Auditory between-channel processing by measuring across-ear temporal gap detection

The aim of this study is to examine the hypothesis that auditory gap detection performance is impoverished by a temporal comparison of activity in different perceptual channels. We conducted an across-ear temporal gap detection task, where the leading and trailing markers delimiting a gap were presented to separate ears, which are regarded as independent channels at least up to the superior olivary complex in the auditory brainstem. Results showed that across-ear gap detection thresholds increase gradually as the frequency difference between the two sinusoidal markers was increased to above an octave. Furthermore, the patterns of the across-ear gap detection thresholds were roughly correlated with those of the monaural gap detection thresholds except when the leading and trailing markers were identical in frequency. Consequently, it was suggested that the gradually impoverished gap detection performance would reflect between-channel processing in the central auditory system at least above the superior olivary complex.