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Temporal Dynamics of GABA and Glx in the Visual Cortex.

Accepted version
Peer-reviewed

Type

Article

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Authors

Abstract

Magnetic resonance spectroscopy (MRS) can be used in vivo to quantify neurometabolite concentration and provide evidence for the involvement of different neurotransmitter systems (e.g., inhibitory and excitatory) in sensory and cognitive processes. The relatively low signal-to-noise ratio of MRS measurements has shaped the types of questions that it has been used to address. In particular, temporal resolution is often sacrificed in MRS studies to achieve a signal sufficient to produce a reliable estimate of neurometabolite concentration. Here we apply novel analyses with large datasets from human participants (both sexes) to reveal the dynamics of GABA+ and Glx in visual cortex while participants are at rest (with eyes closed) and compare this with changes in posterior cingulate cortex from a previously collected dataset (under different conditions). We find that the dynamic concentration of GABA+ and Glx in visual cortex drifts in opposite directions; that is, GABA+ decreases while Glx increases over time. Further, we find that in visual, but not posterior cingulate cortex, the concentration of GABA+ predicts that of Glx 120 s later, such that a change in GABA+ is correlated with a subsequent opposite change in Glx. Together, these results expose novel temporal trends and interdependencies of primary neurotransmitters in visual cortex. More broadly, we demonstrate the feasibility of using MRS to investigate in vivo dynamic changes of neurometabolites.

Description

Keywords

GABA glutamate, Glx, magnetic resonance spectroscopy, temporal dynamics, visual cortex, Female, Glutamic Acid, Humans, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Male, Visual Cortex, gamma-Aminobutyric Acid

Journal Title

eNeuro

Conference Name

Journal ISSN

2373-2822
2373-2822

Volume Title

7

Publisher

Society for Neuroscience

Rights

All rights reserved
Sponsorship
Leverhulme Trust (ECF-2017-573)
Isaac Newton Trust (17.08(o))