Response areas of synchronized discharges measured at different values of modulation rates were studied in inferior colliculus of bats (Rhinolophus ferrumequinum). Single neurons showed a variety of synchronized response areas to sinusoidally amplitude-modulated stimuli (thresholds of synchronized discharge plotted versus modulation rates, carrier frequency and modulation depth are constant). All neurons showed best modulation frequency where minimal thresholds could be obtained. Synchronized response areas measured in collicular units were sharply or widely tuned, some showed upper thresholds, tuning curves were symmetrical or asymmetrical. The data suggest that response features of studied units prove to be well suited for processing echoes produced by wing beats of flying insects.