Auditory frequency selectivity is better for expected than for unexpected sound duration

Previous studies show that insectivorous bats prepare their auditory system to analyze expected returning echoes within a time window to extract target features after pulse emission. These studies suggest that the bat's auditory system must be highly sensitive to signal parameters within this time window. In the current study, we show that most neurons in the central nucleus of the inferior colliculus discharge maximally to a best duration and they have better echo frequency selectivity when the duration of both echo and pulse matches the best duration. This finding complements previous studies that show listeners can better detect a sound when its duration or frequency is expected than unexpected.