Extraction of preferred and nonpreferred stimulus features by central electrosensory neurons. (A) Spike-triggered average amplitude and phase from an AM-sensitive ELL neuron, PM-sensitive ELL neuron, and AM-sensitive torus neuron during separate and simultaneous random AM and random PM. (B) Areas under the ROC curve (mean ± sem) for AM and PM feature extraction from AM-sensitive and PM-sensitive ELL neurons during separate and simultaneous random AM and random PM. Significant differences, as determined by a Wilcoxon matched-pairs test, are noted by asterisks (*p < 0.05, **p < 0.01, ***p < 0.000001).