Contusion injury causes profound and robust decrease in linear ventilatory pattern variability. A) Contused animals (pink) show minimal deficit in weight compared to sham controls (purple) up to twelve weeks following trauma and weight gain compared to baseline (BL). B) Contusion (light grey) and sham (tungsten) injury do not cause an increase in nonlinear variability shown through the nonlinear complexity index (NLCI) However, C) Mutual Information, and D) Sample Entropy of i) the original and ii) surrogate data sets following pre-trauma baseline (BL), C3 contusion injury (light green/orange), and sham control (dark green/red). Graphs show means ± SEM, Comparisons between BL and contusion * = p < 0.05, ** = p < 0.01; *** = p < 0.001; contusion and sham * = p < 0.05. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)