The thing is, every one of your impulses comes with a goal of receiving a positive feedback. Accomplish goal, get serotonin or dopamine. Body tells you to have sex, it doesn't matter if your judgement suggests otherwise, you're going to have sex or the next generation will be made of children from hornier parents. Everything works this way. The danger of cyber drug technology is that we will have the power to cut out the middle step. Just get the positive reward of orgasm and skip the sex. Take full control... except for the control to not need the serotonin and dopamine.
I think that it is my rationality, which I give full authority to in my mind, that counters this effect. Rational problem solving circuits of my brain get a reward for solving puzzles and connecting dots. They have a positive feedback loop to keep doing more but they also get the positive feedback just for working honestly. I get a headache and emotional withdraw if I find myself lying, even to others. I hate liars, and to lie myself means I would hate myself.
Therefore, I think if one part of my rational neurons got a positive feedback that didn't mesh with consistency, the others would figure it out and say "No! We do not lie!" It's of course more complex than that and there are some exceptions like playing pretend or doing so to prevent others from harm... ok, yes, also to save face at times, but we hate ourselves for that. :(