Diagram explaining results by comparing brain measures to cognitive measures for both age groups and various levels of lifetime exposures (LE).

<p>This diagram uses results from Model B and the left accumbens volume from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091196#pone-0091196-g003" target="_blank">Figure 3B</a> as a guide. Parameters refer to those from equations and models in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091196#pone-0091196-g001" target="_blank">Figure 1</a>. A) Parameter <i>a</i> represents a difference between age groups for the brain measure. Parameter c’ represents a difference between age groups for the cognitive measure. B) The crosses plot the brain and cognitive measures against each other for three levels of LE for both age groups. The parameter <i>q</i> represents the differing relationship between the brain and cognitive measures for the three different LE groups, low middle and high. C) The parameter <i>b</i> represents the overall relationship between the brain and cognitive measures across all levels of LE, i.e. the slope. D) The parameter <i>v</i> represents the differing relationship between the brain and cognitive measures for the three LE groups.