Joint response to two effectors in the four suppositions resulting from combining the two implicit key conditions of the IA hypothesis (see text).

<p>In the first column, dots are the result of simulations and surfaces the respective fittings to the model (26). Isobolograms, correlations between observations and predictions and parametric variations (<i>K</i>_i: ○, <i>m</i>_i: •) of the response to an effector as a function of the dose of the another are added. D₁ and D₂: doses; R: response. Numerical data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061391#pone-0061391-t004" target="_blank">Table 4</a>.