How do neurons traveling to their sensory ganglia send axons back to the alar plate?

• A. A trail of cytokines guides the axons back.
• B. Direct motor neuron connections guide them back.
• C. Glial guidance cues lead them back.
• D. They stop at the sensory ganglia and do not extend further.

Answer: (A)

Growing sensory neurons in the dorsal root ganglia extend central processes back into the spinal cord by following chemical cues emitted by their target region. A gradient of cytokines/chemokines produced by cells in the alar plate/dorsal spinal cord acts as an attractant, creating a “trail” that pulls the central axons toward the dorsal horn where they form connections with interneurons and projection neurons. This chemoattractant guidance explains how these axons reach their correct destination in the alar plate rather than stopping at the ganglion or being guided by motor neurons. Glial cues can support navigation, but the essential mechanism here is the cytokine-guided trail directing the axons inward.