Editing Tonotopy (section)

== History ==

The earliest evidence for tonotopic organization in auditory cortex was indicated by Vladimir E. Larionov in an 1899 paper entitled "On the musical centers of the brain", which suggested that lesions in an S-shaped trajectory resulted in failure to respond to tones of different frequencies.<ref>{{cite book |title=Comparative Studies of Hearing in Vertebrates |last1 = Popper |first1 =  Arthur N |last2 = Fay |first2 =  Richard R |name-list-style = vanc |isbn=978-1461380740 |location=New York, NY |oclc=1058153919 |date=2012-12-06}}</ref>  By the 1920s, cochlear anatomy had been described and the concept of tonotopicity had been introduced.<ref>{{Cite journal| vauthors = Stevens SS |date= September 1972 |title=Georg von Békésy|journal=Physics Today|language=en|volume=25|issue=9|pages=78–81|doi=10.1063/1.3071029 |bibcode=1972PhT....25i..78S}}</ref> At this time, Hungarian biophysicist, [[Georg von Békésy]] began further exploration of tonotopy in the auditory cortex.  Békésy measured the cochlear traveling wave by opening up the cochlea widely and using a strobe light and microscope to visually observe the motion on a wide variety of animals including guinea pig, chicken, mouse, rat, cow, elephant, and human temporal bone.<ref>{{Cite book|title=Experiments in hearing. | first1 = Georg | last1 = von Békésy | first2 = Ernest Glen | last2 = Wever | name-list-style = vanc |date=1960|publisher=McGraw-Hill|others=Wever, Ernest Glen, 1902-|isbn=978-0070043244|location=New York|oclc=14607524}}</ref>  Importantly, Békésy found that different sound frequencies caused maximum wave amplitudes to occur at different places along the [[basilar membrane]] along the coil of the cochlea, which is the fundamental principle of tonotopy. Békésy was awarded the  Nobel Prize in Physiology or Medicine  for his work.

In 1946, the first live demonstration of tonotopic organization in auditory cortex occurred at Johns Hopkins Hospital.<ref name="pmid20280876">{{cite journal | vauthors = Walzl EM, Woolsey CN | title = Effects of cochlear lesions on click responses in the auditory cortex of the cat | journal = Bulletin of the Johns Hopkins Hospital | volume = 79 | issue = 4 | pages = 309–19 | date = October 1946 | pmid = 20280876 }}</ref> More recently, advances in technology have allowed researchers to map the tonotopic organization in healthy human subjects using [[Electroencephalography|electroencephalographic]] (EEG) and [[Magnetoencephalography|magnetoencephalographic]] (MEG) data.  While most human studies agree on the existence of a tonotopic gradient map in which low frequencies are represented laterally and high frequencies are represented medially around [[Heschl's gyrus]], a more detailed map in human auditory cortex is not yet firmly established due to methodological limitations<ref>{{cite journal | vauthors = Langers DR, van Dijk P | title = Mapping the tonotopic organization in human auditory cortex with minimally salient acoustic stimulation | journal = Cerebral Cortex | volume = 22 | issue = 9 | pages = 2024–38 | date = September 2012 | pmid = 21980020 | pmc = 3412441 | doi = 10.1093/cercor/bhr282 }}</ref>