virgili, Campus Sescelades, 43007, Tarragona, Spain
| | - María Cabré
- Research in Neurobehavior and Health (NEUROLAB), Universitat Rovira I Virgili, 43007, Tarragona, Spain
- Department of Biochemistry and Biotechnology, Universitat Rovira I Virgili, 43007, Tarragona, Spain
| | - María Teresa Colomina
- Research in Neurobehavior and Health (NEUROLAB), Universitat Rovira I Virgili, 43007, Tarragona, Spain
- Department of Psychology and Research Center for Behavior Assessment (CRAMC), Universitat Rovira I Virgili, Campus Sescelades, 43007, Tarragona, Spain
| | - Estela Giménez
- Department of Biology and Geology, University of Almería, Ctra. Sacramento, s/n, 04120, Almería, Spain
| | - Fernando Sánchez-Santed
- Department of Psychology and Health Research Center (CEINSA), Laboratory of Psychobiology, University of Almería CeiA3, Carretera de Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain.
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Scott EY, Woolard KD, Finno CJ, Murray JD. Cerebellar Abiotrophy Across Domestic Species. THE CEREBELLUM 2019; 17:372-379. [PMID: 29294214 DOI: 10.1007/s12311-017-0914-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cerebellar abiotrophy (CA) is a neurodegenerative disorder affecting the cerebellum and occurs in multiple species. Although CA is well researched in humans and mice, domestic species such as the dog, cat, sheep, cow, and horse receive little recognition. This may be due to few studies addressing the mechanism of CA in these species. However, valuable information can still be extracted from these cases. A review of the clinicohistologic phenotype of CA in these species and determining the various etiologies of CA may aid in determining conserved and required pathways necessary for proper cerebellar development and function. This review outlines research approaches of studies of CA in domestic species, compared to the approaches used in mice, with the objective of comparing CA in domestic species while identifying areas for further research efforts.
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Affiliation(s)
- Erica Yuki Scott
- Department of Animal Science, University of California, Davis, Meyer Hall, 1 Shields Ave, Davis, CA, 95616, USA
| | - Kevin Douglas Woolard
- Department of Pathology, Microbiology & Immunology, University of California, Davis, Davis, CA, USA
| | - Carrie J Finno
- Department of Population Health and Reproduction, University of California, Davis, Davis, CA, USA
| | - James D Murray
- Department of Animal Science, University of California, Davis, Meyer Hall, 1 Shields Ave, Davis, CA, 95616, USA.
- Department of Population Health and Reproduction, University of California, Davis, Davis, CA, USA.
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Bachmann SO, Sledziowska M, Cross E, Kalbassi S, Waldron S, Chen F, Ranson A, Baudouin SJ. Behavioral training rescues motor deficits in Cyfip1 haploinsufficiency mouse model of autism spectrum disorders. Transl Psychiatry 2019; 9:29. [PMID: 30664619 PMCID: PMC6341103 DOI: 10.1038/s41398-018-0338-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/15/2018] [Accepted: 11/25/2018] [Indexed: 12/27/2022] Open
Abstract
Deletions in the 15q11.2 region of the human genome are associated with neurobehavioral deficits, and motor development delay, as well as in some cases, symptoms of autism or schizophrenia. The cytoplasmic FMRP-interacting protein 1 (CYFIP1) is one of the four genes contained within this locus and has been associated with other genetic forms of autism spectrum disorders (ASD). In mice, Cyfip1 haploinsufficiency leads to alteration of dendritic spine morphology and defects in synaptic plasticity, two pathophysiological hallmarks of mouse models of ASD. At the behavioral level, however, Cyfip1 haploinsufficiency leads to minor phenotypes, not directly relevant for 15q11.2 deletion syndrome or ASD. A fundamental question is whether neuronal phenotypes caused by the mutation of Cyfip1 are relevant for the human condition. Here, we describe a synaptic cluster of ASD-associated proteins centered on CYFIP1 and the adhesion protein Neuroligin-3. Cyfip1 haploinsufficiency in mice led to decreased dendritic spine density and stability associated with social behavior and motor learning phenotypes. Behavioral training early in development resulted in alleviating the motor learning deficits caused by Cyfip1 haploinsufficiency. Altogether, these data provide new insight into the neuronal and behavioral phenotypes caused by Cyfip1 mutation and proof-of-concept for the development of a behavioral therapy to treat phenotypes associated with 15q11.2 syndromes and ASD.
