Not A Blog™

[…continued from Wednesday]

There are two important differences in the way extroverts’ and introverts’ brains work. The first is where information is processed, as seen by blood flow via PET scans. The extrovert process most information in the temporal lobe and motor area, the structures associated with receiving and processing incoming stimuli from the senses. The introvert does most of the processing in the frontal lobe and other structures related to memory, imagination and reasoning. In short: extroverts live in the world; introverts live in their head.

The specifics are hilarious because they explain so much, but if this is too technical, skip down a few paragraphs. The first three steps are the same in both extro- and introverts: spinal cord to hypothalamus to thalamus. The thalamus is where the split happens: anterior in introverts as a jumping off point to the frontal structures; posterior in extroverts in order to send increased stimuli to the amygdala. The amygdala handles emotional response to stimuli. This is important. The extrovert is associating emotions with information as soon as it is obtained.

In the introvert, the stimuli goes to the anterior thalamus then to broca’s area! Broca’s area controls—get this—internal monologues. Which is amazing because, like I said yesterday, I have essentially a non-stop internal monologue going in my head. Every situation, every possible conversation route; I imagine it all. If I’ve met you, I have a miniature version of you in my head which I talk to. I talk to myself. And now it makes sense: because every bit of stimulation I receive uncontrollably sets off a cascade of internal monologues. It’s the first stop after the necessary stuff.

Continuing, in extroverts, the signal goes from the emotional center of the amygdala to the temporal and motor centers where it’s acted on, if necessary—which, in turn, release certain neurotransmitters, that I’ll be discussing shortly. In introverts, the signal goes from broca’s area to the frontal lobe and the pre-frontal cortex, to the hippocampus and then—the last stop—to the amygdala.

It makes perfect sense. This is why I don’t display much emotion, even when I’m excited; I have to think about it first. Anything you say to me literally has to go through like 40 billion extra neurons before I can form any sort of emotional response about it. So to the person who’s speaking to me, it looks like I don’t care or I just have no interest in their life when, in fact, what they said hasn’t even gotten to my emotional center yet.

The second main difference to note is that there are actually differences in the way the brain handles certain chemicals, specifically dopamine and acetylcholine. Extroverts are not as senstive to the neutrotransmitter dopamine so they require more of it in order to be energized to act. A lack of dopamine will cause, in extreme cases, the inability to willingly move one’s body—extreme depression, in other words. Dopamine is produced when the sympathetic nervous system is activated via adrenaline production. The sympathetic nervous system is the one that propels you to action. Extroverts feed their brain by moving their body.

Introverts, however, are more sensitive to dopamine, and don’t require as much of it. The need more acetylcholine, which is the primary neurotransmitter in the frontal lobe and allows analysis, abstraction, and long term memory formation in the brain to take place easier and faster. More Acetylcholine is generated when the parasympathetic nervous system is active: the one that shuts the body down, limits movement, and enhances relaxation. Introverts feed their brain by not moving their body.

That might be more technical than you care about, so here’s the basic deal: introverts are easily overstimulated by being around people and stuff whereas extroverts need to be around people and stuff.

And that really is the crux of the whole situation.

However, even among introverts, I’m of a specific type. So, as promised, here’s a list describing me. Some of these things I’ve already explained, and if you know me, you probably know all of them anyway, but I’ll say them again for the sake of completeness. It’s kind of a Cliff’s notes for understanding me without having to know all that stuff about amygdalas and lobes and soforth.

1. I don’t do small talk. If I’m genuinely interested in your personal situation, I will ask.
2. I have emotions. No, I won’t show them to you.
3. To save time, assume I have no personality. Also, I’m not impressed by yours.
4. If I’m staring off into space looking zonked out, I’m thinking. Don’t bother me. I see you and I’ll acknowledge you when I’m done.
5. Don’t touch me. I am easily overstimulated by input from the five senses. Contrary to popular belief, hugs are not universally beneficial.
6. Don’t share a problem with me unless you want me to help you find the solution. That’s what I do.
7. I will be blunt to you; I would like you to be the same to me. You won’t offend me.
8. If it doesn’t work, it’s only important insomuch that it prevents one from making the same mistake twice.
9. You will annoy me greatly if you pass a judgement without explaining why you believe the way you believe. Your conclusions, even if correct, are worthless without a reasonsing process behind them.
10. There are only five people in my life I consider to be friends. All others are acquaintances. However, I will, for convienience, refer to some of these as friends, as well. Note that most people who fall in the acquaintence catagory would be considered by others to be friends, so if you’re one of these people, you’re doing good. What most people would all “acquaintences” I call “people I know”.

Suffice it to say that this has all been very enlightening. I keep seeing new things in my life that reflect my personality in subtle ways that I never would have noticed before. In almost all of my old Not A Blog™ entries, there are examples of these things going on and it’s delightful to read them with this in mind.

-Ted