The Collaborative International Dictionary of English v.0.48:

Cerebrate \Cer"e*brate\, v. i. (Physiol.)
   To exhibit mental activity; to have the brain in action.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cerebrate
    v 1: use or exercise the mind or one's power of reason in order
         to make inferences, decisions, or arrive at a solution or
         judgments; "I've been thinking all day and getting nowhere"
         [syn: think, cogitate, cerebrate]