The biology of self control, part 2

This is a continuation of the post on the physiological origins of self control and criminals. For the first part, click here.

The next neurotransmitter that is important is Serotonin. Serotonin is not capable of crossing the blood-brain barrier, so the brain must produce all that it needs. Serotonin is produced by converting an amino acid called tryptophan into Serotonin. (Serotonin is also used for other purposes in other parts of the body, but that is not within the scope of this post.)

Serotonin is the chemical that causes us to feel loved, safe, and comfortable. This is why meals high in tryptophan are called comfort foods. This is also how the drug Ecstasy (MDMA) works. That drug causes a massive release of Serotonin from your neurons. Long term use of MDMA actually causes a decrease in Serotonin, though, as the cells that produce it begin to "burn out." Various other drugs that are centrally acting also work on Serotonin and its receptors, like SSRIs.

When we do what we know that we are supposed to do, the frontal lobe rewards us with a rush of Serotonin. This is the brain's reward system for good behavior. The Midbrain rewards pleasurable behavior with Dopamine. The balance between the two is the way our behavior is controlled: Midbrain rewards us for pleasure seeking, the Frontal Lobe rewards us for controlling our bad behavior. Most people are fairly balanced between the two, and mostly seek out pleasurable but good behavior.

There are things that can upset this balance:
A mother who exposes her unborn child to alcohol can damage the frontal lobe, and giver birth to a child with impulsive and unsocial behavior. Remember hearing about how the prenatal exposure to alcohol affects the corpus callosum? That's the membrane between the left brain and the right brain that passes information between the two hemispheres of the brain. The corpus callosum of kids with fetal alcohol syndrome is damaged, and in some cases it is absent. This is very similar to what happens when a "normal" person drinks alcohol. After a few drinks, alcohol shuts down the left side of the frontal lobe, which no longer functions the way it should and this suppresses the frontal lobe, causing the person to act on impulse, disregarding consequences, and seek more reward from the Midbrain. A person will act to do things, even  when they know that it is wrong and will cause them trouble in the end. With long term alcohol and drug use, this condition becomes a permanent dysfunction.

Since much of this is biochemical and not conscious thought, people with frontal lobes that are damaged by congenital defects or drug use have no way of stopping this behavior.

That brings us back to recognizing a person's potential for becoming a killer. We can look for people who:
 - chronically use alcohol or drugs,
- have displayed a history of not producing enough Serotonin. They are easy to recognize, as they have problems controlling their impulsive behavior (in other words- criminal records). However, this only is a reliable indicator if the criminal KNEW that what he was doing was wrong. After all, the person must know it is the wrong thing to do, if the frontal lobe is to be expected to control the impulse.
- Identifying others who have problems with their impulse control center. This suggests that there may be a test that can be performed that will indicate a person's proclivity for committing crimes, which may mean that there is a medical solution for some criminals.

You also can see why gun control has little effect. The criminal is a criminal because his brain doesn't stop him from committing acts that he knows are wrong. He knows it is illegal to rob someone, but he doesn't care. He knows as a convicted criminal that it is wrong for him to own a gun, but doesn't care.

On the other side of that, a man convicted of an obscure felony like owning more than 5 sex toys is not a threat to public safety and is unlikely to commit a crime with a firearm, as his impulse control is most probably fully functional.