Short-latency auditory responses obtained by cross correlation.
Short-latency auditory responses were derived by cross correlation of pseudorandom white noise with averaged scalp potentials in guinea pigs. The cross-correlation functions were characterized by distinct cochlear microphonic and neural components, as distinguished by susceptibility to hypothermia and masking noise. This technique detects only linear, frequency-following responses of the auditory system, and demonstrated neural frequency following up to 3-4 kHz; thresholds were about 30-40 dB spectrum level. While conventional auditory brain stem responses reflect onset neural activity and are most responsive to high-frequency stimuli, cross-correlation responses reflect frequency-following activity, primarily to low frequencies, and thus may represent a complementary method of electrophysiologic assessment of the auditory system. Data are very rapidly acquired, and estimation of responses of limited areas of the cochlea may be possible by off-line digital filtering of cross-correlation functions obtained with broadband noise stimuli.
D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory; D006168:Guinea Pigs; D008144:Loudness Perception / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology; D010898:Pitch Perception / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*