The Central Code of Hearing

Abstract

As one ascends in the auditory pathway, the locking of neural discharges to the phases of the vibration of the stimulating sound becomes less and less precise. Moreover the ‘volleying’ of neurons in third- and higher-order neurons in the auditory nuclei of the brain stem, seems to be optimal during relaxed inattentiveness of the subject and to become less strict when the animal is alerted to the sound stimulus. Spatial information related to the maximal vibration of various wavelengths in the basilar membrane of the cochlea is better preserved, but it too is badly obscured at the cortical level. Many data support the notion that simple pitch discrimination is a function of the brain stem, whereas the auditory cortex is concerned with more sophisticated aspects such as the complexity of tones and with their temporal variations.