p497fig13.21 (left column) An early embodiment of nonspecific arousal was a command cell in such primitive animals as crayfish.  (right column) The songbird pattern generator is also an avalanche.  This kind of circuit raises the question of how the connections self-organize through developmental learning.<BR>||  Nonspecific arousal as a command cell.  Crayfish swimmerets (Stein 1971).  Songbird pattern generator (Fee etal 2002)+.  Motor-> RA-> HVC(RA).