Early auditory-evoked responses: spectral content.

Spectral analysis of the early auditory-evoked responses in man and in the cat has shown that the predominant contribution to the total power is contained in the band below 50-100 Hz. This low-frequency content is considerably reduced when the corresponding spontaneous brain activity spectrum is subtracted from the response spectrum. Under the latter circumstances, the dominant frequency contribution is found in the 500- to 2,500- Hz bandwidth.