Brian uses the D major pentatonic scale (D E F# A B) for the licks in verse 3 and subtly adds the 4th and 7th intervals from the major scale (G and C#). For the licks in the outro, Brian moves the same shape up three frets making it D minor pentatonic (D F G A C). Introducing the 6th interval (B note) adds a Dorian modal flavour to the scale.