Time and intensity cues are processed independently in the auditory system of the owl

Space-specific neurons, found in the barn owl's inferior colliculus, respond selectively to a narrow range of interaural time and intensity differences. We show that injecting a local anesthetic into one cochlear nucleus, nucleus magnocellularis, alters the space-specific cell's selectivity for interaural time difference, leaving its selectivity for interaural intensity difference intact. Anesthetizing the other cochlear nucleus, nucleus angularis, has the converse effects. We show also that the space-specific neuron's selectivity for one interaural cue is the same for all effective values of the other cue. We conclude that time and intensity cues are processed in separate neural channels of the barn owl's auditory system and that the two cues operate independently.