Glutamate as a mediating transmitter for auditory hallucinations in schizophrenia: A 1H MRS study

Hugdahl, Kenneth; Craven, Alexander R.; Nygård, Merethe; Løberg, Else‐Marie; Berle, Jan Øystein; Johnsen, Erik; Kroken, Rune A.; Specht, Karsten; Andreassen, Ole A.; Ersland, Lars

doi:10.1016/j.schres.2014.11.015

Cited by 54 publications

(56 citation statements)

References 48 publications

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“…Previous published metabolite values were calculated as metabolite to Cr concentration ratios and compared with our quantification results. Our quantification results were generally within the range of previously published values (1-3, 7-9, 20, 21). …”

Section: Resultssupporting

confidence: 90%

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Spectral fitting using basis set modified by measuredB₀field distribution

Liu

Shen

2015

NMR Biomed.

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This study sought to demonstrate and evaluate a novel spectral fitting method to improve quantification accuracy in the presence of large magnetic field distortion, especially with high fields. Magnetic resonance spectroscopy (MRS) experiments were performed using a point resolved spectroscopy (PRESS)-type sequence at 7 Tesla. A double-echo gradient echo (GRE) sequence was used to acquire B0 maps following MRS experiments. The basis set was modified based on the measured B0 distribution within the MRS voxel. Quantification results were obtained after fitting the measured MRS data using the modified basis set. The proposed method was validated using numerical Monte Carlo simulations, phantom measurements, and by comparing occipital lobe MRS measurements under homogeneous and inhomogeneous magnetic field conditions. In vivo results acquired from voxels placed at thalamus and prefrontal cortex regions close to the frontal sinus agreed well with published values. Instead of noise-amplifying complex division, the proposed method treats field variations as part of the signal model, thereby avoiding inherent statistical bias associated with regularization. Simulations and experiments showed that the proposed approach reliably quantified results in the presence of relatively large magnetic field distortion.

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Section: Resultssupporting

confidence: 90%

“… * Published values were obtained from references 1, 2, 7, 9, and 21 Abbreviations: NAA: N-acetylaspartic acid; Cho: choline; Glu: glutamate; Gln: glutamine …”

Section: Figurementioning

confidence: 99%

Spectral fitting using basis set modified by measuredB₀field distribution

Liu

Shen

2015

NMR Biomed.

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“…Further, emerging evidence emphasized that abnormal gamma rhythm in AVH patients are due to an E/I imbalance related to glutamate NMDA receptor hypofunction 80,81 . In support, initial 1 H MR spectroscopy studies reported glutamate over-activation in cortical prefrontal and auditory brain areas 82,83 , which in turn goes along with the typical observed neural hyperexcitation of auditory cortices during AVH 84–86 . All these aspects support the notion that both structural and functional interhemispheric auditory connectivity is a relevant contributor to the degree to which language is functionally lateralized and that disturbances in this regard might be related to altered auditory and/or speech processing 87 .…”

Section: Discussionmentioning

confidence: 55%

The role of functional and structural interhemispheric auditory connectivity for language lateralization - A combined EEG and DTI study

Steinmann

Amselberg

Cheng

et al. 2018

Sci Rep

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Interhemispheric connectivity between auditory areas is highly relevant for normal auditory perception and alterations are a major factor for the development of auditory verbal hallucinations. Surprisingly, there is no combined EEG-DTI study directly addressing the role of functional and structural connectivity in the same group of subjects. Accordingly, nothing is known about the relationship between functional connectivity such as gamma-band synchrony, structural integrity of the interhemispheric auditory pathways (IAPs) and language lateralization as well as whether the gamma-band synchrony is configured on the backbone of IAPs. By applying multimodal imaging of 64-channel EEG and DTI tractography, we investigated in 27 healthy volunteers the functional gamma-band synchrony between either bilateral primary or secondary auditory cortices from eLORETA source-estimation during dichotic listening, as well as the correspondent IAPs from which fractional anisotropy (FA) values were extracted. Correlation and regression analyses revealed highest values for gamma-band synchrony, followed by FA for secondary auditory cortices, which were both significantly related to a reduced language lateralization. There was no such association between the white-matter microstructure and gamma-band synchrony, suggesting that structural connectivity might also be relevant for other (minor) aspects of information transfer in addition to gamma-band synchrony, which are not detected in the present coupling analyses. The combination of multimodal EEG-DTI imaging provides converging evidence of neural correlates by showing that both stronger pathways and increased gamma-band synchrony within one cohort of subjects are related to a reduced leftward-lateralization for language.

