PAST INVESTIGATIONS have shown that the auditory spectrum has a spatial representation within the cochlea.1 The low frequencies have their most effective action on the structures in the apical turn and the high frequencies on those structures in the basal turn of the cochlea.
Although these general facts are well known, there is incomplete information regarding the effect of frequency and intensity on the location and spread of sensory and neural excitation within the cochlea.
One method of studying the problem is to produce restricted lesions in the cochlea and to determine the effect on auditory function. The method also provides information on the pathology of perception deafness. We have performed a series of such experiments on cats which were conditioned for auditory testing.
In one series of animals2 a lesion was made in the apex of the cochlea by introducing a small needle through the bony wall.