Sources of averaged neural responses recorded in animal and human subjects during cochlear audiometry (Electro-Cochleogram)

The five waves comprising the averaged neural response (cochlear audiometry or electrocochleogram) to click acoustic stimuli were recorded with pinna and scalp electrodes in both human and animal subjects. The latencies and waveform of the waves in the cat were similar to those recorded in human subjects. Recordings in the cat with pinna-scalp electrodes simultaneously with intracranial recordings from auditory nuclei in the same animal, lead to the following conclusions concerning the sources of these waves in cats and probably in man also: 1. the first response wave is generated by the first order cochlear nerve fibers; 2. the second wave is generated mainly in the cochlear nucleus; 3. the third wave is generated in the superior olivary complex; 4. the fourth and fifth waves are generated in the inferior colliculus. Thus, this recording system provides a convenient means of measuring the neural activity of the cochlea, the brain stem auditory nuclei and the cerebral cortex in human subjects.