Editing Tonotopy (section)

==== Structural organization ====

In the [[cochlea]], sound creates a traveling [[wave]] that moves from base to apex, increasing in amplitude as it moves along a tonotopic axis in the [[basilar membrane]] (BM).<ref name=":2">{{Citation|last=Dallos|first=Peter|chapter=Overview: Cochlear Neurobiology|date=1996|pages=1–43|editor-last=Dallos|editor-first=Peter| name-list-style = vanc |series=Springer Handbook of Auditory Research|publisher=Springer New York|language=en|doi=10.1007/978-1-4612-0757-3_1|isbn=9781461207573|editor2-last=Popper|editor2-first=Arthur N.|editor3-last=Fay|editor3-first=Richard R.|title=The Cochlea|volume=8}}</ref> This pressure wave travels along the BM of the cochlea until it reaches an area that corresponds to its maximum vibration frequency; this is then coded as pitch.<ref name=":2" /> High frequency sounds stimulate neurons at the base of the structure and lower frequency sounds stimulate neurons at the apex.<ref name=":2" /> This represents cochlear tonotopic organization. This occurs because the mechanical properties of the BM are graded along a tonotopic axis; this conveys distinct frequencies to hair cells (mechanosensory cells that amplify cochlear vibrations and send auditory information to the brain), establishing receptor potentials and, consequently frequency tuning.<ref name=":2" /> For example, the BM increases in stiffness towards its base.