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Lauer AM, Behrens D, Klump G. Acoustic startle modification as a tool for evaluating auditory function of the mouse: Progress, pitfalls, and potential. Neurosci Biobehav Rev 2017; 77:194-208. [PMID: 28327385 PMCID: PMC5446932 DOI: 10.1016/j.neubiorev.2017.03.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/23/2017] [Accepted: 03/13/2017] [Indexed: 12/16/2022]
Abstract
Acoustic startle response (ASR) modification procedures, especially prepulse inhibition (PPI), are increasingly used as behavioral measures of auditory processing and sensorimotor gating in rodents due to their perceived ease of implementation and short testing times. In practice, ASR and PPI procedures are extremely variable across animals, experimental setups, and studies, and the interpretation of results is subject to numerous caveats and confounding influences. We review considerations for modification of the ASR using acoustic stimuli, and we compare the sensitivity of PPI procedures to more traditional operant psychoacoustic techniques. We also discuss non-auditory variables that must be considered. We conclude that ASR and PPI measures cannot substitute for traditional operant techniques due to their low sensitivity. Additionally, a substantial amount of pilot testing must be performed to properly optimize an ASR modification experiment, negating any time benefit over operant conditioning. Nevertheless, there are some circumstances where ASR measures may be the only option for assessing auditory behavior, such as when testing mouse strains with early-onset hearing loss or learning impairments.
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Affiliation(s)
- Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, 515 Traylor Building, 720 Rutland Ave., Baltimore, MD 21205, USA.
| | - Derik Behrens
- Cluster of Excellence Hearing4all, Animal Physiology & Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, Carl Von Ossietzky Str. 9-11, 26111 Oldenburg, Germany
| | - Georg Klump
- Cluster of Excellence Hearing4all, Animal Physiology & Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, Carl Von Ossietzky Str. 9-11, 26111 Oldenburg, Germany
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Sittig LJ, Carbonetto P, Engel KA, Krauss KS, Palmer AA. Integration of genome-wide association and extant brain expression QTL identifies candidate genes influencing prepulse inhibition in inbred F1 mice. GENES BRAIN AND BEHAVIOR 2016; 15:260-70. [PMID: 26482417 DOI: 10.1111/gbb.12262] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 12/12/2022]
Abstract
Genetic association mapping in structured populations of model organisms can offer a fruitful complement to human genetic studies by generating new biological hypotheses about complex traits. Here we investigated prepulse inhibition (PPI), a measure of sensorimotor gating that is disrupted in a number of psychiatric disorders. To identify genes that influence PPI, we constructed a panel of half-sibs by crossing 30 females from common inbred mouse strains with inbred C57BL/6J males to create male and female F1 offspring. We used publicly available single nucleotide polymorphism (SNP) genotype data from these inbred strains to perform a genome-wide association scan using a dense panel of over 150,000 SNPs in a combined sample of 604 mice representing 30 distinct F1 genotypes. We identified two independent PPI-associated loci on Chromosomes 2 and 7, each of which explained 12-14% of the variance in PPI. Searches of available databases did not identify any plausible causative coding polymorphisms within these loci. However, previously collected expression quantitative trait locus (eQTL) data from hippocampus and striatum indicated that the SNPs on Chromosomes 2 and 7 that showed the strongest association with PPI were also strongly associated with expression of several transcripts, some of which have been implicated in human psychiatric disorders. This integrative approach successfully identified a focused set of genes which can be prioritized for follow-up studies. More broadly, our results show that F1 crosses among common inbred strains can be used in combination with other informatics and expression datasets to identify candidate genes for complex behavioral traits.
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Affiliation(s)
- L J Sittig
- Department of Human Genetics, University of Chicago, Chicago, IL
| | - P Carbonetto
- Department of Human Genetics, University of Chicago, Chicago, IL
| | - K A Engel
- Department of Human Genetics, University of Chicago, Chicago, IL
| | - K S Krauss
- Department of Human Genetics, University of Chicago, Chicago, IL
| | - A A Palmer
- Department of Human Genetics, University of Chicago, Chicago, IL.,Department of Psychiatry, University of California San Diego, San Diego, CA, USA
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Tarantino LM, Eisener-Dorman AF. Forward genetic approaches to understanding complex behaviors. Curr Top Behav Neurosci 2012; 12:25-58. [PMID: 22297575 PMCID: PMC6989028 DOI: 10.1007/7854_2011_189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Assigning function to genes has long been a focus of biomedical research.Even with complete knowledge of the genomic sequences of humans, mice and other experimental organisms, there is still much to be learned about gene function and control. Ablation or overexpression of single genes using knockout or transgenic technologies has provided functional annotation for many genes, but these technologies do not capture the extensive genetic variation present in existing experimental mouse populations. Researchers have only recently begun to truly appreciate naturally occurring genetic variation resulting from single nucleotide substitutions,insertions, deletions, copy number variation, epigenetic changes (DNA methylation,histone modifications, etc.) and gene expression differences and how this variation contributes to complex phenotypes. In this chapter, we will discuss the benefits and limitations of different forward genetic approaches that capture the genetic variation present in inbred mouse strains and present the utility of these approaches for mapping QTL that influence complex behavioral phenotypes.
