The Effects of Subthreshold Vibratory Noise on Cortical Activity During Motor Imagery

The Effects of Subthreshold Vibratory Noise on Cortical Activity During Motor Imagery

The current study showed that imperceptible random frequency vibration applied to the fingertip during kinesthetic motor imagery led to an increase in task-related event-related desynchronization activity, indicating activity of the sensorimotor cortex and greater task discrimination.


Deepa Madathil, Associate Professor, Jindal Institute of Behavioural Sciences, O.P. Jindal Global University, Haryana, India.

Kishor Lakshminarayanan, Department of Sensors and Biomedical Engineering, School of Electronics Engineering, Vellore Institute of Technology, Vellore, India.

Rakshit Shah, Cleveland State University, Cleveland, OH, USA.

Yifei Yao, Shanghai Jiao Tong University, Shanghai, SHG, China.


Previous studies have demonstrated that both visual and proprioceptive feedback play vital roles in mental practice of movements. Tactile sensation has been shown to improve with peripheral sensory stimulation via imperceptible vibratory noise by stimulating the sensorimotor cortex. With both proprioception and tactile sensation sharing the same population of posterior parietal neurons encoding within high-level spatial representations, the effect of imperceptible vibratory noise on motor imagery-based brain–computer interface is unknown.

The objective of this study was to investigate the effects of this sensory stimulation via imperceptible vibratory noise applied to the index fingertip in improving motor imagery–based brain–computer interface performance. Fifteen healthy adults (nine males and six females) were studied. Each subject performed three motor imagery tasks, namely drinking, grabbing, and flexion–extension of the wrist, with and without sensory stimulation while being presented a rich immersive visual scenario through a virtual reality headset.

Results showed that vibratory noise increased event-related desynchronization during motor imagery compared with no vibration. Furthermore, the task classification percentage was higher with vibration when the tasks were discriminated using a machine learning algorithm. In conclusion, subthreshold random frequency vibration affected motor imagery–related event-related desynchronization and improved task classification performance.

Published in: Motor Control

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