The article says that it was already known that that area of the medulla was responsible for sleep paralysis during REM. Perhaps they just looked to see if act

The article says that it was already known that that area of the medulla was responsible for sleep paralysis during REM. Perhaps they just looked to see if activating it causes sleep paralysis, which is what would be expected. If that were true, then deactivating it could be a potential area to explore for treatment of certain REM disorders (such as sleep paralysis failing to occur, and the person acts out their dreams). Instead, they found that activating it causes both sleep paralysis and REM itself, all together. This is actually discouraging from the standpoint of treatment of REM disorders. However, it is still very interesting to know that REM can be caused by that area.