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El-Cheikh Mohamad A, Möhrle D, Haddad FL, Rose A, Allman BL, Schmid S. Assessing the Cntnap2 knockout rat prepulse inhibition deficit through prepulse scaling of the baseline startle response curve. Transl Psychiatry 2023; 13:321. [PMID: 37852987 PMCID: PMC10584930 DOI: 10.1038/s41398-023-02629-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/27/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Many neurodevelopmental disorders, including autism spectrum disorder (ASD), are associated with changes in sensory processing and sensorimotor gating. The acoustic startle response and prepulse inhibition (PPI) of startle are widely used translational measures for assessing sensory processing and sensorimotor gating, respectively. The Cntnap2 knockout (KO) rat has proven to be a valid model for ASD, displaying core symptoms, including sensory processing perturbations. Here, we used a novel method to assess startle and PPI in Cntnap2 KO rats that allows for the identification of separate scaling components: startle scaling, which is a change in startle amplitude to a given sound, and sound scaling, which reflects a change in sound processing. Cntnap2 KO rats show increased startle due to both an increased overall response (startle scaling) and a left shift of the sound/response curve (sound scaling). In the presence of a prepulse, wildtype rats show a reduction of startle due to both startle scaling and sound scaling, whereas Cntnap2 KO rats show normal startle scaling, but disrupted sound scaling, resulting in the reported PPI deficit. These results validate that startle and sound scaling by a prepulse are indeed two independent processes, with only the latter being impaired in Cntnap2 KO rats. As startle scaling is likely related to motor output and sound scaling to sound processing, this novel approach reveals additional information on the possible cause of PPI disruptions in preclinical models.
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Affiliation(s)
- Alaa El-Cheikh Mohamad
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dorit Möhrle
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Faraj L Haddad
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Anton Rose
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Brian L Allman
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Susanne Schmid
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.
- Department of Psychology, University of Western Ontario, London, ON, Canada.
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2
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Wang X, Zhao Z, Guo J, Mei D, Duan Y, Zhang Y, Gou L. GABA B1 receptor knockdown in prefrontal cortex induces behavioral aberrations associated with autism spectrum disorder in mice. Brain Res Bull 2023; 202:110755. [PMID: 37678443 DOI: 10.1016/j.brainresbull.2023.110755] [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: 06/14/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
Autism spectrum disorder (ASD) is a set of heterogeneous neurodevelopmental disorders, characterized by social interaction deficit, stereotyped or repetitive behaviors. Apart from these core symptoms, a great number of individuals with ASD exhibit higher levels of anxiety and memory deficits. Previous studies demonstrate pronounced decrease of γ-aminobutyric acid B1 receptor (GABAB1R) protein level of frontal lobe in both ASD patients and animal models. The aim of the present study was to determine the role of GABAB1R in ASD-related behavioral aberrations. Herein, the protein and mRNA levels of GABAB1R in the prefrontal cortex (PFC) of sodium valproic acid (VPA)-induced mouse ASD model were determined by Western blot and qRT-PCR analysis, respectively. Moreover, the behavioral abnormalities in naive mice with GABAB1R knockdown mediated by recombinant adeno-associated virus (rAAV) were assessed in a comprehensive test battery consisted of social interaction, marble burying, self-grooming, open-field, Y-maze and novel object recognition tests. Furthermore, the action potential changes induced by GABAB1R deficiency were examined in neurons within the PFC of mouse. The results show that the mRNA and protein levels of GABAB1R in the PFC of prenatal VPA-induced mouse ASD model were decreased. Concomitantly, naive mice with GABAB1R knockdown exhibited ASD-like behaviors, such as impaired social interaction and communication, elevated stereotypes, anxiety and memory deficits. Patch-clamp recordings also revealed that GABAB1R knockdown provoked enhanced neuronal excitability by increasing action potential discharge frequencies. Overall, these findings support a notion that GABAB1R deficiency might contribute to ASD-like phenotypes, with the pathogenesis most likely resulting from enhanced neuronal excitability. SUBHEADINGS: GABAB1 Knockdown Induces Behavioral Aberrations with ASD.