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Affiliation(s)
- Sven O. Bachmann
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
| | - Monika Sledziowska
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
| | - Ellen Cross
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
| | - Shireene Kalbassi
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
| | - Sophie Waldron
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
| | - Fangli Chen
- 0000 0001 0807 5670grid.5600.3Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, CF24 4HQ UK
| | - Adam Ranson
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK. .,Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Stéphane J. Baudouin
- 0000 0001 0807 5670grid.5600.3School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales UK
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Bruchhage MMK, Bucci MP, Becker EBE. Cerebellar involvement in autism and ADHD. HANDBOOK OF CLINICAL NEUROLOGY 2018; 155:61-72. [PMID: 29891077 DOI: 10.1016/b978-0-444-64189-2.00004-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The cerebellum has long been known for its importance in motor learning and coordination. However, increasing evidence supports a role for the cerebellum in cognition and emotion. Consistent with a role in cognitive functions, the cerebellum has emerged as one of the key brain regions affected in nonmotor disorders, including autism spectrum disorder and attention deficit-hyperactivity disorder. Here, we discuss behavioral, postmortem, genetic, and neuroimaging studies in humans in order to understand the cerebellar contributions to the pathogenesis of both disorders. We also review relevant animal model findings.
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Affiliation(s)
- Muriel M K Bruchhage
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Maria-Pia Bucci
- Child and Adolescent Psychiatry Department, Robert Debré Hospital, Paris, France
| | - Esther B E Becker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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7
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Bonasera SJ, Chaudoin TR, Goulding EH, Mittek M, Dunaevsky A. Decreased home cage movement and oromotor impairments in adult Fmr1-KO mice. GENES BRAIN AND BEHAVIOR 2017; 16:564-573. [PMID: 28218824 DOI: 10.1111/gbb.12374] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 01/16/2017] [Accepted: 02/15/2017] [Indexed: 01/15/2023]
Abstract
Fragile X syndrome (FXS) is a common inherited disorder that significantly impacts family and patient day-to-day living across the entire life span. The childhood and adolescent behavioral consequences of FXS are well appreciated. However, there are significantly fewer studies (except those examining psychiatric comorbidities) assessing behavioral phenotypes seen in adults with FXS. Mice engineered with a genetic lesion of fragile X mental retardation 1 (Fmr1) recapitulate important molecular and neuroanatomical characteristics of FXS, and provide a means to evaluate adult behavioral phenotypes associated with FXS. We give the first description of baseline behaviors including feeding, drinking, movement and their circadian rhythms; all observed over 16 consecutive days following extensive environmental habituation in adult Fmr1-KO mutant mice. We find no genotypic changes in mouse food ingestion, feeding patterns, metabolism or circadian patterns of movement, feeding and drinking. After habituation, Fmr1-KO mice show significantly less daily movement during their active phase (the dark cycle). However, Fmr1-KO mice have more bouts of activity during the light cycle compared with wild types. In addition, Fmr1-KO mice show significantly less daily water ingestion during the circadian dark cycle, and this reduction in water intake is accompanied by a decrease in the amount of water ingested per lick. The observed water ingestion and circadian phenotypes noted in Fmr1-KO mice recapitulate known clinical aspects previously described in FXS. The finding of decreased movement in Fmr1-KO mice is novel, and suggests a dissociation between baseline and novelty-evoked activity for Fmr1-KO mice.
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Affiliation(s)
- S J Bonasera
- Division of Geriatrics, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE
| | - T R Chaudoin
- Division of Geriatrics, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE
| | - E H Goulding
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL
| | - M Mittek
- Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE
| | - A Dunaevsky
- Department of Developmental Neuroscience, Monroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE, USA
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Bausch AE, Dieter R, Nann Y, Hausmann M, Meyerdierks N, Kaczmarek LK, Ruth P, Lukowski R. The sodium-activated potassium channel Slack is required for optimal cognitive flexibility in mice. ACTA ACUST UNITED AC 2015; 22:323-35. [PMID: 26077685 PMCID: PMC4478330 DOI: 10.1101/lm.037820.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/05/2015] [Indexed: 01/14/2023]
Abstract
Kcnt1 encoded sodium-activated potassium channels (Slack channels) are highly expressed throughout the brain where they modulate the firing patterns and general excitability of many types of neurons. Increasing evidence suggests that Slack channels may be important for higher brain functions such as cognition and normal intellectual development. In particular, recent findings have shown that human Slack mutations produce very severe intellectual disability and that Slack channels interact directly with the Fragile X mental retardation protein (FMRP), a protein that when missing or mutated results in Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism in humans. We have now analyzed a recently developed Kcnt1 null mouse model in several behavioral tasks to assess which aspects of memory and learning are dependent on Slack. We demonstrate that Slack deficiency results in mildly altered general locomotor activity, but normal working memory, reference memory, as well as cerebellar control of motor functions. In contrast, we find that Slack channels are required for cognitive flexibility, including reversal learning processes and the ability to adapt quickly to unfamiliar situations and environments. Our data reveal that hippocampal-dependent spatial learning capabilities require the proper function of Slack channels.
