▁memb rane ▁velocity ▁▁ ▁[ 2 . 6 ] ▁Dem on str ation ▁that ▁in ▁the ▁absence ▁of ▁outer ▁hair ▁cells ▁there ▁is ▁a ▁significant ▁threshold ▁shift , ▁change ▁in ▁frequency ▁select ivity , ▁and ▁linear ization ▁of ▁the ▁co ch lea . ▁ ▁This ▁experimental ▁series ▁forms ▁the ▁basis ▁of ▁much ▁of ▁our ▁current ▁concepts ▁of ▁co ch lear ▁function , ▁not ably ▁ 5 0 - 6 0   d B ▁ampl ification ▁by ▁outer ▁hair ▁cells ▁▁ ▁[ 2 . 7 ] ▁First ▁int rac ell ular ▁record ings ▁from ▁outer ▁hair ▁cells ▁in ▁v ivo ; ▁first ▁int rac ell ular ▁record ings ▁from ▁hair ▁cells ▁in ▁the ▁low - fre quency ▁regions ▁of ▁the ▁co ch lea ▁▁ ▁[ 2 . 8 ] ▁First ▁record ings ▁from ▁aud itory ▁n erve ▁terminal s ▁in ▁v ivo ▁ ▁[ 2 . 9 ] ▁Ex perimental ▁series ▁establish ing ▁many ▁properties ▁of ▁elect rom ot ility ▁of ▁isolated ▁outer ▁hair ▁cells , ▁including ▁the ▁proof ▁that ▁s tere oc ilia ▁disp lacement ▁produces ▁outer ▁hair ▁cell ▁mot ility ▁ ▁[ 2 . 1 0 ] ▁In vention ▁and ▁development ▁of ▁the ▁hem ico ch lea ▁technique ▁and ▁int rac ell ular ▁record ings ▁from ▁hair ▁cells ▁in ▁the ▁hem ico ch lea ▁under ▁bas ilar ▁memb rane ▁stim ulation ▁▁▁ ▁[ 2 . 1 1 ] ▁Disc overy ▁that ▁outer ▁hair ▁cell ▁ax ial ▁st iff ness ▁is ▁voltage ▁dependent ▁ ▁[ 2 . 1 2 ] ▁Disc overy ▁and