2015 Hearing & Balance


  • adaptation is the decrease in receptor potential in response to a constant stimulus (recall more detailed explanation from sensory physiology lecture)

  • common to many sensory systems
    • auditory hair cells exhibit extremely rapid adaptation
    • vestibular hair cells (esp. in saccule and utricle) exhibit little to no adaptation

  • adaptation motor continuously moves up the actin core of the tallest stereocilium, maintaining tension on the tiplink
    • motor complex is thought to involve myosin 7A, a protein only found in the inner ear and implicated in one form of hereditary deafness

  • also defines a set point for the system, so that some transduction channels are always open, causing slight depolarization of the hair cell and basal release of neurotransmitter – this allows negative displacements to reduce auditory nerve firing
Adaptation motor
Email: Dr. Janet Fitzakerley | ©2015 University of Minnesota Medical School Duluth | Last modified: 24-jan-15 5:16 PM