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Beta activity in the premotor cortex is increased during stabilized as compared to normal walking

View Article: PubMed Central

ABSTRACT

Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG) during stabilized and normal walking. Subjects walked on a treadmill in two conditions, each lasting 10 min; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG) of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component (IC) analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e., lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability.

No MeSH data available.


Normalized ERSP for the same electrodes as in Figure 4. First and third row are for normal walking, second and fourth for stabilized walking.
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Figure 5: Normalized ERSP for the same electrodes as in Figure 4. First and third row are for normal walking, second and fourth for stabilized walking.

Mentions: Spectral analysis of the cleaned sensor data suggested differences between normal and stabilized walking in the lower beta band (around 18 Hz), as expected from previous studies (Wagner et al., 2012; Sipp et al., 2013). These differences, however, were not significant (Figure 4). Clear modulations in power were visible across the power spectrum (Figure 5). However, there were no significant differences between conditions (Figure 6).


Beta activity in the premotor cortex is increased during stabilized as compared to normal walking
Normalized ERSP for the same electrodes as in Figure 4. First and third row are for normal walking, second and fourth for stabilized walking.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4621867&req=5

Figure 5: Normalized ERSP for the same electrodes as in Figure 4. First and third row are for normal walking, second and fourth for stabilized walking.
Mentions: Spectral analysis of the cleaned sensor data suggested differences between normal and stabilized walking in the lower beta band (around 18 Hz), as expected from previous studies (Wagner et al., 2012; Sipp et al., 2013). These differences, however, were not significant (Figure 4). Clear modulations in power were visible across the power spectrum (Figure 5). However, there were no significant differences between conditions (Figure 6).

View Article: PubMed Central

ABSTRACT

Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG) during stabilized and normal walking. Subjects walked on a treadmill in two conditions, each lasting 10 min; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG) of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component (IC) analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e., lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability.

No MeSH data available.