Assessing differential effects of single and accelerated low-frequency rTMS to the visual cortex on GABA and glutamate concentrations
| dc.contributor.author | Rafique, Sara | |
| dc.contributor.author | Steeves, Jennifer Kate Evelyn | |
| dc.date.accessioned | 2025-02-07T18:31:26Z | |
| dc.date.available | 2025-02-07T18:31:26Z | |
| dc.date.issued | 2020-09-29 | |
| dc.description.abstract | Background: The application of repetitive transcranial magnetic stimulation (rTMS) for therapeutic use in visual-related disorders and its underlying mechanisms in the visual cortex is under-investigated. Additionally, there is little examination of rTMS adverse effects particularly with regards to visual and cognitive function. Neural plasticity is key in rehabilitation and recovery of function; thus, effective therapeutic strategies must be capable of modulating plasticity. Glutamate and γ-aminobutyric acid (GABA)-mediated changes in the balance between excitation and inhibition are prominent features in visual cortical plasticity. Objectives and method: We investigated the effects of low-frequency (1 Hz) rTMS to the visual cortex on levels of neurotransmitters GABA and glutamate to determine the therapeutic potential of 1 Hz rTMS for visual-related disorders. Two rTMS regimes commonly used in clinical applications were investigated: participants received rTMS to the visual cortex either in a single 20-min session or five accelerated 20-min sessions (not previously investigated at the visual cortex). Proton (1H) magnetic resonance spectroscopy for in vivo quantification of GABA (assessed via GABA+) and glutamate (assessed via Glx) concentrations was performed pre- and post-rTMS. Results: GABA+ and Glx concentrations were unaltered following a single session of rTMS to the visual cortex. One day of accelerated rTMS significantly reduced GABA+ concentration for up to 24 hr, with levels returning to baseline by 1-week post-rTMS. Basic visual and cognitive function remained largely unchanged. Conclusion: Accelerated 1 Hz rTMS to the visual cortex has greater potential for approaches targeting plasticity or in cases with altered GABAergic responses in visual disorders. Notably, these results provide preliminary insight into a critical window of plasticity with accelerated rTMS (e.g., 24 hr) in which adjunct therapies may offer better functional outcome. We describe detailed procedures to enable further exploration of these protocols. | |
| dc.description.sponsorship | This work was supported by the Natural Sciences and Engineering Research Council of Canada (grant # 327588), the Canada First Research Excellence Fund (grant # CFREF-2015-00013), York University, and the Canada Foundation for Innovation (grant # 12807). | |
| dc.identifier.citation | Rafique, S. A., & Steeves, J. K. E. (2020). Assessing differential effects of single and accelerated low‐frequency rTMS to the visual cortex on GABA and glutamate concentrations. Brain and Behavior, 10(12), Article e01845. https://doi.org/10.1002/brb3.1845 | |
| dc.identifier.issn | 2162-3279 | |
| dc.identifier.issn | 2162-3279 | |
| dc.identifier.uri | https://doi.org/10.1002/brb3.1845 | |
| dc.identifier.uri | https://hdl.handle.net/10315/42628 | |
| dc.language.iso | en | |
| dc.publisher | Wiley Periodicals, LLC. | |
| dc.rights | Attribution 4.0 International | en |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | |
| dc.subject | Accelerated rTMS | |
| dc.subject | GABA | |
| dc.subject | Glutamate | |
| dc.subject | Magnetic resonance spectroscopy | |
| dc.subject | Repetitive TMS | |
| dc.subject | Visual cortex | |
| dc.title | Assessing differential effects of single and accelerated low-frequency rTMS to the visual cortex on GABA and glutamate concentrations | |
| dc.type | Article |
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