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Affiliation(s)
- Xiaona Wang
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Children's Neurodevelopment Engineering Research Center, Zhengzhou, China.
| | - Zhengqin Zhao
- Department of Nuclear Medicine, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Jisheng Guo
- School of Basic Medical Sciences, Yantai Campus of Binzhou Medical University, Yantai City, Shandong, China
| | - Daoqi Mei
- Department of Neurology, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou, China
| | - Yongtao Duan
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Children's Neurodevelopment Engineering Research Center, Zhengzhou, China
| | - Yaodong Zhang
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Children's Neurodevelopment Engineering Research Center, Zhengzhou, China.
| | - Lingshan Gou
- Peninsula Cancer Research Center, Binzhou Medical University, Yantai, Shandong, China.
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Wang HC, Feldman DE. Degraded tactile coding in the Cntnap2 mouse model of autism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560240. [PMID: 37808857 PMCID: PMC10557772 DOI: 10.1101/2023.09.29.560240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Atypical sensory processing in autism involves altered neural circuit function and neural coding in sensory cortex, but the nature of coding disruption is poorly understood. We characterized neural coding in L2/3 of whisker somatosensory cortex (S1) of Cntnap2-/- mice, an autism model with pronounced hypofunction of parvalbumin (PV) inhibitory circuits. We tested for both excess spiking, which is often hypothesized in autism models with reduced inhibition, and alterations in somatotopic coding, using c-fos immunostaining and 2-photon calcium imaging in awake mice. In Cntnap2-/- mice, c-fos-(+) neuron density was elevated in L2/3 of S1 under spontaneous activity conditions, but comparable to control mice after whisker stimulation, suggesting that sensory-evoked spiking was relatively normal. 2-photon GCaMP8m imaging in L2/3 pyramidal cells revealed no increase in whisker-evoked response magnitude, but instead showed multiple signs of degraded somatotopic coding. These included broadening of whisker tuning curves, blurring of the whisker map, and blunting of the point representation of each whisker. These altered properties were more pronounced in noisy than sparse sensory conditions. Tuning instability, assessed over 2-3 weeks of longitudinal imaging, was also significantly increased in Cntnap2-/- mice. Thus, Cntnap2-/- mice show no excess spiking, but a degraded and unstable tactile code in S1.
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Affiliation(s)
- Han Chin Wang
- Department of Molecular & Cell Biology, and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California 94720, USA
| | - Daniel E Feldman
- Department of Molecular & Cell Biology, and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California 94720, USA
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Monday HR, Wang HC, Feldman DE. Circuit-level theories for sensory dysfunction in autism: convergence across mouse models. Front Neurol 2023; 14:1254297. [PMID: 37745660 PMCID: PMC10513044 DOI: 10.3389/fneur.2023.1254297] [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: 07/06/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Individuals with autism spectrum disorder (ASD) exhibit a diverse range of behavioral features and genetic backgrounds, but whether different genetic forms of autism involve convergent pathophysiology of brain function is unknown. Here, we analyze evidence for convergent deficits in neural circuit function across multiple transgenic mouse models of ASD. We focus on sensory areas of neocortex, where circuit differences may underlie atypical sensory processing, a central feature of autism. Many distinct circuit-level theories for ASD have been proposed, including increased excitation-inhibition (E-I) ratio and hyperexcitability, hypofunction of parvalbumin (PV) interneuron circuits, impaired homeostatic plasticity, degraded sensory coding, and others. We review these theories and assess the degree of convergence across ASD mouse models for each. Behaviorally, our analysis reveals that innate sensory detection behavior is heightened and sensory discrimination behavior is impaired across many ASD models. Neurophysiologically, PV hypofunction and increased E-I ratio are prevalent but only rarely generate hyperexcitability and excess spiking. Instead, sensory tuning and other aspects of neural coding are commonly degraded and may explain impaired discrimination behavior. Two distinct phenotypic clusters with opposing neural circuit signatures are evident across mouse models. Such clustering could suggest physiological subtypes of autism, which may facilitate the development of tailored therapeutic approaches.
