The bandwidth (A) corresponds to the sum in octaves of the frequency range of all the significant peaks in one STRF. The duration (B) is the difference (in ms) between the first and last spike times within the significant area of the STRF. The response strength (C) is the number of spikes in the significant area of the STRF. Values are mean ± SE. *Significant difference with control conditions (P < 0.05, paired t test). Each group of bars corresponds to a different combination of application duration (first number, in minutes) and concentration (second number, in μm). The combinations tested were 4 min/50 μm (three animals, 63 recordings), 4 min/100 μm (two animals, 33 recordings), 20 min/100 μm (five animals, 120 recordings), 100 min/100 μm (one animal, 23 recordings) and 100 min/1000 μm (three animals, 29 recordings). Note that NA reduced the STRF parameters for almost all combinations of concentration and duration of application. A 20 min application at 100 μm gave the most reliable effects.