Anger and Serotonin

My buddy Jamie Scott is a research machine.  It's all I can do to keep up with the interesting papers and links he emails my direction.  Today's article is yet another one we owe to his sharp eye.  He also has brand new digs at a wordpress blog (*brief moment of jealousy*) - so edit/add him to your blogroll and check it out:

That Paleo Guy

Some music - I rather adore the Yeah Yeah Yeahs.  Here's an oldie but a goodie:  Gold Lion (right click to open in new tab).  Favorite comment on youtube:  "i think I just got whiplash rocking out to this song" [sic].

Want something a bit more classical?  How about a Chopin Nocturne played by none other than Rachmaninoff from 1927?  (You will not be rocking out, but it is quite lovely).

The paper is in Biological Psychiatry: Effects of Acute Tryptophan Depletion on Prefrontal-Amygdala Connectivity While Viewing Facial Signals of

Aggression

It's kinda cool.  Involves humans, which is always a plus.  It is one of those "view angry faces whilst in a functional MRI machine" which has some limitations, but it is pretty much the only way to see what's going on in real time in the old noggin, seeing as how it's rather awkward to test gene expression and neurotransmitter levels other ways without decapitation (not likely to pass the institutional review board any time soon, unless you were unfortunate enough to be born as a research rodent).  (Random aside - Andrew tweeted this REAL MIND READING finding yesterday.  Wow.) 

How many segues is that?  Welcome to my left-handed, small child-raising brain.  As we know, depletions in serotonin, especially in a particular communication circuit between the frontal lobes (the policeman) and the amygdala (the emotional/rage center of the brain) leads to anger and aggressive behaviors.  Now, there are some people who are just aggressive altogether - I'm thinking Drew Barrymore's boyfriend in one of the Charlie's Angels movies.  We're not talking about that.  We're talking about impulsive aggression.  All the sudden, you just want to jump out of your car and strangle the other driver who cut you off (please don't do this).  Impulsive aggression can be unexpected and very scary, and can certainly ruin lives.  

So what if it happens just because you forgot to eat your banana this morning???  Oh, don't worry, we are likely more resilient than all that… but in an experimental setting, one can pretty much abolish serotonin via a weird laboratory tryptophan-depleting drink.  Then you get into an MRI machine.  Then you look at pictures of angry faces (if I were running this experiment, I would pipe in some hard core metal, and not one of Chopin's Nocturnes).  Of course, I read A Clockwork Orange in high school.  The tryptophan-depleting drink significantly reduced both plasma tryptophan levels (remember, tryptophan is the precursor to serotonin) and the ratio of tryptophan to other long-chain neutral amino acids  (remember, tryptophan competes with these other amino acids for entrance into the brain).  

In the end, the reactions of the tryptophan-depleted individuals to the angry faces vs. controls was statistically significant.  Tryptophan-depleted folks had a higher response to the angry faces within the amygdala (the rage/anger part of the brain) compared to controls, and compared to the response to neutral faces.  These findings would suggest that, as suspected, serotonin helps you chill out and assess the situation when faced with an angry hoarde.  

Between the mind reading and the availability of a rapid acting tryptophan-depleting anger drink that will affect our aggressive reactions, I'm a little worried about the future of our free will.  But I'll try to eat some protein, micronutrients, a banana, and put my trust in the incompetence of bureaucracy in order to be less paranoid.