The surface of Neural was generally quite similar to Earth, almost remarkably so, but with a few notable differences in native life. The native culture of Neural was tribal, with tribes of Hill People led by female shamans known as Kahn-ut-tu. A major threat was the Mugato, a white-furred predatory ape-like creature having a 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.
James T. Kirk visited Neural as a young lieutenant in 2255. The planetary survey was his first command. During his covert cultural observation he befriended the hill man Tyree. 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 while giving them gradual weapon improvements to make it appear that the natives were developing them on their own, albeit at a suspiciously accelerated rate. 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")
- See: Neural natives
The name Neural only appeared in the episode's script and was not mentioned on screen.
According to the Star Trek Encyclopedia (4th ed., vol. 2, p. 431), the planet's name was referenced in an unfilmed line from the script.
According to Star Trek: Star Charts (p. 34, "United Federation of Planets") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), this planet was known as Neural (Zeta Bootis III). The Zeta Bootis system was located in the Alpha Quadrant. The system's primary was an A-class star. This world became a protectorate of the Federation in 2268. The capital city was Kahn-ut-tu, and the dominant species were the Hill People and the Village People. In 2378, there was an estimated 27.3 million people living on this planet. A major point of interest was the Peace Bridge, and first contact with this world was made by the USS Farragut in 2254.
According to The Worlds of the Federation, in the aftermath of the events of "A Private Little War", the Hill and Village Peoples fragmented into five separate factions, all warring with each other, spurred on by the weapons provided to them by the Klingons and the Federation.