AUTHOR=Mitsuhashi Takumi , Iimura Yasushi , Suzuki Hiroharu , Ueda Tetsuya , Nishioka Kazuki , Nomura Kazuki , Nakajima Madoka , Sugano Hidenori , Kondo Akihide 

TITLE=Bipolar and Laplacian montages are suitable for high-gamma modulation language mapping with stereoelectroencephalography

JOURNAL=Frontiers in Neurology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2024.1380644

DOI=10.3389/fneur.2024.1380644

ISSN=1664-2295

ABSTRACT=Objective: To determine the optimal montage and vocalization conditions for high-gamma language mapping using stereoelectroencephalography.
Methods: We studied 12 epilepsy patients who underwent invasive monitoring with depth electrodes and measurement of auditory-naming related high-gamma modulations. We determined the effects of electrode montage and vocalization conditions of the response on the high-gamma (60-140 Hz) amplitudes.
Results: Compared to common average reference montage, bipolar and Laplacian montages effectively reduced the degree of auditory naming-related signal deflections in the white matter during the stimulus and response phases (mixed model estimate: -21.2 to -85.4%; p<0.001), while maintaining those at the cortical level (-4.4 to +7.8%; p=0.614 to 0.085). They also reduced signal deflections outside the brain parenchyma during the response phase (-90.6 to -91.2%; p<0.001). Covert responses reduced signal deflections outside the brain parenchyma during the response phase (-17.0%; p=0.010).
Conclusions: On depth electrode recording, bipolar and Laplacian montages are suitable for measuring auditory naming-related high-gamma modulations in gray matter. The covert response may highlight the gray matter activity.
Significance: This study helps establish the practical guidelines for high-gamma language mapping using stereoelectroencephalography.