Jean Pierre Flourens
Marie Jean Pierre Flourens (13 April 1794 – 6 December 1867), father of Gustave Flourens, was a French physiologist, the founder of experimental brain science and a pioneer in anesthesia. Through the study of ablations on animals, he was the first to prove that the mind was located in the brain, not the heart.
Eric Knudsen
In 1978, Knudsen and Konishi presented the discovery of an auditory map of space in the midbrain of the barn owl. This discovery was groundbreaking because it unearthed the first non-somatotopic space map in the brain. The map was found in the owl’s midbrain, in the lateral and anterior mesencephalicus lateralis dorsalis (MLD), a structure now referred to as the inferior colliculus. Unlike most sound-localization maps, this map was found to be two-dimensional, with units arranged spatially to represent both the vertical and horizontal location of sound. Knudsen and Konishi discovered that units in this structure respond preferentially to sounds originating in a particular region in space.
In the 1978 paper, elevation and azimuth (location in the horizontal plane) were shown to be the two coordinates of the map. Using a speaker set on a rotatable hemispherical track, Knudsen and Konishi presented owls with auditory stimulus from various locations in space and recorded the resulting neuronal activity. They found that neurons in this part of the MLD were organized according to the location of their receptive field, with azimuth varying along the horizontal plane of the space map and elevation varying vertically. 
Knudsen followed this discovery with research into specific sound localization mechanisms. Two main auditory cues used by the barn owl to localize sound are interaural time difference (ITD) and interaural intensity difference (IID). The owl’s ears are asymmetric, with the right ear’s opening being directed higher than that of the left. This asymmetry allows the barn owl to determine the elevation of a sound by comparing sound levels between its two ears. Interaural time differences provide the owl with information regarding a sound’s azimuth; sound will reach the ear closer to the sound source before reaching the farther ear, and this time difference can be detected and interpreted as an azimuthal direction. At low frequencies, the wavelength of a sound is wider than the owl's facial ruff, and the ruff does not affect detection of azimuth. At high frequencies, the ruff plays a role in reflecting sound for heightened sensitivity to vertical elevation. Therefore, with wide-band noise, containing both high and low frequencies, the owl could use interaural spectrum difference to obtain information about both azimuth and elevation. In 1979, Knudsen and Konishi showed that the barn owl uses interaural spectrum information in sound localization. They presented owls with both wide-bandwidth noise and pure tones. The birds were able to successfully locate pure tones (since they could still gather information from IID and ITD), but their error rate was much lower when localizing wide-bandwidth noise. This indicates that the birds utilize interaural spectrum differences to improve their accuracy.