there's a sense in which humans don't have values, just things like thoughts and behaviors.

Between values, thoughts, and behaviors, it seems like the larger gap is between behaviors on the one hand, and thoughts and values on the other. Given a neurological description of a human being, locating "thoughts" in that description would seem roughly comparable in difficulty to locating "values" therein. Not that I take this to show there are neither thoughts nor values. Such a conclusion would likely indicate overly narrow definitions of a thought and a value.

I could see neuroscience results arguing for one side or the other, but I think the question of what exact neuroscience results would argue for which answer is a morally loaded one.

I think so too.