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“…Glutamate levels are consistently elevated across striatal(18), frontal, prefrontal, and ACC(19) regions in medication-naïve FE-SCZ patients, and medial prefrontal cortex (mPFC) Glx is elevated in unmedicated patients(20). Increased temporal and frontal Glx relates to particularly severe auditory hallucinations(21), while increased inferior parietal white matter Glx relates to symptom severity and psychotic exacerbations(22). Higher frontal Glx/Cr levels may predict poorer antipsychotic medication response(23).…”

Section: Magnetic Resonance Spectroscopymentioning

confidence: 99%

Searching for Cross-Diagnostic Convergence: Neural Mechanisms Governing Excitation and Inhibition Balance in Schizophrenia and Autism Spectrum Disorders

Foss‐Feig

Adkinson

et al. 2017

Biological Psychiatry

221

180

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Recent theoretical accounts have proposed excitation (E) and inhibition (I) imbalance as a possible mechanistic, network-level hypothesis underlying neural and behavioral dysfunction across neurodevelopmental disorders, particularly autism spectrum disorder (ASD) and schizophrenia (SCZ). These two disorders share some overlap in their clinical presentation as well as convergence in their underlying genes and neurobiology. However, there are also clear points of dissociation in terms of phenotypes and putatively affected neural circuitry. Here we highlight emerging work from the clinical neuroscience literature examining neural correlates of E/I imbalance across children and adults with ASD and adults with both chronic and early-course SCZ. We discuss findings from diverse neuroimaging studies across distinct modalities, conducted with EEG, MEG, 1H-MRS, and fMRI, including effects observed both during task and at rest. Throughout this review we discuss points of convergence and divergence in the ASD and SCZ literature, with a focus on disruptions in neural E/I balance. We also consider these findings in relation to predictions generated by theoretical neuroscience, particularly computational models predicting E/I imbalance across disorders. Finally, we discuss how human non-invasive neuroimaging can benefit from pharmacological challenge studies to reveal mechanisms in ASD and SCZ. Collectively, we attempt to shed light on shared and divergent neuroimaging effects across disorders with the goal of informing future research examining the mechanisms underlying the E/I imbalance hypothesis across neurodevelopmental disorders. We posit that such translational efforts are vital to facilitate development of neurobiologically informed treatment strategies across neuropsychiatric conditions.

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Glutamate as a mediating transmitter for auditory hallucinations in schizophrenia: A 1H MRS study

Cited by 54 publications

References 48 publications

Spectral fitting using basis set modified by measuredB₀field distribution

Spectral fitting using basis set modified by measuredB₀field distribution

The role of functional and structural interhemispheric auditory connectivity for language lateralization - A combined EEG and DTI study

Searching for Cross-Diagnostic Convergence: Neural Mechanisms Governing Excitation and Inhibition Balance in Schizophrenia and Autism Spectrum Disorders

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Glutamate as a mediating transmitter for auditory hallucinations in schizophrenia: A 1H MRS study

Cited by 54 publications

References 48 publications

Spectral fitting using basis set modified by measuredB0field distribution

Spectral fitting using basis set modified by measuredB0field distribution

The role of functional and structural interhemispheric auditory connectivity for language lateralization - A combined EEG and DTI study

Searching for Cross-Diagnostic Convergence: Neural Mechanisms Governing Excitation and Inhibition Balance in Schizophrenia and Autism Spectrum Disorders

Contact Info

Product

Resources

About

Spectral fitting using basis set modified by measuredB₀field distribution

Spectral fitting using basis set modified by measuredB₀field distribution