Time course of gene expression profiles. The figure shows the summary plots of expression profiles of selected genes, in three different experimental conditions, at 5, 15, 30 and 60 minutes after treatment. The expression level is the Log2 Fold Change ratio relative to the untreated condition. Each subplot is composed by three lines: the average expression value for the genes written on the left (red), average – standard deviation (dotted green), average + standard deviation (dotted blue). Every frame corresponds to a different cluster of genes and is composed by three plots: the response to 10 ng/ml NGF (left), the response to 20 ng/ml proNGF (center), the response to a mixture of 10 ng/ml NGF + 20 ng/ml proNGF (right). To evaluate the similarity between the responses to the three treatments the “centered Pearson” correlation coefficients (NGF, proNGF), (NGF, mixture), (proNGF, mixture) have been computed for each gene expression profile. The colours of the small rectangles below each plot indicate the similarity between the responses within each cluster, based on the correlation coefficients (where coefficients > 60% the profiles are considered similar): orange = NGF-like profile, blue = proNGF-like profile, green = mixture-like profile, grey = almost no response. The notes on the right summarize the response to the mixture of 10 ng/ml NGF + 20 ng/ml proNGF.