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Updated: Aug 30, 2025
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Combined Transcranial Magnetic Stimulation and Electroencephalography of the Dorsolateral Prefrontal Cortex
Published on: August 17, 2018
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Preconditioning prefrontal connectivity using transcranial direct current stimulation and transcranial magnetic
Isabel Alkhasli1, Felix M Mottaghy2,3,4,5, Ferdinand Binkofski1,4,5
1Section Clinical Cognitive Sciences, Department of Neurology, University Hospital, RWTH Aachen University, Aachen, Germany.
Frontiers in Human Neuroscience
|August 29, 2022
Summary
This study shows that preconditioning brain networks with transcranial direct current stimulation (tDCS) can alter subsequent effects of transcranial magnetic stimulation (TMS). Inhibiting the left dorsolateral prefrontal cortex (lDLPFC) with tDCS led to stronger functional connectivity changes after TMS.
Area of Science:
- Neuroscience
- Cognitive Science
- Neuromodulation
Background:
- Transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are non-invasive brain stimulation techniques that modulate neural activity and functional connectivity.
- The effects of tDCS and TMS are known to be influenced by the brain's baseline neuronal state.
- Understanding how to combine these techniques for targeted network modulation is crucial for advancing brain stimulation therapies.
Purpose of the Study:
- To investigate the impact of preconditioning frontal networks with tDCS on subsequent TMS-induced functional connectivity changes.
- To determine if excitatory intermittent theta-burst TMS (iTBS) over the left dorsolateral prefrontal cortex (lDLPFC) yields different functional connectivity outcomes based on prior tDCS (excitatory, inhibitory, or sham).
Main Methods:
- Thirty healthy participants received excitatory, inhibitory, or sham tDCS over the lDLPFC.
- Subsequently, an excitatory iTBS protocol was applied to the lDLPFC.
- Resting-state functional magnetic resonance imaging (fMRI) was used to measure functional connectivity before tDCS, after tDCS, and after iTBS.
Main Results:
- While the overall design showed no significant results, specific analyses revealed significant modulation of functional connectivity in areas including the anterior cingulate cortex, caudate nuclei, insula, and operculum.
- Excitatory iTBS following inhibitory tDCS to the lDLPFC resulted in more robust functional connectivity changes compared to excitatory iTBS following excitatory or sham tDCS.
- Post-hoc analyses identified specific differences in temporo-parietal and frontostriatal connectivity based on the tDCS condition (anodal vs. cathodal vs. sham).
Conclusions:
- The findings demonstrate that tDCS can effectively precondition brain networks, altering the subsequent effects of TMS on functional connectivity.
- This study provides proof-of-principle for using tDCS to modulate TMS efficacy, suggesting potential for developing targeted treatment protocols, particularly for depression using DLPFC stimulation.
