Research reportMouse behavioral tasks relevant to autism: Phenotypes of 10 inbred strains
Introduction
Autism is a neurodevelopmental disorder, defined in the DSM-IV by three fundamental symptoms [2]. Aberrant reciprocal social interactions include low levels of social approach, and qualitatively unusual modes of social interaction [44], [96]. Deficits in social communication include delayed development of speech and poor expressive language [76]. Stereotyped, repetitive, and ritualistic behaviors, narrow restricted interests, insistence on sameness and resistance to change in habit are components of the third defining diagnostic [18], [120]. While evidence for neuropathology in autism suggests increased brain volume [6], [8], [30], [37], [61], [62], [94], [97], [126] and other neuroanatomical changes [7], [32], [78], [95], [103], [127], and fMRI studies indicate reduced activation of the amgydala and fusiform gyrus during social tasks [43], [92], [105], there is no consistent neurological or biochemical marker for diagnosis, and the etiology of autism remains unknown. In addition, there is a lack of effective therapeutic strategies [119]. A significant genetic component for autism is supported by studies of concordance rates between identical twins [13], [35], [48], [70], [121], and candidate autism-susceptibility genes have been proposed from linkage and association analyses [11], [27], [45], [87], [93], [98], [129]. These advances in our understanding of the genetic basis of autism are leading to the development of promising mouse models that reflect genetic polymorphisms linked to autism [5], [66].
One of the challenges in the evaluation and use of mouse models for autism is to design behavioral tests that reflect the core symptoms of the disease [66], [85], [88], [100]. Without biological markers, behavioral traits with face validity to the core characteristics of autism represent one approach toward evaluating genetic contributions and potential treatments. We and other labs are engaged in developing mouse behavioral tasks with conceptual analogies to the three defining features of autism. The present study addresses the first symptom, low or aberrant social approach, and the third symptom, resistance to change in habit. The goal of the present experiments is to understand the genetic variability across inbred strains of mice on these tasks, which can then be used to identify genes in strains with unusual traits in these behavioral domains.
We have developed a mouse social approach task to assess sociability, the tendency to spend time with another conspecific, and preference for social novelty, the ability to discriminate and choose between familiar and new conspecifics [86], [89]. In this procedure, the mouse is placed in the center compartment of a three-chambered test box, and given a choice between spending time in the side containing an unfamiliar (stranger) conspecific mouse, or remaining alone. The stranger mouse is contained within a small wire cage, to allow exposure to visual, auditory, olfactory, and some tactile stimuli, while preventing aggressive or sexual interactions. Measures taken during the test include time spent in each side, entries into each side, and time spent sniffing each cage. An identical wire cage in the opposite side chamber serves as a control novel object, to measure exploration of something new that has no social valence. Adult male mice of three standard inbred strains, C57BL/6J, DBA/2J, and FVB/NJ, and the F1 hybrid B6129, demonstrated a clear preference for spending time in the proximity of another mouse, versus in proximity to a novel object, while the A/J strain did not exhibit significant levels of sociability [86], [89]. This social deficit in A/J may result from their general lack of active exploration and anxiety-like phenotype, as observed on the elevated plus maze [23], [79], [107], [115]. Using a similar task, Brodkin and colleagues [24], [102] have found low levels of social approach in mice from the BALB/cJ strain, which is also characterized by high levels of anxiety-like behaviors [12], [36], [40].
A second component of our social behavior task evaluates preference for social novelty in mice. In this phase of the test, a second unfamiliar mouse (stranger 2) is placed into the wire cage that was empty during the assessment of social approach. The test mouse then has a choice between spending time in the side with the now-familiar stranger 1, or investigating the newly-introduced stranger 2. C57BL/6J, DBA/2J, and FVB/NJ, but not A/J, showed significant preference for proximity to stranger 2, versus the already-investigated stranger 1 [86], [89].
