Pitchisoneofthemostimportantauditoryperceptioncharacteristicsofsound;however,themechanismunderlyingthepitchperceptionofsoundisunclear.Althoughtheoreticalresearcheshavesuggestedthatperceptionofvirtualpitchisconnectedwithphysicsincochleaofinnerear,thereisnodirectexperimentalobservationofvirtualpitchprocessinginthecochlea.Bylaserinterferometry,weobserveshiftphenomenaofvirtualpitchinbasilarmembranevibrationofexsomatizedcochlea,whichisconsistentwithperceptualpitchshiftobservedinpsychoacousticexperiments.Thismeansthatthecomplexmechanicalvibrationofbasilarmembraneincochleaplaysanimportantroleinpitchinformationprocessingduringhearing.
