Bryan Kei Mantia, better known by his stage name Brain, is an American contemporary rock drummer and composer. He has played with bands such as Primus, Guns N' Roses, Praxis, and Godflesh, and with other popular performers such as Tom Waits, Serj Tankian, Bill Laswell, Bootsy Collins, and Buckethead. He has also done session work for numerous artists and bands.



Bryan Kei Mantia grew up in the South Bay city of Cupertino, CA. At an early age, his pop music interests were James Brown and Sly Stone. He was also heavily influenced by Jimi Hendrix and Led Zeppelin. He says he was into all styles of music that had a "funky groove to it."



When Mantia was 16, he began to play the drums and he really put himself into it. He worked his way up to studies with Scott Morris in San Francisco, then to the Percussion Institute of Technology in Hollywood, then classical snare studies. He wanted to read and know everything there was to know about playing drums.



Brain's recording career includes dates with artists as diverse as Tom Waits, Jon Hassell, Godflesh, Giant Robot, and the aforementioned MCM and the Monster. In the mid 80s, he became a member of the Limbomaniacs, a band made up of friends from San Jose, Cupertino, and Mountain View, California. The bands mighty rhythm section, with bassist House, guitarist M.I.R.V, and Synclavier wizard Pete Scaturro, was quite capable of thrashing rhythmic assaults like "Maniac" and the insistent "Shake It" with Troublefunk's T-Bone. Many of the bands that Brain was in The Bay Area, in the late 80's were defined by the press as "Funk Thrash" because of the common influences of funk and hard rock. The popular clubs they used to play were the IBeam, Nightbreak, The Omni, and The Berkeley Square.



When Guns n' Roses drummer Josh Freese left G n'R to join A Perfect Circle after his contract expired in March 2000, the drummer slot was left open. Buckethead, already working on the new album, Chinese Democracy, had Axl bring in one his friends and former bandmate, Bryan "Brain" Mantia.



Tim Alexander had agreed to come back to Primus to replace Brain. Throughout 2000, Mantia recorded drum tracks for the new G n'R album. He also performed at two shows in Las Vegas and at Rock In Rio 3 and he has confirmed that he will support the upcoming tour. In 2001 he appeared at a Les Claypool benefit gig with Buckethead.