Since orexin injections into the LDT and LC suppress REM sleep, and knockdown of OX1 in LC increases REM during the dark phase (Chen et al., 2010) it is plausible that remaining OX1-excitation in LDT, LC, and perhaps DR, reduces cataplexy in OX−/−2 mice. This evidence concerns the gene HCRT and Cataplexy.