Results
In the present study, we focused on putative effects of TRAP on the default mode network (DMN), a set of inter-connected cortical brain regions in which activity is maximal at rest or during internal thought engagement. We focused on the DMN, given the preferential vulnerability of this network to aging [The 25 participants were 11 female and 14 male, with mean age of 27.4 (s.d. 5.5) years. Exposure conditions were achieved as follows, in terms of PMIn the DE group, there were no significant differences in DMN functional connectivity for post- compared to pre-DE exposure (Fig. 
Results of group level comparisons (
Functional connectivity post- and pre-filtered air exposureBrain regions showing increased functional connectivity in the post-filtered air condition relative to the pre-filtered air condition (min Z > 2.3; cluster significance: There were small albeit significant differences observed when comparing groups pre-exposure. Specifically, participants demonstrated greater functional connectivity, pre-DE compared to pre-FA, in the right occipital fusiform gyrus as well as the occipital pole (Fig. 
Functional connectivity pre-diesel exhaust exposure and pre-filtered air exposureBrain regions showing increased functional connectivity in the pre-diesel exhaust condition relative to the pre-filtered air condition (min Z > 2.3; cluster significance: 
Functional connectivity post-diesel exhaust exposure and post-filtered air exposureBrain regions showing increased functional connectivity in the post-filtered air condition relative to the post-diesel exhaust condition (min Z > 2.3; cluster significance: 