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bioRxiv · 10.1101/2024.05.29.596317

Real-time optimization to enhance noninvasive cortical excitability assessment in the human dorsolateral prefrontal cortex

Parmigiani, S.·Cline, C. C.·Sarkar, M.·Forman, L.·Truong, J.·Ross, J. M.·Gogulski, J.·Keller, C. J.
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Abstract

ObjectiveWe currently lack a robust noninvasive method to measure prefrontal excitability in humans. Concurrent TMS and EEG in the prefrontal cortex is usually confounded by artifacts. Here we asked if real-time optimization could reduce artifacts and enhance a TMS-EEG measure of left prefrontal excitability. MethodsThis closed-loop optimization procedure adjusts left dlPFC TMS coil location, angle, and intensity in real-time based on the EEG response to TMS. Our outcome measure was the left prefrontal early (20-60 ms) and local TMS-evoked potential (EL-TEP). ResultsIn 18 healthy participants, this optimization of coil angle and brain target significantly reduced artifacts by 63% and, when combined with an increase in intensity, increased EL-TEP magnitude by 75% compared to a non-optimized approach. ConclusionsReal-time optimization of TMS parameters during dlPFC stimulation can enhance the EL-TEP. SignificanceEnhancing our ability to measure prefrontal excitability is important for monitoring pathological states and treatment response. HighlightsO_LIWe developed a real-time closed-loop optimization procedure to obtain high amplitude early local TEPs (EL-TEPs) from dlPFC TMS. C_LIO_LISequential optimization of coil angle and brain target reduced artifacts by 63%. C_LIO_LISequential optimization of coil angle, brain target, and intensity increased EL-TEP amplitude by 75%. C_LI

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Parmigiani, S., Cline, C. C., Sarkar, M., Forman, L., Truong, J., Ross, J. M., Gogulski, J., Keller, C. J.. 2024-05-31. Real-time optimization to enhance noninvasive cortical excitability assessment in the human dorsolateral prefrontal cortex. https://doi.org/10.1101/2024.05.29.596317

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