Reproducibility of Rolandic beta rhythm modulation in MEG and EEG

Abstract

The Rolandic beta rhythm, at ~20 Hz, is generated in the somatosensory and motor cortices and is modulated by motor activity and sensory stimuli, causing a short lasting suppression that is followed by a rebound of the beta rhythm. The rebound reflects inhibitory changes in the primary sensorimotor (SMI) cortex, and thus it has been used as a biomarker to follow the recovery of acute stroke patients. The longitudinal stability of beta rhythm modulation is a prerequisite for its use in long-term follow-ups. We quantified the reproducibility of beta rhythm modulation in healthy subjects in a 1-year-longitudinal study both for MEG and EEG at T0, one month (T1-month, n = 8) and one year (T1-year, n = 19). The beta rhythm (13-25 Hz) was modulated by fixed tactile and proprioceptive stimulations of the index fingers. The relative peak strengths of beta suppression and rebound did not differ significantly between the sessions, and inter-session reproducibility was good or excellent according to intraclass correlation-coefficient values (0.70-0.96) both in MEG and EEG. Our results indicate that the beta rhythm modulation to tactile and proprioceptive stimulation is well reproducible within one year. These results support the use of beta modulation as a biomarker in long-term follow-up studies, e.g., to quantify the functional state of the SMI cortex during rehabilitation and drug interventions in various neurological impairments.

Reproducibility of evoked and induced MEG responses to proprioceptive stimulation of the ankle joint

“…Beta modulations to active volitional wrist extension and flexion movements have demonstrated high inter-session reproducibility (Espenhahn et al, 2017). In addition, proprioceptive stimulation of the index finger has been shown to elicit highly reproducible induced fields (Illman et al, 2022). Our results are in accordance with these previous results as we also found that both peak beta suppression and rebound amplitudes have excellent reproducibility in the group level, although inter-individual variation may be substantial in the absolute response amplitudes.…”

“…The induced responses appear reproducible irrespective of stimulus modality and frequency band of interest. Good to excellent reproducibility has been reported for frequency modulations (rebound and suppression) at alpha band to a cognitive task (Burgess and Gruzelier, 1996;Vázquez-Marrufo et al, 2017), at beta band to volitional hand movement (Espenhahn et al, 2017) and at beta band to proprioceptive or tactile stimulation of index finger (Illman et al, 2022). Further evidence for the reliability of induced responses is provided by observing the responses to ongoing oscillations (induced steady-state responses).…”

“…MEG has also proven to be a highly reproducible and reliable tool investigating brain dynamics longitudinally when measurements are separated by weeks (Martín-Buro et al, 2016) or even years (Boon et al, 2021;Lew et al, 2021). In the somatosensory domain, the MEG has proven to be reproducible tool to examine proprioception (Illman et al, 2022;Piitulainen et al, 2018a) and tactile sense (Illman et al, 2022;Schaefer et al, 2004). Evoked fields to tactile stimulation (Schaefer et al, 2004) and median nerve stimulation (Solomon et al, 2015) have been used to map the SI cortex to aid e.g., surgical decision making.…”

“…MEG is a highly reproducible method investigating brain function even in an individual level. Typically, MEG responses show large inter-individual variation but within-individual variation is low, making MEG capable of following individual brain activity over weeks or years (Boon et al, 2021;Espenhahn et al, 2017;Illman et al, 2022;Lew et al, 2021;Martín-Buro et al, 2016;McCusker et al, 2021;Piitulainen et al, 2018a). Reproducibility of the cortical evoked responses has been investigated with variety of stimulus paradigms and sensory modalities primarily using EEG.…”

Event-Related Desynchronization induced by Tactile Imagery: an EEG Study

“…was statistically insignificant). βoscillations have been linked to the activity of the primary motor cortex activity as it is well known that somatosensory inputs modulate β oscillations because of motor-cortical mechanisms [56][57][58]. These effects are driven by the ascending projections to M1 [59,60] and by corticocortical connections with the somatosensory cortex [61].…”