The　activation　of　the　prefrontal　cortex　is　a　consistent　finding　in　neuroimaging　studies　of　memory　encoding　and　retrieval.　Some　of　the　studies　have　shown　that　the　left　prefrontal　cortex　is　involved　in　the　encoding　of　information,　whereas　the　right　prefrontal　cortex　is　involved　in　the　retrieval,　which　suggests　distinct　non-overlapping　cortical　processing　of　encoding　and　retrieval　in　the　prefrontal　cortex.　Others　support　the　contrasting　view　that　similar　or　overlapping　regions　of　the　prefrontal　lobe　are　involved　in　encoding　and　retrieval　processes.　To　date,　however,　there　has　been　no　consensus　yet.　We　addressed　this　issue　in　an　event-related　fMRI　study　by　measuring　the　brain　activity　in　36　normal　subjects.　In　our　study,　the　experimental　materials　were　designed　as　the　graphic　tasks.　During　the　stage　of　encoding,　subjects　were　required　to　try　to　read　and　comprehend　the　meaning　of　the　graph,　and　then　in　the　stage　of　retrieval,　they　were　asked　to　make　judgments　in　regard　to　the　content　of　reading　comprehension.　The　direct　comparison　between　encoding　and　retrieval　tasks　showed　that　encoding　significantly　more　activated　in　right　medial　prefrontal　gyrus　(BA8/9/10)　than　retrieval;　in　contrast,　retrieval　significantly　more　activated　in　left/right　middle　prefrontal　gyrus　(BA6/10/46).　Our　findings　indicate　that　distinct　regions　in　prefrontal　cortical　areas　support　the　functional　segregation　of　memory　encoding　and　retrieval,　and　suggest　that　the　medial　prefrontal　cortex　is　more　involved　in　the　encoding　of　information,　whereas　the　lateral　prefrontal　cortex　is　more　involved　in　the　retrieval.　©　2010　IEEE.