These findings, suggesting the LR status may relate to differential brain processing across placebo (or non-drinking) and alcohol conditions, were supported by data from 49 high/low matched pairs while performing a stop signal task [20]. Despite similar task performance, the low LR group again evidenced more BOLD response contrast after placebo, but the after-alcohol low LR subjects had lower while higher LR subjects had greater contrast. For these non-alcoholic subjects, LR group by placebo/alcohol condition interactions were most prominent in posterior brain regions that might reflect perception of auditory and visual stimuli, not in the more frontal regions more likely to reflect disinhibition. Finally, an additional analysis revealed that low LR subjects had significantly less increase in cerebral blood flow after alcohol than those with higher LR [21].
