How Ear Hairs Stick Together

  • Published26 Mar 2020
  • Author Charlie Wood
  • Source BrainFacts/SfN

Waves of sound fill the world. Your ears translate these waves into ripples in the fluid that washes over these structures within your ears’ hair cells called stereocilia — sitting atop sensory hair cells in the ear. They bundle together, arranged in rows of varying heights like organ pipes. Some bundles flex for higher notes while other bundles flex for lower notes.

Over the last two decades, researchers have discovered that this flexing pulls on thin threads known as “tip links,” that connect the tops of lower rows of stereocilia to the sides of the taller upper rows. The tip links bind one row to the next, stiffening the bundle, so they all sway together. They also attach directly to gated channels that pull open as the group sways, letting molecules rush through into the hair cells to set off an electrical signal in the connecting nerve that your brain hears as sound. Damaging tip links — by blasting them with loud sounds, for instance, can affect the swaying of the whole bundle. Stereocilia that are not connected by tip links can cause deafness or may trigger ringing of the ears, tinnitus.

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BrainFacts/SfN

Kachar, B., Parakkal, M., Kurc, M., Zhao, Y.-D., & Gillespie, P. G. (2000). High-resolution structure of hair-cell tip links. Proceedings of the National Academy of Sciences, 97(24), 13336–13341. doi: 10.1073/pnas.97.24.13336

Kurian, R., Krupp, N. L., & Saunders, J. C. (2003). Tip link loss and recovery on chick short hair cells following intense exposure to sound. Hearing Research, 181(1-2), 40–50. doi: 10.1016/s0378-5955(03)00165-5

Sakaguchi, H., Tokita, J., Müller, U., & Kachar, B. (2009). Tip links in hair cells: molecular composition and role in hearing loss. Current Opinion in Otolaryngology & Head and Neck Surgery, 17(5), 388–393. doi: 10.1097/moo.0b013e3283303472

Saunders, J. C. (2007). The role of central nervous system plasticity in tinnitus. Journal of Communication Disorders, 40(4), 313–334. doi: 10.1016/j.jcomdis.2007.03.006