生物醫(yī)學(xué)工程(biomedical-engineering)

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ALittlePaperaboutScienceandTechnology:CaseStudyofBrain–computerInterface

Abstract:Brain-computerinterfacesprovideadirectcommunicationandcontrolchannelforsendingmessagesandinstructionsfrombraintoexternalcomputersorotherelectronicdevices.Usingthenon-muscularchannel,subjectswithsevereneuromusculardysfunctioncandirectlyexpresstheirthoughtandmanipulatetheexternaldeviceswithoutusinghumanlanguageandactions.Thiswillgreatlyenhancetheabilityofthesesubjectstomanageexternaleventandwillimprovetheirlivingquality.Brain-computerinterfacetechnologyisaninterdisciplinarytechnologyintegratingneurology,signalcollection,signalprocessing,patternrecognitionandmoreotherrelevanttechniques.Inthepresentpaper,wereviewthedevelopment,therationaleandthemethodologyofBCI’stechnologyandthemajorlimitationsintheBCI’simplementationandapplications,andthendiscusssomevitalaspectsthatmaybeconductedinthefutureinvestigations.

Keywords:brain-computerinterface;electroencephalogram;event2relatedpotentials;featureextraction;communication

1.Introduction

Theultimatepurposeofadirectbrain-computerinterface(BCI)istoallowanindividualwithseveremotordisabilitiestohaveeffectivecontroloverdevicessuchascomputers,speechSynthesizers,assistiveappliancesandneuralprostheses.Suchaninterfacewouldincreaseanindividual’sindependence,leadingtoanimprovedqualityoflifeandreducedsocialcosts.

ABCIsystemdetectsthepresenceofspecificpatternsinaperson’songoingbrainactivitythatrelatestotheperson’sintentiontoinitiatecontrol.TheBCIsystemtranslatesthesepatternsintomeaningfulcontrolcommands[1].Todetectthesepatterns,varioussignalprocessingalgorithmsareemployed.SignalprocessingformsanimportantpartofaBCIdesign,sinceitisneededinextractingthemeaningfulinformationfromthebrainsignal.

2.GeneralstructureofaBCIsystem

AtypicalBrainComputerinterfaceisshownintheFig.1．Itconsistsofelectrodesappliedtothescalpofthesubjectthatpickupthebrain’sactivityandforwardittoanamplifierasthesesignalsareatmicrolevel．Theamplifieramplifythesignalaroundtenthousandandthenpassviaanalogtoadigitalconvertertoacomputerforprocessing.ThecomputerprocessestheEEGsignalinordertoextractthesignalfeaturethatencodestheuser’smessageorcommand.BCIsareslowincomparisontonormalhumanactionandothercommunicationsystemsbecauseofthecomplexityandnoisinessofthesignalsused,andalsoduetothetimerequiredtocompleterecognitionandsignalprocessing[2].

BCIsperformsignalprocessing,anddependoncomputerhardwareandsoftware.Theyincorporateadaptationroutinesthatdependonlearningprinciplesandotherhumanfactorslikeattention，motivation，andfatigue[3]．BCIoutputscontroldevicesthatspecifyelectronicsand/ormechanicalcharacteristicsandprovidefeedbackthatengagestheuser’sperceptiveandreactivecapacities.Finally,BCIoperatingprotocolsorchestratesoperationinaccordwiththecharacterist-

icsoftheinputs，featuresextractionmethods，translationalgorithmsandoutputs.

Fig.1BCIsystem

BCIresearchisamultidisciplinaryfieldintegratingresearchfromneuroscience,physiology,psychology,engineering,computerscience,rehabilitation,andothertechnicalandhealthcaredisciplines[4].TherehavebeenseveralvariedapproachestothedesignofBCIs.WhilealltheBCIresearchprogramssharethesamegoal:rapidandaccuratecommunicationandcontrol,theydifferwidelynotonlyintheirinputs,featureextractionmethods,translationalgorithms,outputs,andoperatingprotocols,butalsointheirimmediateobjectives.Somefocusonspecificapplicationlikewordprocessingorneuroprosthesiscontrol,whileotherconcentrateonestablishinggeneralfeaturesofBCIdesignandoperationanduseaprototypeapplicationsuchascursorcontroltodoso.Whatevertheirobjective,allneedhardwareandsoftwarethatcanacquireelectrophysiologicalinputwithsufficientrateandprecision.Translateittooutputquicklyenoughtocontroldeviceswithacceptabledelays,andmanageadaptiveinteractionbetweenuserandsystem.Sincethepurposeisresearchtheyalsoneedtostorecompletedataforlaterevaluation[5].

3.Towardsthefuture

Likeothernewandpromisingresearchareas,suchasbioinformaticsandnanotechnology,BCIprovidescauseforconsideringitspotentialphilosophical,ethicalandsocietalconsequences.ResearchinBCIhasimplicationsforandcanbein?uencedbydiscussionsofgeneraltopicswithinneuroethics,rangingfrommind-readingandprivacy,personalidentity,freewillandmind-control,tohumanenhancementandsocialstrati?cation[6].

Thereal-timesingle-trialanalysisaffordedbyBCImayalsohaveaprofoundimpactonthewayneurophysiologicdataareanalyzed[7].Traditionalunivariateanalysisofdatawhichisaveragedovermultipletrialsandsubjectscannowbeaugmentedbysensitivemultivariatemethodsthatallow(on-line)theclassi?cationofsingle-trialdatainsinglesubjects.Recentadvancesinsingle-trialanalysishaveledtoanincreasedinterestinbrainreading,wherethegoalistoinferthecontentsofsubjectiveperceptiongivenknowledgeoftheobservedbrainstate.Thisincreasedfocusonreal-timesingle-trialanalysisshouldultimatelyincreaseourunderstandingofhumancognition.

4.Conclusions

BCItechnologyresearchhasimportanttheoreticalsignificanceandwideapplicationprospects.SincethedevelopmentofBCItechnologylatestart,thecorrespondingtheoryandalgorithmisveryimmature,verycompletestudyofitsapplication,tobemorecommittedtothisareaofscienceandtechnologyworkersstudy.Astechnologycontinuestoimproveandmature,BCIwillbegraduallyappliedtoreality,andopenupnewfieldsofapplicationofbionics.BasedontheextensiveliteratureonthebasisofinspectionofBCItechnologyworks,thekeytechnologiesandotherissuesinamoredetailedoverviewofthefieldthatThemainproblemsandprospectsofdevelopmentofthefielddirection.

5.Acknowledgements

IwouldliketotakethisopportunitytoexpressmyheartfeltthankstomyteacherZhangHu,whooffersmetheabilitytoreadEnglishliterature.Besides,whilehisrigorousscholarshipthatIdidnotdarewritinginthepapertheslightestcareless,Iamgratefulhegavemethiswritingopportunity.

Bibliography

[1]AliBashashati1,MehrdadFatourechi1,RababKWard.Asurveyofsignalprocessingalgorithmsinbrain-computerinterfacesbasedonelectricalbrainsignals.JOURNALOFNEURALENGINEERING,2007.

[2]