In Vivo           <sup>1</sup>           H-Magnetic Resonance Spectroscopy Study of  Amygdala-Hippocampal and Parietal Regions in Autism

Page, Lisa; Daly, Eileen; Schmitz, Nicole; Simmons, Andrew; Toal, Fiona; Deeley, Quinton; Ambery, Fiona; McAlonan, Gráinne; Murphy, Kieran C.; Murphy, Declan

doi:10.1176/ajp.2006.163.12.2189

Cited by 124 publications

(152 citation statements)

References 12 publications

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“…However, other studies have found decreased glutamate/Glx in ASD in regions including the ACC (Bernardi et al, 2011;van Elst, Maier, Fangmeier, & Endres, 2014) the basal ganglia (Horder et al, 2013); frontal and occipital cortex, the cerebellum (Devito et al, 2007) and white matter (Corrigan et al, 2013). Yet other studies have found no significant differences in glutamate / Glx levels between individuals with and without ASD in several different brain regions including parietal lobes (Horder et al, 2013;Page et al, 2006), frontal lobes (Horder et al, 2013) temporal lobes (Devito et al, 2007), and occipital lobes (Robertson, Ratai, & Kanwisher, 2015); the thalamus (Bernardi et al, 2011;Doyle-Thomas et al, 2014;Hardan et al, 2008); hippocampus (Joshi et al, 2012);and cerebellum (van Elst et al, 2014). Therefore, the literature regarding glutamate/Glx levels in ASD is mixed.…”

Section: Glutamate / Glxmentioning

confidence: 96%

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

2016

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The balance of neural excitation and inhibition (E/I balance) is often hypothesised to be altered in autism spectrum disorder (ASD). One widely held view is that excitation levels are elevated relative to inhibition in ASD. Understanding whether, and how, E/I balance may be altered in ASD is important given the recent interest in trialling pharmacological interventions for ASD which target inhibitory neurotransmitter function.Here we provide a critical review of evidence for E/I balance in ASD. We conclude that data from a number of domains provides support for alteration in excitation and inhibitory neurotransmission in ASD, but when considered collectively, the available literature provide little evidence to support claims for either a net increase in excitation or a net increase in inhibition. Strengths and limitations of available techniques are considered, and directions for future research discussed.3

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Section: Glutamate / Glxmentioning

confidence: 96%

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

2016

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“…However, inconsistent results have been reported. For example, other studies did not find abnormally reduced levels of NAA in the frontal gray matter (Chugani et al, 1999;Levitt et al, 2003;Otsuka et al, 1999), temporal lobes (Levitt et al, 2003), bilateral thalamus (Levitt et al, 2003) and the amygdala-hippocampal and parietal regions (Page et al, 2006) in autism. These inconsistencies are difficult to interpret because studies differ widely in age range and level of functioning of their participants, and technical methodology.…”

Section: Introductionmentioning

confidence: 91%

N-acetyl aspartate in autism spectrum disorders: Regional effects and relationship to fMRI activation

et al. 2007

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Rapid progress in our understanding of macrostructural abnormalities in autism spectrum disorders (ASD) has occurred in recent years. However, the relationship between the integrity of neural tissue and neural function has not been previously investigated. Single-voxel proton magnetic resonance spectroscopy and functional magnetic resonance imaging of an executive functioning task was obtained in 13 high functioning adolescents and adults with ASD and 13 agematched controls. The ASD group showed significant reductions in N-acetyl aspartate (NAA) in all brain regions combined and a specific reduction in left frontal cortex compared to controls. Regression analyses revealed a significant group interaction effect between frontal and cerebellar NAA. In addition, a significant positive semi-partial correlation between left frontal lobe NAA and frontal lobe functional activation was found in the ASD group. These findings suggest that widespread neuronal dysfunction is present in high functioning individuals with ASD. Hypothesized developmental links between frontal and cerebellar vermis neural abnormalities were supported, in that impaired neuronal functioning in the vermis was associated with impaired neuronal functioning in the frontal lobes in the ASD group. Furthermore, this study provided the first direct evidence of the relationship between abnormal functional activation in prefrontal cortex and neuronal dysfunction in ASD.

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“…In particular, the reduced size of the hippocampus and amygdala observed in autism [5,71] might be associated with deficiencies in the glutamatergic neuronal projections that originate in these regions. Abnormal concentrations of glutamine/glutamate in the amygdala and hippocampus have been reported in adults diagnosed with autism spectrum disorders, in comparison to healthy subjects [55]. Changes in glutamatergic neurotransmission might also be relevant to the abnormal synaptic function found in many genetic mouse models for autism and related syndromes [4,29,30,42,84].…”

Section: Introductionmentioning

confidence: 99%

Development of a mouse test for repetitive, restricted behaviors: Relevance to autism

Moy

Nadler

Poe

et al. 2008

Behavioural Brain Research

178

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Repetitive behavior, a core symptom of autism, encompasses stereotyped responses, restricted interests, and resistance to change. These studies investigated whether different components of the repetitive behavior domain could be modeled in the exploratory hole-board task in mice. Four inbred mouse strains, C57BL/6J, BALB/cByJ, BTBR T + tf/J, and FVB/NJ, and mice with reduced expression of Grin1, leading to NMDA receptor hypofunction (NR1 neo/neo mice), were tested for exploration and preference for olfactory stimuli in an activity chamber with a 16-hole floor-board. Reduced exploration and high preference for holes located in the corners of the chamber were observed in BALB/cByJ and BTBR T+tf/J mice. All inbred strains had initial high preference for a familiar olfactory stimulus (clean cage bedding). BTBR T + tf/J was the only strain that did not demonstrate a shift in hole preference towards an appetitive olfactory stimulus (cereal or a chocolate chip), following home cage exposure to the food. The NR1 neo/neo mice showed lower hole selectivity and aberrant olfactory stimulus preference, in comparison to wildtype controls. The results indicate that NR1 neo/neo mice have repetitive nose poke responses that are less modified by environmental contingencies than responses in wildtype mice. 25-30% of NMDA-receptor hypomorphic mice also show self-injurious responses. Findings from the olfactory studies suggest that resistance to change and restricted interests might be modeled in mice by a failure to alter patterns of hole preference following familiarization with an appetitive stimulus, and by high preference persistently Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access

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In Vivo ¹ H-Magnetic Resonance Spectroscopy Study of Amygdala-Hippocampal and Parietal Regions in Autism

Abstract: Abnormalities in glutamate/glutamine may partially underpin the pathophysiology of autistic spectrum disorders, and the authors confirm earlier reports that limbic areas are metabolically aberrant in these disorders.

Cited by 124 publications

References 12 publications

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

N-acetyl aspartate in autism spectrum disorders: Regional effects and relationship to fMRI activation

Development of a mouse test for repetitive, restricted behaviors: Relevance to autism

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In Vivo 1 H-Magnetic Resonance Spectroscopy Study of Amygdala-Hippocampal and Parietal Regions in Autism

Abstract: Abnormalities in glutamate/glutamine may partially underpin the pathophysiology of autistic spectrum disorders, and the authors confirm earlier reports that limbic areas are metabolically aberrant in these disorders.

Cited by 124 publications

References 12 publications

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

N-acetyl aspartate in autism spectrum disorders: Regional effects and relationship to fMRI activation

Development of a mouse test for repetitive, restricted behaviors: Relevance to autism

Contact Info

Product

Resources

About

In Vivo ¹ H-Magnetic Resonance Spectroscopy Study of Amygdala-Hippocampal and Parietal Regions in Autism