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Front. Neurosci. | doi: 10.3389/fnins.2018.00110

Characterization of Hand Clenching in Human Sensorimotor Cortex Using High-, and Ultra-High Frequency Band Modulations of Electrocorticogram

  • 1Biomedical Engineering, University of Houston, United States
  • 2Minneapolis VA Health Care System (VHA), United States
  • 3Department of Neuroscience, University of Minnesota, United States
  • 4Capa Hospital, Istanbul University, Turkey
  • 5Department of Physiology, Medical school, Istinye University, Turkey

Functional mapping of eloquent cortex before the resection of a tumor is a critical procedure for optimizing survival and quality of life. In order to locate the hand area of the motor cortex in two patients with low-grade gliomas (LGG), we recorded electrocorticogram (ECoG) from a 113 channel hybrid high-density grid (64 large contacts with diameter of 2.7 mm and 49 small contacts with diameter of 1 mm) while they executed hand clenching movements. We investigated the spatio-spectral characteristics of the neural oscillatory activity and observed that, in both patients, the hand movements were consistently associated with a wide spread power decrease in the low frequency band (LFB: 8-32 Hz) and a more localized power increase in the high frequency band (HFB: 60-280 Hz) within the sensorimotor region. Importantly, we observed significant power increase in the ultra-high frequency band (UFB: 300-800 Hz) during hand movements of both patients within a restricted cortical region close to the central sulcus, and the motor cortical “hand knob”. Among all frequency bands we studied, the UFB modulations were closest to the central sulcus and direct cortical stimulation (DCS) positive site. Both HFB and UFB modulations exhibited different timing characteristics at different locations. Power increase in HFB and UFB starting before movement onset was observed mostly at the anterior part of the activated cortical region. In addition, the spatial patterns in HFB and UFB indicated a probable postcentral shift of the hand motor function in one of the patients. We also compared the task related subband modulations captured by the small and large contacts in our hybrid grid. We did not find any significant difference in terms of band power changes.

This study shows initial evidence that event-driven neural oscillatory activity recorded from ECoG can reach up to 800 Hz. The spatial distribution of UFB oscillations was found to be more focalized and closer to the central sulcus compared to LFB and HFB. More studies are needed to characterize further the functional significance of UFB relative to LFB and HFB.

Keywords: Hybrid High-density Grid, ECoG, Ultra-high Frequency Band, hand movement, sensorimotor, Postcentral Shift

Received: 25 Sep 2017; Accepted: 13 Feb 2018.

Edited by:

Dean Krusienski, Old Dominion University, United States

Reviewed by:

Peter Brunner, Albany Medical College, United States
Christian Herff, University of Bremen, Germany
Martin G. Bleichner, University of Oldenburg, Germany  

Copyright: © 2018 Jiang, Liu, Pellizzer, Adoseli, Karamursel, Sabanci, Sencer, Gurses and Ince. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Nuri F. Ince, University of Houston, Biomedical Engineering, Houston, TX, United States,