Stance leg and surface stability modulate cortical activity during human single leg stance.

Area of Science:

• Neuroscience
• Biomechanics
• Human Motor Control

Background:

• Mobile electroencephalography (EEG) offers insights into the brain's role in postural control.
• Previous studies linked theta and alpha frequency power changes to attentional and sensorimotor processing during balance tasks.
• Limited research exists on how the stance leg influences cortical processing during postural control.

Purpose of the Study:

• To investigate cortical activity patterns during single-leg stance on stable versus unstable surfaces.
• To determine the influence of the stance leg (left vs. right) on brain activity during postural control.
• To analyze EEG data in theta, alpha-1, and alpha-2 frequency bands using source-space analysis.

Main Methods:

• Recorded EEG and force plate data from 21 healthy males during unipedal stance (left/right) on stable and unstable surfaces.
• Employed source-space analysis to examine power spectral density in specific frequency bands (theta, alpha-1, alpha-2).
• Utilized repeated measures ANOVA to analyze the interaction effects of leg dominance and surface stability.

Main Results:

• Significant interaction effects between leg and surface stability were found in left and right motor clusters.
• Surface stability significantly affected brain activity in the fronto-central (theta), left/right motor (alpha-1), and right parieto-occipital (alpha-1/alpha-2) clusters.
• Leg-dependent changes in alpha-2 power suggest lateralized cortical processing in motor areas.

Conclusions:

• Single-leg stance performance is influenced by both the stance leg and surface stability, reflected in distinct cortical activity patterns.
• Lateralized cortical processing in motor areas during single-leg stance may be indicated by leg-dependent changes in alpha-2 power.
• Future research should consider lateralized cortical activity for interpreting postural deficits in unilateral lower limb injuries.