User:Rattyray/sandbox

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. By the 1920s, cochlear cochlear anatomy had been described and the concept of tonotopicity had been introduced. 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. 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 principal 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 John Hopkins Hospital. More recently, advances in technology have allowed researchers to map the tonotopic organization in healthy human subjects using electroencephalographic (EEG) and 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.