Population data showing the percentage of neurons that fell into different categories of bandwidth change of FLRF. BW10, BW20, and BW30 are the FLRF bandwidth at 10 dB, 20 dB, and 30 dB above MT, respectively. The changes of bandwidth were assigned into three categories: narrowed, widened, and unchanged. Row 1 shows the data of 28 neurons whose FLRFs were determined at five levels of masker conditions, and row 2 shows data of 14 neurons whose FLRFs were determined at four level of masker conditions. The relationships among different masker levels are the following: a < b < c < d < e; a’ < b’ < c’ < d’.