Neural oscillations during motor imagery of complex gait: an HdEEG study

Abstract

The aim of this study was to investigate differences between usual and complex gait motor imagery (MI) task in healthy subjects using high-density electroencephalography (hdEEG) with a MI protocol. We characterized the spatial distribution of α- and β-bands oscillations extracted from hdEEG signals recorded during MI of usual walking (UW) and walking by avoiding an obstacle (Dual-Task, DT). We applied a source localization algorithm to brain regions selected from a large cortical-subcortical network, and then we analyzed α and β bands Event-Related Desynchronizations (ERDs). Nineteen healthy subjects visually imagined walking on a path with (DT) and without (UW) obstacles. Results showed in both gait MI tasks, α- and β-band ERDs in a large cortical-subcortical network encompassing mostly frontal and parietal regions. In most of the regions, we found α- and β-band ERDs in the DT compared with the UW condition. Finally, in the β band, significant correlations emerged between ERDs and scores in imagery ability tests. Overall we detected MI gait-related α- and β-band oscillations in cortical and subcortical areas and significant differences between UW and DT MI conditions. A better understanding of gait neural correlates may lead to a better knowledge of pathophysiology of gait disturbances in neurological diseases.

Exploring dynamic brain oscillations in motor imagery and low-frequency sound

“…Regarding the first point, a substantial body of research consistently highlights modulations in alpha and beta bands, often manifested by an event-related desynchronization or a power decrease in sensorimotor regions, accompanied by a concurrent increase in ipsilateral areas, particularly parieto-occipital regions (Brinkman et al, 2014; de Lange et al, 2008; Di Nota et al, 2017; McFarland et al, 2000; Pfurtscheller, 2000; Pfurtscheller & Neuper, 1997; Pfurtscheller at al., 1997; Putzolu et al, 2022). However, our findings point out a significant interindividual variability (Höller et al, 2013; Wriessnegger et al, 2020), demonstrating the diverse brain responses observed among our participants.…”

“…Thereby, EEG recording, particularly the examination of the alpha (8–12 Hz) and beta bands (13–20 Hz), has also emerged as a valuable method for probing cerebral functioning with an excellent temporal resolution, in both motor and cognitive processes. Some researchers have indicated that MI increased brain activity in contralateral sensorimotor or posterior areas, often characterized by a power decrease or an event-related desynchronization in alpha and beta bands (Brinkman et al, 2014; de Lange et al, 2008; Di Nota et al, 2017; McFarland et al, 2000; Pfurtscheller, 2000; Pfurtscheller & Neuper, 1997; Pfurtscheller et al, 1997; Putzolu et al, 2022). However, other researchers have suggested opposite outcomes in the same areas with a power increase or event-related synchronization (Jacquet et al, 2021; Marks & Isaac, 1995; Neuper et al, 2006) or no modulations at all (Kim et al, 2014).…”

Motor imagery ability scores are related to cortical activation during gait imagery

“…The data analyzed in this paper have been collected from 19 healthy adults, as described in a recent publication from our group 24 . We excluded from participation subjects (i) with previous experience with MI techniques or training, (ii) with a history of neurological diseases, or (iii) being treated with any medication that affected the central nervous system.…”

“…At last, we created the leadfield matrix that expresses the scalp potentials corresponding to each source configuration. More details about head modeling have been previously reported 24 .…”

“…We assessed the correlation between the subjects' scores obtained from MI ability tests and the electroencephalographic brain activity recorded during a gait motor imagery task. In this sub-analysis of our previous paper 24 , we focused our analysis of recorded high-density EEG signals (hdEEG) by measuring event-related desynchronization (ERD) in the theta (4 ÷ 8 Hz), alpha (8 ÷ 13 Hz), and beta frequency band (13 ÷ 30 Hz), applying a custom-developed pipeline for source localization. We hypothesized a correlation between the ability to imagine, measured using mental chronometry tests and questionnaires, and the amplitude of ERD in brain signals recorded from the cortical areas in the MI network.…”