Which statement about spinal tracts is false?

• A. Sensory tracts are ascending pathways
• B. Motor tracts are descending pathways
• C. Most sensory tracts originate in the brain
• D. Motor tracts are located only in white matter

Answer: (D)

Spinal tracts are bundles of axons that carry information up or down the nervous system. Sensory tracts are ascending pathways, bringing information from the body toward the brain, while motor tracts are descending pathways, delivering commands from the brain to muscles. The key point is that tracts run through white matter, but their origins aren’t confined to white matter. The cell bodies for motor commands are in gray matter of the cerebral cortex or brainstem, and their axons travel through white matter to reach the spinal cord. So saying motor tracts are located only in white matter ignores where they start. This is why the statement is false. The other ideas align with the basic directions of these pathways: sensory tracts ascend and motor tracts descend.