Brain is a surname.
Those bearing it include:
Aubrey Brain (1893–1955), British French hornistBenjamin Brain (1753-1794), British boxerBrian Brain (born 1940), British cricketerCharles Kimberlin Brain (born 1931), South African paleontologistDave Brain (1879-1959), American baseball playerDavid Brain (born 1964), Zimbabwean cricketerDennis Brain (1921-1957), British French hornistErrol Brain, New Zealand rugby playerGeorge Brain (1893-1969), Australian politicianJimmy Brain (1900-1971), British football playerJonny Brain (born 1983), British football goalkeeperLester Brain (1903–1980), Australian air force office and airline executiveLouis Brain (born 1982), English-Australian football playerMarshall Brain (born 1961), American computer scientist and entrepreneurMatias Brain (born 1974), Chilean triathletePeter Brain (born 1947), Australian bishopRussell Brain (1895–1966), British neurologistTerence Brain (born 1938), British bishopTerry Brain (born 1907), Australian rules football playerTerry Brain, Jr. (born 1938), Australian rules football playerTerry Brain (animator) (born 1956), animatorTim Brain (born 1954), British police chief