Visual effort moderates postural cascade dynamics.

Area of Science:

• Human motor control
• Systems neuroscience
• Biophysics

Background:

• Standing still appears simple but involves multi-scale coordination.
• This coordination spans from retinal photoreceptors to limb synergies and environmental interactions.
• Understanding these dynamics is key to explaining coordinated behaviors like reaching.

Purpose of the Study:

• To investigate how visual fixation at different distances influences postural control.
• To analyze postural fluctuations using multiscale probability density function (PDF) analysis.
• To determine the role of oculomotor strain in modulating postural cascade dynamics.

Main Methods:

• Multiscale probability density function (PDF) analysis was applied to postural fluctuations.
• Participants were instructed to stand quietly while visually fixating targets at various distances.
• Oculomotor strain was manipulated by changing viewing distances.

Main Results:

• Postural fluctuations exhibited cascade dynamics similar to fluid flow.
• Fixating at comfortable distances yielded dynamics comparable to eyes-closed posture.
• Increased oculomotor strain at near/far distances significantly strengthened postural cascade dynamics.

Conclusions:

• Vision stabilizes posture by reconfiguring the body's prestressed state.
• Oculomotor strain directly impacts and strengthens postural cascade dynamics.
• These findings offer insights into the interplay between visual perception and motor control.