Continuous and intermittent theta burst stimulation of primary visual cortex do not modulate resting state functional connectivity: A sham-controlled multi-echo fMRI study.

Autor: Cohan R; Centre for Vision Research, Faculty of Health and Department of Psychology, York University, Toronto, Ontario, Canada., Rafique SA; Centre for Vision Research, Faculty of Health and Department of Psychology, York University, Toronto, Ontario, Canada., Stoby KS; Centre for Vision Research, Faculty of Health and Department of Psychology, York University, Toronto, Ontario, Canada., Gorbet DJ; York MRI Facility, York University, Toronto, Ontario, Canada., Steeves JKE; Centre for Vision Research, Faculty of Health and Department of Psychology, York University, Toronto, Ontario, Canada.
Jazyk: angličtina
Zdroj: Brain and behavior [Brain Behav] 2023 May; Vol. 13 (5), pp. e2989. Date of Electronic Publication: 2023 Apr 16.
DOI: 10.1002/brb3.2989
Abstrakt: Introduction: Theta burst stimulation (TBS) is a type of rTMS protocol which has the advantage of a shorter delivery time over traditional rTMS. When applied to motor cortex, intermittent TBS (iTBS) has been shown to yield excitatory aftereffects, whereas continuous TBS (cTBS) may lead to inhibitory aftereffects, both lasting from minutes to hours. The majority of TBS research has targeted motor, frontal, and parietal regions, and to date very few studies have examined its efficacy at visual areas. We designed a sham-controlled study to investigate the immediate poststimulation and short-term (1 h post-stimulation) effects of iTBS and cTBS to V1.
Methods: Using multiecho functional magnetic resonance imaging, we measured the direct and indirect effects of TBS by comparing resting state functional connectivity (FC) before and after stimulation in whole brain networks, and seeds from V1 (stimulation site) and neighboring occipital and parietal visual networks. In addition, we also measured pre- and post-TBS phosphene thresholds (PTs) to examine the modulatory effects of TBS on cortical excitability.
Results: We found no changes in FC for iTBS, cTBS or sham stimulation conditions from baseline to poststimulation timepoints. Additionally, cTBS and iTBS had no effect on visual cortical excitability.
Conclusions: Our results indicate that unlike our previous low frequency rTMS to V1 study, which resulted in widespread FC changes up to at least 1 h after stimulation, TBS to V1 does not affect FC. Contrary to the studies showing comparable TBS and rTMS aftereffects in motor and frontal regions, our findings suggest that a single session of cTBS or iTBS to V1 at 80% PT using a standard protocol of 600 pulses may not be effective in targeting FC, especially in clinical settings where therapy for pathological networks is the goal.
(© 2023 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)
Databáze: MEDLINE
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