Indeed, DE probesets were distinct for the brain regions (see Fig 1) and within each brain region overlap of DE probesets across time was limited (see S1 Fig). Within each brain region the mRNA response to CIE also produced a fairly unique profile of DE genes at each time point. This emphasizes the unique time- and brain-region specific alterations that occur following CIE vapor. Notably, the temporal patterns of microRNA and mRNA expression patterns differed (see Fig 2). All brain regions exhibited a decrease in DE microRNAs from 0 to 8h and a concomitant reduction of DE mRNAs between 8 and 120h, likely reflecting the time required for the microRNAs to exert their effects on gene targets. These findings are consistent with those identified in previous studies in mouse [7] and human alcoholics [10] which demonstrate over-represented directional changes based on time of alcohol exposure. In contrast to AMY and NAC, the number of DE microRNAs at 120h continued to decline in the PFC, perhaps indicating that microRNA regulation in the PFC is under greater homeostatic regulatory control given the
