Efferent fibers from contralateral brainstem go to outer hair cells. These fibers liberate Acetycholine transmitter on to HC’s.

• Efferent fibers from contralateral brainstem go to outer hair cells. These fibers liberate Acetycholine transmitter on to HC’s.
• Activity of efferent fibers cause elongation of outer hair cells lifting the tectorial mbr off from the inner row of hair cells.
• This removes the tectorial membrane contact with the inner row of hair cells over a specific frequency range.
• Efferent Activity on outer hair cells is removed by 0.6 mm distance for the higher or the lower frequencies. This focuses the frequency detection.