How do proprioceptive and vestibular inputs integrate to support balance, and what happens when there is sensory conflict?

• A. Proprioceptive inputs alone govern balance; vestibular input is not used.
• B. Visual cues alone determine balance; proprioception not involved.
• C. CNS combines proprioceptive (body position) with vestibular and visual cues to maintain posture; conflicting cues can cause dizziness and postural instability.
• D. Vestibular inputs disrupt proprioception during conflict.

Answer: (C)

Balance relies on the brain combining information about body position from proprioception with signals about head movement and orientation from the vestibular system, and environmental cues from vision. The CNS integrates these inputs, weighting each cue by how reliable it is in the current situation, to create a coherent sense of posture and to guide balance and movement.

When the cues don’t line up—a sensory conflict—the brain must reassess which signals to trust more. This sensory reweighting can lead to dizziness, instability, and increased sway because the integration process is temporarily uncertain as the system tries to resolve the mismatch. In normal conditions, all three systems contribute to stable balance, and when they align, posture is maintained smoothly.