What happens in the ascending pain pathway?

• A. Pain travels from peripheral neurons through the dorsal horn to the brain
• B. Pain travels from brain to spinal cord
• C. Pain travels to the cerebellum
• D. Pain is blocked at the dorsal horn

Answer: (A)

Pain signals start at peripheral nociceptors and are carried into the spinal cord through dorsal-root (spinal) entry. They first synapse in the dorsal horn, particularly in laminae where second-order neurons are activated. Those neurons cross to the opposite side of the spinal cord and then ascend to the brain via the spinothalamic tract, reaching the thalamus and onward to the somatosensory cortex for perception, with additional pathways to areas that process emotion and attention. This describes the ascending pathway from peripheral nerves through the dorsal horn to the brain, which is why it’s the best answer.

The other ideas describe different mechanisms: signals descending from brain to spinal cord modulate pain; the cerebellum isn’t the primary route for conscious pain perception; and blocking at the dorsal horn would halt transmission, not describe the normal ascending pathway.