Examples of the effects of mecamylamine and atropine on high-frequency power. A: normalized power spectra from a mouse under control conditions, after application of mecamylamine and subsequently atropine. Below, mean (line) ± SE (shaded area) 10- to 20-Hz power ratio for each condition; 20, 25 and 25 trials, respectively. Solid and dashed lines indicate power ratios of 0 and 1, respectively. The horizontal bar and light gray shading represent the stimulus, which consisted of fifty 10-ms illuminations at 20 Hz. B: mean ± SE 10- to 20-Hz power ratio for an animal in which atropine was applied before mecamylamine; 50, 40 and 40 trials, respectively. C: mean ± SE 10- to 20-Hz power ratio for an animal in which saline was applied; 50 and 75 trials before and after saline, respectively.