Interaural time difference is an important cue
for sound localization. In the barn owl (Tyto alba) neuronal
sensitivity to this disparity originates in the brainstem nucleus
laminaris, Afferents from the ipsilateral and contralateral
magnocellular cochlear nuclei enter the nucleus laminaris
through its dorsal and ventral surfaces, respectively, and
interdigitate in the nucleus. Intracellular recordings from these
afferents show orderly changes in conduction delay with depth
in the nucleus. These changes are comparable to the range of
interaural time differences available to the owl. Thus, these
afferent axons act as delay lines and provide anatomical and
physiological bases for a neuronal map of interaural time
differences in the nucleus laminaris.