After reading quite a number of papers on pleasure research, (especially those dealing with conditioning rats into feeling pleasure whenever they perform some arbitrary tasks), I notice that a possible confounding variable for these things is the rats own ability to feel pleasure.

Therefore I am curious: Would it possible to disable the brains ability to feel pleasure on its own, while at the same time making so that it can feel pleasure from a stimulating electrode, resulting is a situation where the only way an animal can feel any pleasure at all is through the use of a stimulating electrode?