The native culture of Neural was tribal, with tribes of Hill People lead by female shamans known as Kahn-ut-tu. A major threat was the Mugato, a white-furred predatory ape with lethally poisonous bite. The only known countermeasure was the native mahko root plant, which the Kahn-ut-tu were quite skilled at administering through a traditional healing ritual. By 2254, they hadn't even learned how to forge iron.
James T. Kirk visited Neural in 2254 as part of an undercover cultural observation mission during his junior year at Starfleet Academy. The mission found the inhabitants to be a peaceful, low-technology civilization that was centuries or millennia from developing any advanced technology.
In 2268, a followup visit revealed that the inhabitants were now divided into warring factions, with some factions possessing flintlock firearms that were centuries beyond their level of technology. It was quickly discovered that the Klingon Empire contacted the planet in 2267 and was tampering with the natives by arming some of the warring factions. Fearing that the planet could fall to Klingon influence, Kirk decided to violate the Prime Directive and contact opposing factions, helping them to fight the Klingon-backed tribes.
Using an analogy derived from the "brush wars" of the 20th century where major powers fought their wars through smaller proxies, Kirk set up a Federation backed faction on Neural by providing flintlocks to the hill people that were the victims of the Klingon backed aggression. (TOS: "A Private Little War")
- List of Neural natives