According to Melzack, pain is a chemical communication that travels through a gate in the and then travels to the brain.

spinal cord

Explanation:

In 1965,Ronald Melzack and Patrick Wall put forward a theory called "gate-control theory".

According to this theory,when a pain is generated at the injured site or tissues, the pain signals does not directly reach the brain.Before reaching the brain,the signals needs to encounter certain "neurological gates" at the spinal cord level and these gates determine whether the pain signals should reach to the brain or not.

Which means that pain is only percieved if these 'gates' gives way to the pain signals.

It travels through a gate in the SPINAL CORD and then travels to the brain.

Explanation: Melzack theory suggests that pain signals are transmitted through a pain control mechanism, from the dorsal horn of the spinal cord to the brain. The mechanism explains that a non-painful stimulus/input blocks a painful stimulus from travelling to the CNS. Therefore, nonnociceptors(nerves that do not carry pain signals) become involved with the nerves that carry pain signals (nociceptors)and lead to pain inhibition.