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Affiliation(s)
- Hannah R. Monday
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | | | - Daniel E. Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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Mann RS, Allman BL, Schmid S. Developmental changes in electrophysiological properties of auditory cortical neurons in the Cntnap2 knockout rat. J Neurophysiol 2023; 129:937-947. [PMID: 36947880 PMCID: PMC10110732 DOI: 10.1152/jn.00029.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/13/2023] [Accepted: 03/18/2023] [Indexed: 03/24/2023] Open
Abstract
Disruptions in the CNTNAP2 gene are known to cause language impairments and symptoms associated with autism spectrum disorder (ASD). Importantly, knocking out this gene in rodents results in ASD-like symptoms that include auditory processing deficits. This study used in vitro patch-clamp electrophysiology to examine developmental alterations in auditory cortex pyramidal neurons of Cntnap2-/- rats, hypothesizing that CNTNAP2 is essential for maintaining intrinsic neuronal properties and synaptic wiring in the developing auditory cortex. Whole cell patch-clamp recordings were conducted in wildtype and Cntnap2-/- littermates at three postnatal age ranges (P8-12, P18-21, and P70-90). Consistent changes across age were seen in all measures of intrinsic membrane properties and spontaneous synaptic input. Intrinsic cell properties such as action potential half-widths, rheobase, and action-potential firing frequencies were different between wildtype and Cntnap2-/- rats predominantly during the juvenile stage (P18-21), whereas adult Cntnap2-/- rats showed higher frequencies of spontaneous and mini postsynaptic currents (sPSCs; mPSCs), with lower sPSC amplitudes. These results indicate that intrinsic cell properties are altered in Cntnap2-/- rats during the juvenile age, leading to a hyperexcitable phenotype during this stage of synaptic remodeling and refinement. Although intrinsic properties eventually normalize by reaching adulthood, changes in synaptic input, potentially caused by the differences in intrinsic membrane properties, seem to manifest in the adult age and are presumably responsible for the hyperreactive behavioral phenotype. In conjunction with a previous study, the present results also indicate a large influence of breeding scheme, i.e., pre- or postnatal environment, on the impact of Cntnap2 on cellular physiology.NEW & NOTEWORTHY This study shows that neurons in the auditory cortex of Cntnap2 knockout rats are hyperexcitable only during the juvenile age, whereas resulting changes in synaptic input persist in the adult. In conjunction with a previous study, the present results indicate that it is not the genes alone, but also the influence of pre- and postnatal environment, that shape neuronal function, highlighting the importance of early intervention in neurodevelopmental disorders.
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Affiliation(s)
- Rajkamalpreet S Mann
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Brian L Allman
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Susanne Schmid
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
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6
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Zheng A, Scott KE, Schormans AL, Mann R, Allman BL, Schmid S. Differences in Startle and Prepulse Inhibition in Contactin-associated Protein-like 2 Knock-out Rats are Associated with Sex-specific Alterations in Brainstem Neural Activity. Neuroscience 2023; 513:96-110. [PMID: 36708798 DOI: 10.1016/j.neuroscience.2023.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023]
Abstract
The contactin-associated protein-like 2 (CNTNAP2) gene encodes for the CASPR2 protein, which plays an essential role in neurodevelopment. Mutations in CNTNAP2 are associated with neurodevelopmental disorders, including autism spectrum disorder and schizophrenia. Rats with a loss of function mutation in the Cntnap2 gene show increased acoustic startle response (ASR) and decreased prepulse inhibition (PPI). The neural basis of this altered auditory processing in Cntnap2 knock-out rats is currently unknown. Auditory brainstem recordings previously revealed no differences between the genotypes. The next step is to investigate brainstem structures outside of the primary auditory pathway that mediate ASR and PPI, which are the pontine reticular nucleus (PnC) and pedunculopontine tegmentum (PPTg), respectively. Multi-unit responses from the PnC and PPTg in vivo of the same rats revealed sex-specific effects of loss of CASPR2 expression on PnC activity, but no effects on PPTg activity. Female Cntnap2-/- rats showed considerably increased PnC firing rates compared with female wildtypes, whereas the difference between the genotypes was modest in male rats. In contrast, for both females and males we found meager differences between the genotypes for PPTg firing rates and inhibition of PnC firing rates, indicating that altered firing rates of these brainstem structures are not responsible for decreased PPI in Cntnap2-/- rats. We conclude that the auditory processing changes seen in Cntnap2-/- rats are associated with, but cannot be fully explained by, differences in PnC firing rates, and that a loss of function mutation in the Cntnap2 gene has differential effects depending on sex.
