is uncertainty about how directly it reflects the rewarding value of alcohol's interoceptive effects (see Leeman et al, 2010). If one genotype drinks more alcohol by choice than another, is that because it is more sensitive to ethanol's presumed positive reinforcing value, or is it less sensitive, and therefore needs more alcohol to experience reward? Because animals with unlimited access to alcohol in preference drinking tests rarely achieve blood ethanol levels consistent with behavioral intoxication (Crabbe, 2008), this question is difficult to answer.