In addition to deficits in social interaction, children with autism can show cognitive inflexibility, as seen in restricted interests, rigid adherence to schedules, insistence on sameness, and upset at changes in routine and habit. Perseveration and reversal tasks in mice have reasonable face validity to components of these symptoms. We are using reversal learning in T-maze and water maze spatial tasks to examine resistance to change in a learned pattern of behavior in mice. After reaching criterion on acquisition trials to learn the location of a food reward in the T-maze, or the location of the hidden escape platform in the water maze, the reinforcer location is switched to an opposite arm of the T-maze, or opposite quadrant of the water maze. Inbred strains of mice that fail to adapt to the new conditions for reinforcement may provide a model for the insistence on sameness characteristic of the autism phenotype.
The present study replicates and extends the mouse strain distribution on our social tasks to include six new inbred strains, C57L/J, C3H/HeJ, AKR/J, BALB/cByJ, BTBR T+tf/J, and 129S1/SvImJ, in comparison to C57BL/6J, DBA/J, FVB/NJ, and A/J. These strains were selected from the top tier of inbred mouse strains recommended by the Jackson Laboratory Mouse Phenome Project (http://www.aretha.jax.org/pub-cgi/phenome/mpdcgi). Young male mice were employed, for consistency with the approximately 4:1 ratio of boys to girls in autism [48], [49], [87]. After completion of social testing, these 10 inbred mouse strains were evaluated for reversal learning in the T-maze and/or water maze tasks. Evaluation of general health, home cage behaviors, neurological reflexes, activity in an open field, motor coordination, olfactory ability, and anxiety-related behaviors on the elevated plus-maze were conducted to control for procedural abilities necessary for the social and reversal tasks.
Section snippets
Animals
Twenty male mice from eight inbred strains, C57BL/6J, C57L/J, DBA/2J, FVB/NJ, AKR/J, A/J, BALB/cByJ, and 129S1/SvImJ, 19 male mice from the C3H/HeJ strain, and 24 male mice from the BTBR T+tf/J strain were purchased from The Jackson Laboratory, Bar Harbor, ME (JAX). An additional set of 10 male mice from the A/J strain (JAX) was independently tested for elevated plus maze performance. An additional set of 20 male mice from the AKR/J strain (JAX) was tested, due to health problems arising in the
Home cage behaviors, neurobehavioral reflexes, sensory abilities, and motor functions
Preliminary observations indicated that the mice from the 10 inbred strains appeared in good general health, without any overt impairments or aberrant responses. Table 1 describes the results of specific measures of general health, home cage behaviors, neurological reflexes, sensory abilities, and motor functions. At the initiation of testing, the majority of the inbred strains had body weights in the range of 19–21 g, with the lowest average body weight observed for the C57L/J (C57L) strain. In
Discussion
Modeling the symptoms of autism in mice presents a unique challenge. Poor language skills, idiosyncratic responses to sensory stimuli, absence of empathy and Theory of Mind, and lack of eye contact are a few examples of human symptoms [18], [44], [76], [96], [120] that are extremely difficult to parallel in mice. However, to investigate hypotheses about genes underlying autism, and to evaluate potential treatments, the field needs good behavioral tasks relevant to at least a subset of the more
Acknowledgements
The authors would like to thank Randal J. Nonneman for the photographs of the social test apparatus and water maze. Dr. Joseph Piven, Director of the University of North Carolina Autism Research Center, provided valuable insights throughout this project. Behavioral tests were conducted by the Mouse Behavioral Phenotyping Laboratory of the Neurodevelopmental Disorders Research Center, University of North Carolina. This work was supported by NIH STAART grant U54 MH66418 and NICHD grant P30
References (131)
- et al.
The effects of selective lesions within the anterior thalamic nuclei on spatial memory in the rat
Behav Brain Res
(1996) Molecular genetics and animal models in autistic disorder
Brain Res Bull
(2002)- et al.
A behavioral and neuroanatomical assessment of an inbred substrain of 129 mice with behavioral comparisons to C57BL/6J mice
Brain Res
(1999) - et al.
Three autism candidate genes: a synthesis of human genetic analysis with other disciplines
Int J Dev Neurosci
(2005) - et al.
Measuring normal and pathological anxiety-like behaviour in mice: a review
Behav Brain Res
(2001) - et al.
Link between emotional memory and anxiety states: a study by principle component analysis
Physiol Behav
(1995) - et al.
