Detectability of Features from Neuronal Responses to Natural Images and Random Stimuli

<div><p>(A) Probability distribution of feature contrast in a natural ensemble (or, equivalently, its matched random ensemble). For simplicity, only the positive side (feature contrast >0) is shown. Gray shading: feature contrasts near zero (<<i>T</i>₀, here <i>T</i>₀<i>=</i> 0.007, “feature absent”); black shading: high feature contrasts (><i>T</i>₁, here <i>T</i>₁ = 0.04, “feature present”).</p> <p>(B) Conditional probability distributions of responses evoked by natural images (upper) and random stimuli (lower). Solid lines: response distributions when the feature was present in stimulus (black shading in [A]); dashed lines: distributions when the feature was absent (gray shading in [A]).</p> <p>(C) Feature detectability in natural images versus that in matched random stimuli, for the same population of cells shown in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0030342#pbio-0030342-g003" target="_blank">Figure 3</a>B. Detectability was measured as the percentage of trials in which stimuli were correctly classified as “feature present” or “feature absent” (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0030342#s4" target="_blank">Materials and Methods</a>).</p>