Mean response similarity index (cross-correlation value at time-lag zero) between neuronal recordings within primary auditory cortex columns.

<p><b>A–B</b>. Response similarity indices during pure tone exposure. 25-ms (A), and 50-ms (B). <b>C–G</b>. Response similarity indices during white noise burst exposure. 25-ms (C), 50-ms (D) 100-ms (E), 250-ms (F), and 500-ms (G). <b>H–L</b>. Response similarity indices during upward FM sweep exposure. 25-ms (H), 50-ms (I) 100-ms (J), 250-ms (K), and 500-ms (L). <b>M–N</b>. Response similarity indices during con-specific vocalization. Forward (M), time-reversed (N). Note the progressive increase in dissimilarity between responses as a function of acoustic signal duration. Similarity indices varied between ∼0.05 and 1, with an index value of 1 corresponding to comparisons of identical responses (diagonal) and an index value of 0.05 representing the largest discrepancies in response profiles measured. Numbers in color table axes correspond to recording site numbers, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114550#pone-0114550-g001" target="_blank">Fig. 1</a> for electrode site description.