Entropy in Electroencephalographic Signals Modulates with Force Magnitude During Grasping – A Preliminary Report

Abstract

The ability to hold objects relies on neural processes underlying grip force control during grasping. Brain activity lateralized to contralateral hemisphere averaged over trials is associated with grip force applied on an object. However, the involvement of neural variability within-trial during grip force control remains unclear. We examined dependence of neural variability over frontal, central, and parietal regions of interest (ROI) on grip force magnitude using noninvasive electroencephalography (EEG). We utilized our existing EEG dataset comprised of healthy young adults performing an isometric force control task, cued to exert 5, 10, or 15% of their maximum voluntary contraction (MVC) across trials and received visual feedback of their grip force. We quantified variability in EEG signal via sample entropy (sequence-dependent) and standard deviation (sequence-independent measure) over ROI. We found lateralized modulation in EEG sample entropy with force magnitude over central electrodes but not over frontal or parietal electrodes. However, modulation was not observed for standard deviation in the EEG activity. These findings highlight lateralized and spatially constrained modulation in sequence-dependent, but not sequence-independent component of EEG variability. We contextualize these findings in applications requiring finer precision (e.g., prosthesis), and propose directions for future studies investigating role of neural entropy in behavior.

Keywords:

• variability
• EEG
• grip force
• lateralization
• entropy
• grasping

Disclosure Statement

The authors have no competing interests to declare that are relevant to the content of this article.

Preprint Information

An earlier version of this manuscript is available as preprint on BioRxiv (Rao et al., 2023).

Data Availability Statement

Datasets pertaining to current study are available from corresponding authors upon reasonable request.

Additional information

Funding

This work was supported by the University of Houston, Division of Research High Priority Area Research Seed Grant to PJP and the National Institutes of Health Eunice Kennedy Shriver National Institute of Child Health and Human Development (NIH/NICHD) R25HD106896 to PJP and JC-V. The dataset utilized in this study was acquired with support from the National Science Foundation Award IIS-1219231 to J C-V.