PT - JOURNAL ARTICLE AU - T Takahashi AU - M Konishi TI - Selectivity for interaural time difference in the owl's midbrain AID - 10.1523/JNEUROSCI.06-12-03413.1986 DP - 1986 Dec 01 TA - The Journal of Neuroscience PG - 3413--3422 VI - 6 IP - 12 4099 - http://www.jneurosci.org/content/6/12/3413.short 4100 - http://www.jneurosci.org/content/6/12/3413.full SO - J. Neurosci.1986 Dec 01; 6 AB - The barn owl uses the interaural difference in the timing of sounds to determine the azimuth of the source. When the sound has a wide frequency band, localization is precise. When localizing tones, however, the barn owl errs in a manner that suggests that it is confused by phantom targets. We report a neural equivalent of these phenomena as they are observed in the space-specific neuron of the owl's inferior colliculus. When stimulated with a tone, the space- specific neuron discharges maximally at interaural time differences (ITDs) that differ by one period of the stimulus tone. Changing the stimulus frequency changes the period of the ITD-response functions, but 1 ITD evokes, in most neurons, a maximal response, regardless of frequency. This ITD is the characteristic delay (CD). When stimulated with noise, there is a maximal response only to ITDs at or near the CD. Thus, the space-specific neuron can unambiguously signal the CD, provided that the signal contains more than 1 frequency. The preferential response to a single ITD, which is observed with noise stimuli, was also observed when the summed waveform of the best frequency and another tone, F2, was presented. The response of the space-specific neuron to these 2-tone stimuli could not be accounted for by the summing or averaging of the ITD-response functions obtained with the best frequency or F2 alone, suggesting that nonlinear neural processes are involved.