简介：FragileXsyndromeisthemostcommonformofinheritedmentalretardationaffectingupto1in4000individuals.ThesyndromeisinducedbyamutationintheFMR1gene,causingadeficiencyinitsgeneby-productFMRP.ImpairmentinthenormalfunctioningofFMRPleadstolearningandmemorydeficitsandheightenedsensitivitytosensorystimuli,includingsound(hyperacusis).ThemolecularbasisoffragileXsyndromeisthoroughlyunderstood;however,theneuralmechanismsunderlyinghyperacusishavenotyetbeendetermined.Astheinferiorcolliculus(IC)istheprincipalmidbrainnucleusoftheauditorypathway,thecurrentstudyaddressesthequestionsunderlyingtheneuralmechanismofhyperacusiswithintheICoffragileXmice.AcuteexperimentswereperformedinwhichelectrophysiologicalrecordingsoftheICinFMR1-KOandWTmiceweremeasured.ResultsshowedthatQ-valuesforWTweresignificantlylargerthanthatofFMR-1KOmice,indicatingthatWTmiceexhibitsharpertuningcurvesthanFMR1-KOmice.WealsofoundtheratioofthemonotonicneuronsintheKOmicewasmuchhigherthantheWTmice.TheseresultssuggestthatlackofFMRPintheauditorysystemaffectsthedevelopmentalmaturationandfunctionofstructureswithintheauditorypathway,andinthiscasespecificallytheIC.ThedysfunctionobservedwithintheauditoryneuralpathwayandinparticulartheICmayberelatedtotheincreasedsusceptibilitytosoundasseeninindividualswithfragileXsyndrome.OurstudymayhelponunderstandingthemechanismsofthefragileXsyndromeandhyperacusis.