WordNet (r) 3.0 (2006):

think back
    v 1: recapture the past; indulge in memories; "he remembered how
         he used to pick flowers" [syn: remember, think back]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "think back":
   bring back, bring to mind, call back, call to mind, call up,
   conjure up, evoke, go back, go back over, hark back, look back,
   mind, recall, recall to mind, recapture, recollect, reevoke,
   reflect, remember, retrace, retrospect, review,
   review in retrospect, revive, see in retrospect, summon up,
   think of, use hindsight