The V1a vasopressin receptor is necessary and sufficient for normal social recognition: a gene replacement study
Neuron
(2005) - et al.
Gonadal steroids influence the involvement of arginine vasopressin in social recognition in mice
Psychoneuroendocrinology
(1993) - et al.
Behavioral and physiological mouse assays for anxiety: a survey in nine mouse strains
Behav Brain Res
(2002) - et al.
Social approach-avoidance behavior of inbred mouse strains towards DBA/2 mice
Brain Res
(2004)
Evaluation of the elevated plus-maze and open-field tests for the assessment of anxiety-related behaviour in inbred mice
Behav Brain Res
Localized enlargement of the frontal cortex in early autism
Biol Psychiatry
Less white matter concentration in autism: 2D voxel-based morphometry
Neuroimage
Sex-specific development of cortical monoamine levels in mouse
Dev Brain Res
Behavioral phenotyping of transgenic and knockout mice: experimental design and evaluation of general health, sensory functions, motor abilities, and specific behavioral tests
Brain Res
No correlations between spatial and non-spatial reference memory in a T-maze task and hippocampal mossy fibre distribution in the mouse
Behav Brain Res
Peripheral pulses of oxytocin increase partner preferences in female, but not male, prairie voles
Horm Behav
Factors controlling measures of anxiety and responses to novelty in the mouse
Behav Brain Res
Stress-induced disturbances in Morris water-maze performance: interstrain variability
Physiol Behav
Postnatal loss of methyl-CpG binding protein 2 in the forebrain is sufficient to mediate behavioral aspects of Rett syndrome in mice
Biol Psychiatry
D2-like dopamine receptor mediation of social-emotional reactivity in a mouse model of anxiety: strain and experience effects
Neuropsychopharmacology
A new continuous alternation task in T-maze detects hippocampal dysfunction in mice: a strain comparison and lesion study
Behav Brain Res
Social interaction and sensorimotor gating abnormalities in mice lacking Dvl1
Cell
Identification of FOXP2 truncation as a novel cause of developmental speech and language deficits
Am J Hum Genet
Social behavior deficits in the Fmr1 mutant mouse
Behav Brain Res
Assessment of learning by the Morris water task and fear conditioning in inbred mouse strains and F1 hybrids: implications of genetic background for single gene mutations and quantitative trait loci analyses
Neuroscience
Regional brain enlargement in autism: a magnetic resonance imaging study
J Am Acad Child Adolesc Psychiatry
Striatal opioid peptide content in an animal model of spontaneous stereotypic behavior
Behav Brain Res
Diagnostic and statistical manual of mental disorders (DSM-IV)
Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2
Nat Genet
Learning in inbred mice: strain-specific abilities across three radial maze problems
Behav Genet
Effects of age on brain volume and head circumference in autism
Neurology
MRI volumes of amygdala and hippocampus in non-mentally retarded autistic adolescents and adults
Neurology
A clinicopathological study of autism
Brain
Fmr1 knockout mice: a model to study fragile X mental retardation
Cell
Disease susceptibility genes for autism
Ann Med
Behavioral phenotyping of transgenic and knockout animals: a cautionary tale
Lab Anim (NY)
Varieties of repetitive behavior in autism: comparisons to mental retardation
J Autism Dev Disord
The mouse phenome project
Genetica
Assessing autism-like behaviors in inbred strains of mice
Soc Neurosci Abstr
Genetic and behavioral differences among five inbred mouse strains commonly used in the production of transgenic and knockout mice
Genes Brain Behav
Behavioural profiles of inbred mouse strains used as transgenic backgrounds. II. Cognitive tests
Genes Brain Behav
Association between a GABRB3 polymorphism and autism
Mol Psychiatry
Identifying interactions between genes and early environment in the mouse
Genes Brain Behav
A learning deficit related to age and beta-amyloid plaques in a mouse model of Alzheimer's disease
Nature
An autosomal genomic screen for autism
Am J Med Genet (Neuropsychiatr Genet)
Autistic traits in the general population: a twin study
Arch Gen Psychiatry
Anxiety-related behaviors in the elevated zero-maze are affected by genetic factors and retinal degeneration
Behav Neurosci
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