Quick Project Snapshot
Investigating social communication in the Neuroligin 3 mouse model of Autism
Autism is a complex spectrum of disorders characterized by core behavioural deficits in social interaction, communication, and behavioural flexibility. The cause of ASD is unknown. Many gene mutations that contribute to ASD have recently been identified. These findings have lead to the development of genetic mouse models which display behavioural phenotypes mimicking ASD traits. This project takes advantage of a mouse model expressing a gene mutation coding for the Neuroligin-3 (NL3) synaptic protein identified in ASD patients. We have shown that NL3 mice show impairments in social interaction, a key criteria for validating mouse models of ASD, but other aspects of their phenotype, including communication, are not well characterised. Rodents emit audible sounds (i.e. squeaks) but communicate among themselves predominantly in the ultrasonic range of sound frequencies. Male mouse ultrasonic vocalizations consist of rapid series of ‘‘chirp-like’’ syllables, each call varies in duration, is uttered at rates of about ten per second and involves rapid sweeps in frequency. Once pitch-shifted these vocalizations are reminiscent of birdsong to the human listener. Of particular relevance to social behaviour are the ultrasonic vocalizations emitted by male mice in the presence of females or when they detect female urinary pheromones. It is believed that the vocalizations made by males are a critical step in initiating mating and represent a form of communication.
It is for this reason that multiple groups assessing genetic mouse models of ASD have reported reduced numbers of ultrasonic vocalizations as a proxy for the language impairment in ASD patients. These studies have focused on number of calls and latency to call however there is evidence to suggest that shape or waveform pattern of the call influences behaviour and may more accurately represent differences in communication. A major challenge for quantitatively assessing differences between mutant and wild-type vocalizations lies in the quantity and complexity of data which must be analysed. Mice emit between 400-1200 calls during a typical 5 minute social interaction so manual detection and classification of calls is not feasible. Additionally, although specific call types have been identified previously in the literature, it remains unclear whether mutants and wild-types even produce the same types of calls. Therefore, a novel approach is required to first automatically identify individual calls, then to classify each call type. This project will involve recording NL3 mice and WT mice communicating with female mice and then developing an automated detection and classification method using MATLAB to decode the calls. This will allow us to playback calls to female mice and search for relevant behavioural responses. We hope to identify specific genetic loci that play a role in species-specific vocalizations and are potentially implicated in disorders that involve social communication deficits.
- McOmish CE, Burrows EL, Hannan AJ. Identifying novel interventional strategies for psychiatric disorders: integrating genomics, 'enviromics' and gene-environment interactions in valid preclinical models. Br J Pharmacol. 2014 May 21.
- Burrows EL, Hannan AJ. Decanalization mediating gene-environment interactions in schizophrenia and other psychiatric disorders with neurodevelopmental etiology. Front Behav Neurosci. 2013 Nov 13;7:157.
- Burrows EL, Hannan AJ. Characterizing social behavior in genetically targeted mouse models of brain disorders. Methods Mol Biol. 2013;1017:95-104.
- McOmish CE, Burrows E, Howard M, Scarr E, Kim D, Shin HS, Dean B, van den Buuse M, Hannan AJ. Phospholipase C-beta1 knockout mice exhibit endophenotypes modeling schizophrenia which are rescued by environmental enrichment and clozapine administration. Mol Psychiatry. 2008 Jul;13(7):661-72.
- McOmish CE, Burrows EL, Howard M, Hannan AJ. PLC-beta1 knockout mice as a model of disrupted cortical development and plasticity: behavioral endophenotypes and dysregulation of RGS4 gene expression. Hippocampus. 2008;18(8):824-34.
Epigenetics and Neural Plasticity Laboratory
The Neural Plasticity Laboratory investigates gene-environment interactions and experience-dependent plasticity in the healthy and diseased brain, using a variety of experimental approaches. This includes research using a model of Huntington’s disease (HD), a tandem repeat disorder, where we are following up our discoveries regarding the beneficial effects of environmental enrichment (enhanced cognitive stimulation and physical activity) and exercise, as well as depression and dementia-like symptoms associated with abnormalities of brain plasticity. Furthermore, we recently discovered that chronic stress can accelerate onset of HD, and are investigating these neurotoxic effects of stress in HD and other brain disorders.
Many neurological and psychiatric disorders have their origins in abnormal maturation of the brain, including the billions of neurons exquisitely connected by trillions of synapses. We are also investigating how genetic and environmental factors combine to cause specific disorders of brain development and cognition, including schizophrenia and autism spectrum disorders (ASD). We are interested in the mechanisms whereby specific genes regulate maturation of the brain and are dynamically regulated by interaction with the environment in conditions like ASD and schizophrenia.
Our research links data at behavioural and cognitive levels to underlying cellular and molecular mechanisms. We use a variety of behavioural tools, including automated touchscreen testing of cognition and high-throughput data analysis of vocalization and communication, that are directly translatable to clinical tests. We are establishing the extent to which experience-dependent plasticity, including adult neurogenesis and synaptic plasticity, can modulate these behavioural and cognitive endophenotypes, in models with targeted genome editing. This cellular level of understanding is linked, in turn, to molecular mechanisms, including epigenetics, transcriptomics and proteomics.
Based on this research, and the identification of key target molecules, we are also exploring the concept of ‘enviromimetics’, therapeutics that mimic or enhance the beneficial effects of cognitive stimulation and physical exercise. One goal is to develop such therapeutic agents to help reduce the personal and societal burdens of devastating brain disorders such as schizophrenia, HD and dementia.
All Projects by this LabInvestigation of paternal influence on offspring mental healthUtilising Touchscreen technology for preclinical modeling of attention in autism spectrum disorderInvestigating social communication in the Neuroligin 3 mouse model of AutismInvestigating the inherited paternal influence on offspring cognition and behaviourExperience-dependent plasticity modulating cognitive deficits in schizophreniaGene-environment interactions modulating dementia and depression in a tandem repeat disorder
The Division of Behavioural Neuroscience focuses on the use and development of models that reflect aspects of human disorders such as addiction, anxiety, depression, schizophrenia, autism and neurodegenerative conditions such as Huntington’s disease. The Cognitive Neuroscience group additionally studies cognitive disorders caused by diseases such as stroke (cerebrovascular disease), Alzheimer's disease and other dementias from a clinical perspective.