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Affiliation(s)
- Anne E Bausch
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Rebekka Dieter
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Yvette Nann
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Mario Hausmann
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Nora Meyerdierks
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Peter Ruth
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
| | - Robert Lukowski
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, 72076 Tübingen, Germany
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Wang Y, Sakano H, Beebe K, Brown MR, de Laat R, Bothwell M, Kulesza RJ, Rubel EW. Intense and specialized dendritic localization of the fragile X mental retardation protein in binaural brainstem neurons: a comparative study in the alligator, chicken, gerbil, and human. J Comp Neurol 2015; 522:2107-28. [PMID: 24318628 DOI: 10.1002/cne.23520] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 11/09/2022]
Abstract
Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders.
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Affiliation(s)
- Yuan Wang
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle, WA, 98195-7923
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Heck DH, De Zeeuw CI, Jaeger D, Khodakhah K, Person AL. The neuronal code(s) of the cerebellum. J Neurosci 2013; 33:17603-9. [PMID: 24198351 PMCID: PMC3818542 DOI: 10.1523/jneurosci.2759-13.2013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 01/30/2023] Open
Abstract
Understanding how neurons encode information in sequences of action potentials is of fundamental importance to neuroscience. The cerebellum is widely recognized for its involvement in the coordination of movements, which requires muscle activation patterns to be controlled with millisecond precision. Understanding how cerebellar neurons accomplish such high temporal precision is critical to understanding cerebellar function. Inhibitory Purkinje cells, the only output neurons of the cerebellar cortex, and their postsynaptic target neurons in the cerebellar nuclei, fire action potentials at high, sustained frequencies, suggesting spike rate modulation as a possible code. Yet, millisecond precise spatiotemporal spike activity patterns in Purkinje cells and inferior olivary neurons have also been observed. These results and ongoing studies suggest that the neuronal code used by cerebellar neurons may span a wide time scale from millisecond precision to slow rate modulations, likely depending on the behavioral context.
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Affiliation(s)
- Detlef H. Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Chris I. De Zeeuw
- Department of Neuroscience, Erasmus MC, 3000 DR Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands
| | - Dieter Jaeger
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Kamran Khodakhah
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, and
| | - Abigail L. Person
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado 80045
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Akins MR, Leblanc HF, Stackpole EE, Chyung E, Fallon JR. Systematic mapping of fragile X granules in the mouse brain reveals a potential role for presynaptic FMRP in sensorimotor functions. J Comp Neurol 2013; 520:3687-706. [PMID: 22522693 DOI: 10.1002/cne.23123] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Loss of Fragile X mental retardation protein (FMRP) leads to Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism. Although the functions of FMRP and its homologs FXR1P and FXR2P are well studied in the somatodendritic domain, recent evidence suggests that this family of RNA binding proteins also plays a role in the axonal and presynaptic compartments. Fragile X granules (FXGs) are morphologically and genetically defined structures containing Fragile X proteins that are expressed axonally and presynaptically in a subset of circuits. To further understand the role of presynaptic Fragile X proteins in the brain, we systematically mapped the FXG distribution in the mouse central nervous system. This analysis revealed both the circuits and the neuronal types that express FXGs. FXGs are enriched in circuits that mediate sensory processing and motor planning-functions that are particularly perturbed in FXS patients. Analysis of FXG expression in the hippocampus suggests that CA3 pyramidal neurons use presynaptic Fragile X proteins to modulate recurrent but not feedforward processing. Neuron-specific FMRP mutants revealed a requirement for neuronal FMRP in the regulation of FXGs. Finally, conditional FMRP ablation demonstrated that FXGs are expressed in axons of thalamic relay nuclei that innervate cortex, but not in axons of thalamic reticular nuclei, striatal nuclei, or cortical neurons that innervate thalamus. Together, these findings support the proposal that dysregulation of axonal and presynaptic Fragile X proteins contribute to the neurological symptoms of FXS.
