Entraining movement-related brain oscillations using rhythmic median nerve stimulation

Abstract

Non-invasive brain stimulation techniques delivered to cortical motor areas have been shown previously to: modulate cortical motor excitability; entrain brain oscillations; and influence motor behavior; and have therefore attracted considerable interest as potential therapeutic approaches targeted for the treatment of movement disorders. However, these techniques are most often not suitable for treatment outside of the clinic, or for use with young children. We therefore investigated directly whether rhythmic pulses of median nerve stimulation (MNS) could be used to entrain brain oscillations linked to the suppression of movement. Using electroencephalography techniques together with concurrent MNS we demonstrate that 10 pulses of rhythmic MNS, delivered at 19Hz, is sufficient to entrain Beta-band brain oscillations within the contralateral sensorimotor cortex, whereas 10-pulse trains of arrhythmic MNS does not. This approach has potential in our view to be developed into a non-drug therapeutic device suitable for use outside of the research laboratory or the clinic with brain health conditions associated by excessive movements.

The Oscillatory Effects of Rhythmic Median Nerve Stimulation

“…The only significant difference in the aftereffect seen here was greater desynchronization in the 8-12Hz band following 20Hz rhythmic stimulation compared to arrhythmic. This contrasts with recent findings which indicated that there was greater mu and beta desynchronization and increased beta rebound following 19Hz arrhythmic stimulation (Maiquez et al, 2020)(preprint). On inspection of the data reported by Maiquez and colleagues, there is a short period of increased mu suppression during and following rhythmic stimulation as seen in our data.…”

“…This suggests that the typical mu band desynchronization seen during movement is maintained in the rhythmic condition. However, further findings by the same authors also describe greater beta desynchronization and increased beta rebound following 12Hz arrhythmic stimulation (Morera Maiquez et al, 2020). We hypothesise that these differences in beta aftereffects may have arisen due to a combination of several factors.…”

“…This indicates that there is potential for the same effect to be replicated through rhythmic stimulation of peripheral nerves rather than the cortex (Asamoah et al, 2019). In fact, rhythmic median nerve stimulation (MNS) at 12Hz and 19Hz (preprint) has shown similar entrainment effects in healthy participants, using sensor level EEG analysis (Maiquez et al, 2020;Morera Maiquez et al, 2020). Furthermore, concurrent delivery of 12Hz rhythmic MNS has been shown to slow reaction times compared to arrhythmic stimulation in a choice reaction time task (Morera Maiquez et al, 2020).…”

OPM-MEG Measuring Phase Synchronization on Source Time Series: Application in Rhythmic Median Nerve Stimulation

“…Rhythmic stimulation could prove therapeutically beneficial for the diseases related to hyperexcitability within the sensorimotor cortex, such as Tourette syndrome [39], [60] and the rehabilitation about the body function, such as movement [61], speech and language [62]. Previous studies have shown that rhythmic stimulation, for example transcranial magnetic stimulation [63] and electrical stimulation [38], leads to the synchronization of oscillation response, which includes the characteristics of continuous oscillations, phase resetting in SEFs, and the increased ITPS values at stimulation frequency on somatosensory cortex [38], [64]. The measurement results using OPM-MEG in this paper replicate the aforementioned findings.…”