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Loos M, Staal J, Pattij T, Smit AB, Spijker S. Independent genetic loci for sensorimotor gating and attentional performance in BXD recombinant inbred strains. GENES BRAIN AND BEHAVIOR 2011; 11:147-56. [DOI: 10.1111/j.1601-183x.2011.00754.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kas MJ, Kahn RS, Collier DA, Waddington JL, Ekelund J, Porteous DJ, Schughart K, Hovatta I. Translational Neuroscience of Schizophrenia: Seeking a Meeting of Minds Between Mouse and Man. Sci Transl Med 2011; 3:102mr3. [DOI: 10.1126/scitranslmed.3002917] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Takata A, Kakiuchi C, Ishiwata M, Kanba S, Kato T. Behavioral and gene expression analyses in heterozygous XBP1 knockout mice: Possible contribution of chromosome 11qA1 locus to prepulse inhibition. Neurosci Res 2010; 68:250-5. [DOI: 10.1016/j.neures.2010.07.2042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/26/2010] [Accepted: 07/28/2010] [Indexed: 11/27/2022]
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Maekawa M, Ohnishi T, Hashimoto K, Watanabe A, Iwayama Y, Ohba H, Hattori E, Yamada K, Yoshikawa T. Analysis of strain-dependent prepulse inhibition points to a role for Shmt1 (SHMT1) in mice and in schizophrenia. J Neurochem 2010; 115:1374-85. [DOI: 10.1111/j.1471-4159.2010.07039.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Yazbek SN, Spiezio SH, Nadeau JH, Buchner DA. Ancestral paternal genotype controls body weight and food intake for multiple generations. Hum Mol Genet 2010; 19:4134-44. [PMID: 20696673 DOI: 10.1093/hmg/ddq332] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Current treatments have largely failed to slow the rapidly increasing world-wide prevalence of obesity and its co-morbidities. Despite a strong genetic contribution to obesity (40-70%), only a small percentage of heritability is explained with current knowledge of monogenic abnormalities, common sequence variants and conventional modes of inheritance. Epigenetic effects are rarely tested in humans because of difficulties arranging studies that distinguish conventional and transgenerational inheritance while simultaneously controlling environmental factors and learned behaviors. However, growing evidence from model organisms implicates genetic and environmental factors in one generation that affect phenotypes in subsequent generations. In this report, we provide the first evidence for paternal transgenerational genetic effects on body weight and food intake. This test focused on the obesity-resistant 6C2d congenic strain, which carries the Obrq2a(A/J) allele on an otherwise C57BL/6J background. Various crosses between 6C2d and the control C57BL/6J strain showed that the Obrq2a(A/J) allele in the paternal or grandpaternal generation was sufficient to inhibit diet-induced obesity and reduce food intake in the normally obesity-susceptible, high food intake C57BL/6J strain. These obesity-resistant and reduced food intake phenotypes were transmitted through the paternal lineage but not the maternal lineage with equal strength for at least two generations. Eliminating social interaction between the father and both his offspring and the pregnant dam did not significantly affect food intake levels, demonstrating that the phenotype is transmitted through the male germline rather than through social interactions. Persistence of these phenotypes across multiple generations raises the possibility that transgenerational genetic effects contribute to current metabolic conditions.
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Affiliation(s)
- Soha N Yazbek
- Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Samocha KE, Lim JE, Cheng R, Sokoloff G, Palmer AA. Fine mapping of QTL for prepulse inhibition in LG/J and SM/J mice using F(2) and advanced intercross lines. GENES BRAIN AND BEHAVIOR 2010; 9:759-67. [PMID: 20597988 DOI: 10.1111/j.1601-183x.2010.00613.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Prepulse inhibition (PPI) of the startle response is a measure of sensorimotor gating, a process that filters out extraneous sensory, motor and cognitive information. Humans with neurological and psychiatric disorders, including schizophrenia, obsessive-compulsive disorder and Huntington's disease, exhibit a reduction in PPI. Habituation of the startle response is also disrupted in schizophrenic patients. In order to elucidate the genes involved in sensorimotor gating, we phenotyped 472 mice from an F(2) cross between LG/J × SM/J for PPI and genotyped these mice genome-wide using 162 single nucleotide polymorphism (SNP) markers. We used prepulse intensity levels that were 3, 6 and 12 dB above background (PPI3, PPI6 and PPI12, respectively). We identified a significant quantitative trait locus (QTL) on chromosome 12 for all three prepulse intensities as well as a significant QTL for both PPI6 and PPI12 on chromosome 11. We identified QTLs on chromosomes 7 and 17 for the startle response when sex was included as an interactive covariate and found a QTL for habituation of the startle response on chromosome 4. We also phenotyped 135 mice from an F(34) advanced intercross line (AIL) between LG/J × SM/J for PPI and genotyped them at more than 3000 SNP markers. Inclusions of data from the AIL mice reduced the size of several of these QTLs to less than 5 cM. These results will be useful for identifying genes that influence sensorimotor gaiting and show the power of AIL for fine mapping of QTLs.
