A brain ray is a colloquial term for a tightly-focused beam of energy that affects the Human brain.
History[]
In the 2260s, Spock was attacked by white beams fired from the Brain Ray Robot. (TOS comic: "Prince Traitor")
In 2267, while on a diplomatic visit to Vandros VII, rebel forces shot James T. Kirk and his landing party with a weapon that stimulated the imagination center of the human brain, inducing delusions. Leonard McCoy described the weapon as a brain ray. Spock was able to refocus Kirk's mind with the help of a mind meld. (TOS comic: "Eye of the Beholder")