According to this thread, certain regions of the brain, and even some distributed activation patterns can be up/down regulated via bio-feedback.
Is it possible in theory and is there any research where subjects were taught to consciously control neurotransmitter (e.g. serotonin, dopamine, etc...) levels?
It seems that doing so would present with alternatives to pharmacological methods of altering neurotransmitter levels in treatment of various mood and cognitive disorders.
Firstly, you wouldn't be directly controlling neurotransmitter. From the human perspective, you'd be controlling higher-level events (and they aren't necessarily describable on more than a phenomenological level). Of course, this would also lead to some changes in neurotransmitter release, but in a complex way: that's all handled at a lower level by the cells.
That being said, neurofeedback is a (the?) clinical practice that most closely matches your question. If you look at the references in the wiki page I linked, you will see lots of papers reporting on the findings and techniques. I do not know the current state of the research.
Turns out this is possible with microdialysis. Microdialysis uses small probes that can continuously sample the concentrations of target compounds (i.e. neurotransmitters when embedded in a brain).
In theory, though somewhat invasively, one could insert a few of these probes in a person's brain, display the neurotransmitter concentrations on a computer screen, and train the subject to change the neurotransmitter concentrations through his/her thoughts as they would in a bio-feedback setup.
If the concentrations are associated with some neurological disease (i.e. depression, anxiety, schizophrenia), the subject could learn to alter their neurotransmitter levels, and possibly reduce their symptoms, without the use of pharmacological interventions and their associated side-effects.
