Question: Which of Neal Morse's band mates was part of the band Dream Theater?
Context: Neal Morse (born August 2, 1960) is an American singer, multi-instrumentalist, bandleader and progressive rock composer based in Nashville, Tennessee.  In 1995, he formed the progressive rock band Spock's Beard with his brother Alan and released an album which was moderately successful.  In 1999, he joined former Dream Theater co-founder Mike Portnoy, Flower Kings' Roine Stolt and Marillion's Pete Trewavas to form the super-group Transatlantic.  In 2002, Neal Morse became a born again Christian, left Spock's Beard and began a Christian rock solo career, releasing many progressive rock concept albums about his new religious faith.  In the meantime, he continued to play with Transatlantic and formed three new bands, "Yellow Matter Custard", "Flying Colors" and "The Neal Morse Band". Michael Stephen Portnoy (born April 20, 1967) is an American drummer primarily known as the former drummer, backing vocalist, and a co-founder of the progressive metal/rock band Dream Theater.  Known for his technical skill as a drummer, Portnoy has won 30 awards from the "Modern Drummer" magazine.  He co-produced six Dream Theater albums with guitarist John Petrucci, starting from "" through "Black Clouds and Silver Linings".  From "A Change of Seasons" onwards, Portnoy had been writing a significant amount of Dream Theater's lyrics.  He is the second youngest person (after Neil Peart) to be inducted into the "Modern Drummer's" "Hall of Fame", at 37 years of age. A Sort of Homecoming is a live album recorded at various locations (primarily The Theater at Madison Square Garden in New York City) by progressive metal band Dream Theater and released by the Dream Theater International Fan Club; thus, it is not part of the official Dream Theater discography.  It is named after the U2 song of the same name off their album "The Unforgettable Fire". Feel Euphoria is the seventh studio album by American progressive rock band Spock's Beard.  It was the first album the band recorded following the departure of vocalist/songwriter Neal Morse.  It marked the beginning of a more band-oriented era of songwriting, as before Neal Morse had written the bulk of the band's material, now all of the remaining band members wrote for the band, including bass player Dave Meros, who picked up his first songwriting credit in the history of the band on the song "Ghosts of Autumn". Alan Morse (born August 22, 1958) is a guitarist of the progressive rock band Spock's Beard.  He is the brother of co-founder Neal Morse, who left the band in 2002.  Morse is married to Kathryn Morse and has two children, Julia and John.  He has recorded with many artists including Chad & Jeremy, Spencer Davis, Neal Morse, and (Spock's Beard keyboardist) Ryo Okumoto.  Along with the guitar, he sings and plays the theremin, the cello, musical saw, keyboards, drums, bass & bouzouki.  Morse has a degree in electrical engineering and owns an electronics manufacturing company, DynaMetric, Inc.  Unusual for a rock guitar player, Morse does not use a pick. Testimony 2 is a progressive rock concept album by Neal Morse (his eighth studio album).  It was released on 23 May 2011, as a continuation of his first Christian prog album (Testimony) and contains three sections detailing the composer's life and conversion to Christianity.  Neal returns with his normal solo-album bandmates Mike Portnoy and Randy George, but he also features many guests, including a vocal reunion of Spock's Beard in the song "Time Changer", which focuses on Neal's past with his original band. Encores and New Songs is an album by Neal Morse.  It contains the encores from the concert that was on the "?  Live" album.  The live tracks were recorded in the Summer of 2006 at the Columbia Hall in Berlin, Germany.  It also contains band new studio recorded songs and an interview with Neal Morse.  The first track is a live version of "We All Need Some Light" which is originally from "" (AKA "StoltMorsePortnoyTrewavas") by Transatlantic.  The other four live tracks were originally from the Spock's Beard album Snow.  This is the fourteenth release in the Neal Morse Inner Circle series. This is a complete list of songs by American progressive metal band Dream Theater.  Dream Theater was formed in 1985 by guitarist John Petrucci, bassist John Myung, and drummer Mike Portnoy.  The band's current line-up consists of Petrucci, Myung, keyboardist Jordan Rudess, vocalist James LaBrie, and drummer Mike Mangini.  As of 2016, Dream Theater has released thirteen studio albums. Let's Polka is a collection of Neal Morse, Shmenge Morse, and Richard Morse doing polka along with some Christmas music and "Sola Scriptura" demos.  This is the tenth release in the Neal Morse Inner Circle series. Yellow Matter Custard is a Beatles tribute supergroup consisting of Mike Portnoy (Dream Theater, Transatlantic, OSI, Liquid Tension Experiment, Liquid Trio Experiment, Avenged Sevenfold, Flying Colors, Adrenaline Mob, The Winery Dogs, Metal Allegiance), Neal Morse ( ex-Spock's Beard, Transatlantic, Flying Colors, The Neal Morse Band), Paul Gilbert (Racer X, Mr. Big) and Matt Bissonette (Mustard Seeds, Jughead, David Lee Roth, The Squirts, Joe Satriani, Electric Light Orchestra).  Kasim Sulton (Utopia and various Todd Rundgren bands) played bass with the band in 2011, replacing Bissonette.
Answer: Mike Portnoy