Describe sensory reweighting when one sensory input becomes unreliable (e.g., eyes closed on a moving platform).

• A. The CNS downweights unreliable input and upweights reliable inputs (vision, proprioception, vestibular) to maintain balance, leading to altered sway patterns depending on which senses are favored.
• B. The CNS ignores all unreliable inputs and uses only vision.
• C. The CNS increases reliance on the unreliable input to test balance.
• D. The CNS downweights all inputs equally.

Answer: (B)

Sensory reweighting means the CNS adjusts how much it trusts each sense based on how reliable it is at that moment. When one input becomes unreliable, the system downweights that input and upweights the others that remain trustworthy to keep balance.

On a moving platform with eyes closed, vision isn’t available, so the CNS reduces reliance on visual information and increases reliance on vestibular and proprioceptive cues. This shift changes the sway pattern to reflect the information those remaining senses provide about body position and platform motion. The goal is to use the most trustworthy cues to maintain stability, not to ignore unreliable inputs entirely or to rely more on the input that’s failing.