In reactive postural control, which processing sequence is most accurate?

• A. Sensory input -> conscious processing -> nonconscious processing -> automatic motor output
• B. Sensory input -> nonconscious processing -> conscious processing -> automatic motor output
• C. Automatic motor output -> sensory input -> nonconscious processing -> conscious processing
• D. Nonconscious processing -> sensory input -> conscious processing -> automatic motor output

Answer: (B)

In reactive postural control, the process begins with sensing the perturbation through sensory inputs, such as vision, vestibular signals, and somatosensory feedback. The initial response is driven by nonconscious processing, which quickly translates those sensory cues into fast, automatic adjustments to the posture without deliberate thought. If the automatic response is insufficient or if the situation requires a more strategic approach, conscious processing steps in to interpret context, prioritize goals, and fine-tune the plan. After this assessment, the motor system executes the chosen strategy as automatic motor output, producing the actual muscle actions to restore balance. This sequence—rapid nonconscious processing following sensory input, with potential conscious modulation, culminating in automatic motor output—captures how the body balances speed with adaptability during unexpected disturbances.