Neural

Neural was an inhabited M class planet. This was the homeworld of a native pre-warp capable species. The planet was, also, the home for the Mugato and the Mahko root.

Prior to stardate 4211, the civilization of Neural was protected under the terms of the Prime Directive.

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 hillman 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. 

People

 * Apella
 * Nona
 * Tyree
 * Yutan
 * List of unnamed Neural inhabitants

Background
The name Neural only appeared in the episode's script and was not mentioned on screen.

Presumably, Neural was located in the Alpha Quadrant.

Star Trek: Star Charts

 * Neural (or Zeta Bootis III): This world became a protectorate of the Federation in 2268. The capital 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 (23rd century) in 2254. In 2378, Neural was a Federation member.


 * Zeta Bootis: This planetary system was located in non-aligned space, in the Alpha Quadrant. This system was a single star system. Zeta Bootis was an A-class star with a magnitude of +3, which was ten times brighter than Sol. (Pg. 34, "United Federation of Planets I")