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Affiliation(s)
- Alice Zheng
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
| | - Kaela E Scott
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
| | - Ashley L Schormans
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
| | - Rajkamalpreet Mann
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
| | - Brian L Allman
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
| | - Susanne Schmid
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada.
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7
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Möhrle D, Yuen M, Zheng A, Haddad FL, Allman BL, Schmid S. Characterizing maternal isolation-induced ultrasonic vocalizations in a gene-environment interaction rat model for autism. GENES, BRAIN, AND BEHAVIOR 2023:e12841. [PMID: 36751016 DOI: 10.1111/gbb.12841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/09/2023]
Abstract
Deficits in social communication and language development belong to the earliest diagnostic criteria of autism spectrum disorders. Of the many risk factors for autism spectrum disorder, the contactin-associated protein-like 2 gene, CNTNAP2, is thought to be important for language development. The present study used a rat model to investigate the potential compounding effects of autism spectrum disorder risk gene mutation and environmental challenges, including breeding conditions or maternal immune activation during pregnancy, on early vocal communication in the offspring. Maternal isolation-induced ultrasonic vocalizations from Cntnap2 wildtype and knockout rats at selected postnatal days were analyzed for their acoustic, temporal and syntax characteristics. Cntnap2 knockout pups from heterozygous breeding showed normal numbers and largely similar temporal structures of ultrasonic vocalizations to wildtype controls, whereas both parameters were affected in homozygously bred knockouts. Homozygous breeding further exacerbated altered pitch and transitioning between call types found in Cntnap2 knockout pups from heterozygous breeding. In contrast, the effect of maternal immune activation on the offspring's vocal communication was confined to call type syntax, but left ultrasonic vocalization acoustic and temporal organization intact. Our results support the "double-hit hypothesis" of autism spectrum disorder risk gene-environment interactions and emphasize that complex features of vocal communication are a useful tool for identifying early autistic-like features in rodent models.
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Affiliation(s)
- Dorit Möhrle
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Megan Yuen
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Alice Zheng
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Faraj L Haddad
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Brian L Allman
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Susanne Schmid
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
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8
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Wilde M, Constantin L, Thorne PR, Montgomery JM, Scott EK, Cheyne JE. Auditory processing in rodent models of autism: a systematic review. J Neurodev Disord 2022; 14:48. [PMID: 36042393 PMCID: PMC9429780 DOI: 10.1186/s11689-022-09458-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 08/07/2022] [Indexed: 11/19/2022] Open
Abstract
Autism is a complex condition with many traits, including differences in auditory sensitivity. Studies in human autism are plagued by the difficulty of controlling for aetiology, whereas studies in individual rodent models cannot represent the full spectrum of human autism. This systematic review compares results in auditory studies across a wide range of established rodent models of autism to mimic the wide range of aetiologies in the human population. A search was conducted in the PubMed and Web of Science databases to find primary research articles in mouse or rat models of autism which investigate central auditory processing. A total of 88 studies were included. These used non-invasive measures of auditory function, such as auditory brainstem response recordings, cortical event-related potentials, electroencephalography, and behavioural tests, which are translatable to human studies. They also included invasive measures, such as electrophysiology and histology, which shed insight on the origins of the phenotypes found in the non-invasive studies. The most consistent results across these studies were increased latency of the N1 peak of event-related potentials, decreased power and coherence of gamma activity in the auditory cortex, and increased auditory startle responses to high sound levels. Invasive studies indicated loss of subcortical inhibitory neurons, hyperactivity in the lateral superior olive and auditory thalamus, and reduced specificity of responses in the auditory cortex. This review compares the auditory phenotypes across rodent models and highlights those that mimic findings in human studies, providing a framework and avenues for future studies to inform understanding of the auditory system in autism.
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Affiliation(s)
- Maya Wilde
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lena Constantin
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peter R Thorne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Section of Audiology, School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Ethan K Scott
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.,Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Juliette E Cheyne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.
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