<prompt> Cochlear microphonic potentials exhibitsProduced by outer hair cellsProduced by inner hair cellsElectrodes have to be inserted over round windowSurface electrodes can not measure it  <response>: i.e. Produced by outer hair cells:COCHLEAR MICROPHONIC CM - when basilar membrane moves in response to sound stimulus, electrical resistance at the tip of hair cells changes allowing flow of K through hair cells and produces voltage fluctuations called cochlear microphonic. It is an alternating current AC potentialsElectrical Potentials of Cochlea and CN VIIIFROM COCHLEA1. Endocochear potentials - It is direct current DC potential recorded from scala media. It is 80 mV and is generated from the stria vascularis by Na K ATPase pump and provides source of energy for cochlear transduction. It is present at rest and does not require sound stimulus. This potential provides a sort of battery to drive the current through hair cells when they move in response to a sound stimulus.2. Cochlear microphonic CM3. Summating potentials SP - It is a DC potential and follows envelop of stimulating sound It is produced by hair cells. It may be negative or positive. SP has been used in diagnosis of Menieres disease. It is superimposed on VIII nerve lesionsFROM NERVE FIBRERS CN VIII4. Compound action potential - It is an all or none response of auditory nerve fibresBoth CM and SP are receptor potentials as seen in other sensory end organs - The differ from action potentials in thata They are graded rather than all or none phenomenonb Have no latencyc Are not propagatedd Have no post response refractory period 