Fronto-Parietal Brain Areas Contribute to the Online Control of Posture during a Continuous Balance Task

Area of Science:

• Neuroscience
• Motor Control
• Brain Stimulation

Background:

• Frontal and parietal cortices are implicated in postural control, but their specific roles require further elucidation.
• Understanding the neural mechanisms of postural control is vital for addressing balance disorders.

Purpose of the Study:

• To investigate the causal role of the supplementary motor area (SMA) in postural control.
• To examine how disrupting SMA affects brain network activation during a challenging balance task.
• To determine the influence of SMA disruption on postural performance under varying sensory conditions.

Main Methods:

• Utilized disruptive transcranial magnetic stimulation (TMS), specifically continuous theta burst stimulation (cTBS), over the SMA in healthy young adults.
• Assessed postural control using a continuous balance task with and without sway-referenced support surface.
• Measured brain activity using electroencephalography (EEG) to identify network alterations.

Main Results:

• cTBS over SMA led to altered postural control, indicated by a smaller increase in center of pressure variability with increasing task difficulty compared to sham stimulation.
• EEG analysis revealed that cTBS over SMA modulated neural activity within fronto-parietal regions, including the anterior cingulate (AC), cingulate gyrus (CG), and bilateral posterior parietal cortex (PPC).
• These changes in brain activity correlated with altered postural behavior, suggesting SMA influences distant fronto-parietal areas.

Conclusions:

• The supplementary motor area (SMA) plays a critical role in calibrating online postural responses.
• Disruption of the SMA impacts neural activity in distant fronto-parietal brain regions, affecting postural control.
• The anterior cingulate, cingulate gyrus, and posterior parietal cortex are essential components of the brain network for challenging postural tasks.