Population rate modulation transfer functions of band-enhanced (left) and band-suppressed (right) inferior colliculus (IC) neurons, respectively, obtained with 3 types of envelopes and defined with a 1.2 criterion. Solid lines: mean; dashed lines: means ± SD computed on logarithmic y-scales. No. of neurons for the band-enhanced type: 38, 24, and 24 for the sine, raised-sine-8, and raised-sine-32 envelopes, respectively; those for the band-suppressed type: 45, 41, and 47.