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Affiliation(s)
- K E Samocha
- Department of Human Genetics, The University of Chicago, IL 60637, USA
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Archer T, Beninger RJ, Palomo T, Kostrzewa RM. Epigenetics and biomarkers in the staging of neuropsychiatric disorders. Neurotox Res 2010; 18:347-66. [PMID: 20237880 DOI: 10.1007/s12640-010-9163-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 01/29/2010] [Accepted: 02/18/2010] [Indexed: 01/05/2023]
Abstract
Epigenetics, or alterations in the phenotype or gene expression due to mechanisms other than changes in the underlying DNA sequence, reflects the sensitivity and responsiveness of human and animal brains in constantly varying circumstances regulating gene expression profiles that define the biomarkers and present the ultimate phenotypical outcomes, such as cognition and emotion. Epigenetics is associated with functionally relevant alterations to the genome in such a fashion that under the particular conditions of early, adolescent, and adult life, environmental signals may activate intracellular pathways that remodel the "epigenome," triggering changes in gene expression and neural function. Thus, genetic influences in neuropsychiatric disorders that are subject to clinical staging, epigenetics in schizophrenia, epigenetic considerations in the expression of sensorimotor gating resulting from disease conditions, biomarkers of drug use and addiction, current notions on the role of dopamine in schizophrenia spectrum disorders, and the discrete interactions of biomarkers in persistent memory were to greater or lesser extents reflected upon. The relative contributions of endophenotypes and epistasis for mediating epigenetic phenomena and the outcomes as observed in the analysis of biomarkers appear to offer a multitude of interactive combinations to further complicate the labyrinthine machinations of diagnosis, intervention, and prognosis.
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Affiliation(s)
- Trevor Archer
- Department of Psychology, University of Gothenburg, Box 500, 405 30, Gothenburg, Sweden.
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Boyle AE, Gill KJ. A verification of previously identified QTLs for cocaine-induced activation using a panel of B6.A chromosome substitution strains (CSS) and A/J x C57Bl/6J F2 mice. Psychopharmacology (Berl) 2009; 207:325-34. [PMID: 19774366 DOI: 10.1007/s00213-009-1656-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 08/25/2009] [Indexed: 02/08/2023]
Abstract
BACKGROUND The objective of this study was to confirm provisional quantitative trait loci (QTL) for cocaine-induced locomotor activation, on chromosomes 1, 5, 6, 9, 12, 15, 16, 17, and 18, previously identified in the AXB/BXA recombinant inbred (RI) and AcB/BcA recombinant congenic (RC) strains of mice derived from A/J (A) and C57BL/6J (B6) progenitors. This was accomplished through a genetic analysis of cocaine-induced activity in an AxB6 F2 cross and a phenotypic survey across a panel of B6.A chromosome substitution strains (CSS) mice. Mice were tested for cocaine-induced activity, following administration of saline and cocaine (20 mg/kg), utilizing an open-field procedure. RESULTS Among AxB6 F2 mice, differences in cocaine-induced activity were associated with loci on chromosome 1 (D1Mit305), 5 (D5Mit409), 16 (D16Mit131), and 18 (D18Mit189). A survey of the CSS panel confirmed cocaine QTLs on chromosomes 5 and 15, previously identified in RI or RC strains. Overall, the regions on chromosomes 5 and 18 represent verification of QTL previously identified in both the RC and RI strains. Additionally, the B6 allele for these QTL was consistently associated with greater relative cocaine activation. CONCLUSIONS Collectively, chromosome 5 and 18 QTL have now been replicated in multiple independent crosses derived from the A/J and C57BL/6J progenitors. The use of an in silico analysis highlighted potential candidate genes on chromosomes 5 and 18. The present results complement the targeted gene approach currently prevalent in the study of cocaine and provide a broader empirically based focus for subsequent candidate gene studies.
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Affiliation(s)
- Alan E Boyle
- Department of Psychiatry, Research Institute, McGill University Health Centre, R3-117, 1650 Cedar Avenue, Montreal, H3G 1A4, Canada
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