Passage1 Thebrainistrulyamarvel.Aseeminglyendlesslibrary,whoseshelveshouseourmostpreciousmemoriesaswellasourlifetime'sknowledge.Butisthereapointwhereitreachescapacity?Inotherwords,canthebrainbe“full”?Theanswerisaresoundingno,because,well,brainsaremoresophisticatedthanthat.AstudypublishedinNatureNeuroscienceearlierthisyearshowsthatinsteadofjustcrowdingin,oldinformationissometimespushedoutofthebrainfornewmemoriestoform.Previousbehavioralstudieshaveshownthatlearningnewinformationcanleadtoforgetting.Butinthisstudy,researchersusednewneuroimagingtechniquestodemonstrateforthefirsttimehowthiseffectoccursinthebrain.Thepaper'sauthorssetouttoinvestigatewhathappensinthebrainwhenwetrytorememberinformationthat'sverysimilartowhatwealreadyknow.Thisisimportantbecausesimilarinformationismorelikelytointerferewithexistingknowledge,andit'sthestuffthatcrowdswithoutbeinguseful. Todothis,theyexaminedhowbrainactivitychangeswhenwetrytoremembera“target”memory,thatis,whenwetrytorecallsomethingveryspecific,atthesametimeastryingtoremembersomethingsimilar(a“competing”memory).Participantsweretaughttoassociateasingleword(say,thewordsand)withtwodifferentimages--suchasoneofMarilynMonroeandtheotherofahat.Theyfoundthatasthetargetmemorywasrecalledmoreoften,brainactivityforitincreased.Meanwhile,brainactivityforthecompetingmemorysimultaneouslyweakened.Thischangewasmostprominentinregionsnearthefrontofthebrain,suchastheprefrontalcortex,ratherthankeymemorystructuresinthemiddleofthebrain,suchasthehippocampus,whichistraditionallyassociatedwithmemoryloss.Theprefrontalcortexisinvolvedinarangeofcomplexcognitiveprocesses,suchasplanning,decisionmaking,andselectiveretrievalofmemory.Extensiveresearchshowsthispartofthebrainworksincombinationwiththehippocampustoretrievespecificmemories.Ifthehippocampusisthesearchengine,theprefrontalcortexisthefilterdeterminingwhichmemoryisthemostrelevant.Thissuggeststhatstoringinformationaloneisnotenoughforagoodmemory.Thebrainalsoneedstobeabletoaccesstherelevantinformationwithoutbeingdistractedbysimilarcompetingpiecesofinformation. Indailylife,forgettingactuallyhasclearadvantages.Imagine,forinstance,thatyoulostyourbankcard.Thenewcardyoureceivewillcomewithanewpersonalidentificationnumber(PIN).ResearchinthisfieldsuggeststhateachtimeyourememberthenewPIN,yougraduallyforgettheoldone:Thisprocessimprovesaccesstorelevantinformation,withoutoldmemoriesinterfering.Whenweacquirenewinformation,thebrainautomaticallytriestoincorporateitwithinexistinginformationbyformingassociations.Andwhenweretrieveinformation,boththedesiredandassociatedbutirrelevantinformationisrecalled.Themajorityofpreviousresearchhasfocusedonhowwelearnandremembernewinformation.Butcurrentstudiesarebeginningtoplacegreateremphasisontheconditionsunderwhichweforget,asitsimportancebeginstobemoreappreciated. Whichofthefollowingisclosestinmeaningtotheunderlinedword“resounding”inParagraph2? A.Definite. B．Repetitive.
A.正确答案A
B.Echoing. C.
D.Impressive
