Quantifying nonlinear contributions to cortical responses evoked by continuous wrist manipulation

Vlaar, M.P.; Solis Escalante, T.; Vardy, A.N.; van der Helm, F.C.T.; Schouten, A.C.

doi:10.1109/TNSRE.2016.2579118

Quantifying nonlinear contributions to cortical responses evoked by continuous wrist manipulation

Title

Quantifying nonlinear contributions to cortical responses evoked by continuous wrist manipulation

Author

Vlaar, M.P. (TU Delft Biomechatronics & Human-Machine Control)
Solis Escalante, T. (TU Delft Biomechatronics & Human-Machine Control)
Vardy, A.N. (TU Delft Biomechatronics & Human-Machine Control)
van der Helm, F.C.T. (TU Delft Biomechatronics & Human-Machine Control)
Schouten, A.C. (TU Delft Biomechatronics & Human-Machine Control)

Date

2017

Abstract

Cortical responses to continuous stimuli as recorded using either magneto- or electroencephalography (EEG) have shown power at harmonics of the stimulated
frequency, indicating nonlinear behavior. Even though the selection of analysis techniques depends on the linearity of the system under study, the importance of nonlinear contributions to cortical responses has not been formally
addressed.The goal of this paper is to quantify the nonlinear contributions to the cortical response obtained fromcontinuous sensory stimulation. EEG was used to record the cortical response evoked by continuousmovement of the wrist joint of healthy subjects applied with a robotic manipulator. Multisine stimulus signals (i.e., the sum of several sinusoids) elicit a periodic cortical response and allowto assess
the nonlinear contributions to the response.Wrist dynamics (relation between joint angle and torque) were successfully linearized, explaining 99% of the response. In contrast, the cortical response revealed a highly nonlinear relation;
where most power ( ∼ 80%) occurred at non-stimulated frequencies. Moreover, only 10% of the response could be explained using a nonparametric linear model. These results indicate that the recorded evoked cortical responses
are governed by nonlinearities and that linear methods do not suffice when describing the relation between mechanical stimulus and cortical response.

Subject

EEG
EMG
nonlinear
neuromuscular control

To reference this document use:

http://resolver.tudelft.nl/uuid:1ac915e3-cae9-4aa0-b508-a6abd38665a7

DOI

https://doi.org/10.1109/TNSRE.2016.2579118

ISSN

1534-4320

Source

IEEE Transactions on Neural Systems and Rehabilitation Engineering, 25 (5), 481-491

Bibliographical note

Accepted Author Manuscript