Fig. 7.

Receiver operating characteristic (ROC) analysis in a sample neuron. A: speed-tuning curve of the neuron (data points and the solid line) measured with a stimulus covering the receptive field (16° ø). The gray arrow indicates the speed at the point with the highest slope in the ascending portion of the tuning curve. The black arrow marks the preferred speed of the neuron. B: firing-rate histograms of the same neuron for the largest (16° ø) and smallest (4° ø) stimulus (black and gray, respectively). C: ROC curve computed from the two distributions in B. The area under the ROC curve (AUC) for this neuron is larger than 0.5, indicating that the two distributions in B are separate and that the firing rates for a smaller stimulus are higher than for a larger stimulus.