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Affiliation(s)
- Michael R Akins
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912, USA
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12
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Becker EBE, Stoodley CJ. Autism spectrum disorder and the cerebellum. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:1-34. [PMID: 24290381 DOI: 10.1016/b978-0-12-418700-9.00001-0] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The cerebellum has been long known for its importance in motor learning and coordination. Recently, anatomical, clinical, and neuroimaging studies strongly suggest that the cerebellum supports cognitive functions, including language and executive functions, as well as affective regulation. Furthermore, the cerebellum has emerged as one of the key brain regions affected in autism. Here, we discuss our current understanding of the role of the cerebellum in autism, including evidence from genetic, molecular, clinical, behavioral, and neuroimaging studies. Cerebellar findings in autism suggest developmental differences at multiple levels of neural structure and function, indicating that the cerebellum is an important player in the complex neural underpinnings of autism spectrum disorder, with behavioral implications beyond the motor domain.
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Affiliation(s)
- Esther B E Becker
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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Heck DH, Gu W, Cao Y, Qi S, Lacaria M, Lupski JR. Opposing phenotypes in mice with Smith-Magenis deletion and Potocki-Lupski duplication syndromes suggest gene dosage effects on fluid consumption behavior. Am J Med Genet A 2012; 158A:2807-14. [PMID: 22991245 DOI: 10.1002/ajmg.a.35601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/12/2012] [Indexed: 11/12/2022]
Abstract
A quantitative long-term fluid consumption and fluid-licking assay was performed in two mouse models with either an ∼2 Mb genomic deletion, Df(11)17, or the reciprocal duplication copy number variation (CNV), Dp(11)17, analogous to the human genomic rearrangements causing either Smith-Magenis syndrome [SMS; OMIM #182290] or Potocki-Lupski syndrome [PTLS; OMIM #610883], respectively. Both mouse strains display distinct quantitative alterations in fluid consumption compared to their wild-type littermates; several of these changes are diametrically opposing between the two chromosome engineered mouse models. Mice with duplication versus deletion showed longer versus shorter intervals between visits to the waterspout, generated more versus less licks per visit and had higher versus lower variability in the number of licks per lick-burst as compared to their respective wild-type littermates. These findings suggest that copy number variation can affect long-term fluid consumption behavior in mice. Other behavioral differences were unique for either the duplication or deletion mutants; the deletion CNV resulted in increased variability of the licking rhythm, and the duplication CNV resulted in a significant slowing of the licking rhythm. Our findings document a readily quantitated complex behavioral response that can be directly and reciprocally influenced by a gene dosage effect.
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Affiliation(s)
- Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
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Roy S, Watkins N, Heck D. Comprehensive analysis of ultrasonic vocalizations in a mouse model of fragile X syndrome reveals limited, call type specific deficits. PLoS One 2012; 7:e44816. [PMID: 22984567 PMCID: PMC3439444 DOI: 10.1371/journal.pone.0044816] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 08/14/2012] [Indexed: 11/18/2022] Open
Abstract
Fragile X syndrome (FXS) is a well-recognized form of inherited mental retardation, caused by a mutation in the fragile X mental retardation 1 (Fmr1) gene. The gene is located on the long arm of the X chromosome and encodes fragile X mental retardation protein (FMRP). Absence of FMRP in fragile X patients as well as in Fmr1 knockout (KO) mice results, among other changes, in abnormal dendritic spine formation and altered synaptic plasticity in the neocortex and hippocampus. Clinical features of FXS include cognitive impairment, anxiety, abnormal social interaction, mental retardation, motor coordination and speech articulation deficits. Mouse pups generate ultrasonic vocalizations (USVs) when isolated from their mothers. Whether those social ultrasonic vocalizations are deficient in mouse models of FXS is unknown. Here we compared isolation-induced USVs generated by pups of Fmr1-KO mice with those of their wild type (WT) littermates. Though the total number of calls was not significantly different between genotypes, a detailed analysis of 10 different categories of calls revealed that loss of Fmr1 expression in mice causes limited and call-type specific deficits in ultrasonic vocalization: the carrier frequency of flat calls was higher, the percentage of downward calls was lower and that the frequency range of complex calls was wider in Fmr1-KO mice compared to their WT littermates.
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Affiliation(s)
- Snigdha Roy
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America.
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