The Three Brain Regions That Control Your Life In Unseemingly Ways
We Are Our Thoughts
I like to think of it this way:
Our nervous system is set on comfort, our “soul” aims at growth.
The brain is incredibly complex and often tries to deceive us with neurotransmitters and hormones of all kinds (dopamine, serotonin, oxytocin, adrenalin, endorphins, etc).
There are trillions of signals per second and millions of kilometers of neural pathways that are constantly processing and releasing information.
The lateralization of brain function is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other.
The left side of the brain is primarily responsible for analytical & rational thought, planning, verbal cues, logic and perception while the right side centers around emotional thought, impulsiveness, creativity and imagination, just to name a few.
Emotions are only present in the limbic system to help us survive and put us in a state of well-being. They basically want to communicate two things: attraction and repulsion in all kinds of ways.
We want joy, contact, knowledge and hate fear, complexity, and unkindness.
The basic cell type of the nervous system, what we call the “brain cell”, is the neuron. The hundred billion or so neurons in our brain communicate with each other and form complex circuits.
In addition, there are glial cells that do a lot of work — providing structural support and insulation for neurons, storing energy for them, and helping to repair neuronal damage. Of course, this comparison between neurons and glial cells is completely wrong.
There are about ten glial cells for every neuron, and they come in different subtypes. They have a great influence on how neurons talk to each other and also form glial networks that communicate quite differently from neurons.
Overall it is not a matter of new cells growing, because the number of brain cells is the same in children and adults. It depends on how these cells are connected. At birth, a baby’s neurons are disconnected and unconnected.
In the first two years of life, they start to connect extremely fast when they receive sensory information. Every second, up to two million new synapses, are formed in the brain of an infant. By the age of two, a child has over one hundred billion synapses, twice as many as an adult.
It has now reached a peak and has far more connections than it needs.
As you mature, 50% of your synapses are broken down.
For the rest of this article, I will be quoting much from “Behave: The Biology of Humans at Our Best and Worst” by Robert Sapolsky. He takes you through a vivid journey, from explaining interesting and crucially important parts of the brain to the triggers and pathways that activate these parts. I can highly recommend it, so my deepest respect and appreciation go to Robert Sapolsky.
The Amygdala
This part of the brain has a dual role with aggression as well as with facets of fear and anxiety. Fear and aggression are necessarily intertwined — not all fear causes aggression, and not all aggression has its roots in fear.
Fear usually increases aggression only in those who are already prone to it; in those subordinates who have no way to safely express their aggression, fear does the opposite.
The dissociation between fear and aggression is evident in violent psychopaths, who are the opposite of fearful — both physiologically and subjectively they are less responsive to pain; their amygdalae are relatively less responsive to typical fear-inducing stimuli and are smaller than normal.
This fits the picture of psychopathic violence; it is not exercised in excited response to provocation. Instead, it is purely instrumental, using others as a means to an end with emotionless, ruthless, reptilian indifference.
So fear and violence are not always closely linked. But a connection is likely when the aggression elicited is reactive, frenzied, and splattered with spittle.
In a world where no amygdaloid neuron needs to be afraid and can instead sit under its vine and fig tree, the world is very likely a more peaceful place.
I’ve already talked about the impact stress has on our daily lives in another article and the differences between prolonged and immediate stress.
The amygdala becomes overactive and more strongly coupled to the pathways of habitual behavior; it is easier to learn fear and harder to unlearn it.
We process emotional information more quickly and automatically, but with less accuracy.
Frontal functions — working memory, impulse control, decision making, risk assessment, and task shifting — are impaired, and the frontal cortex has less control over the amygdala, so we become less empathic and prosocial.
The Prefrontal Cortex
The PFC is considered to be the seat of executive functions (which control one’s behavior taking into account the conditions of the environment) and working memory. It also plays a crucial role in the evaluation of the pain stimulus.
During REM sleep, when dreaming occurs, the frontal cortex shuts down and the dream writers can go wild. When the frontal cortex is stimulated during dreaming, dreams become less dreamlike and one is more self-aware.
There was an evolutionary selection for delayed maturation of the frontal cortex. If the frontal cortex matured as quickly as the rest of the brain, there would be no pubertal turbulence, no nervous, itchy exploration, and no creativity, none of the many pimply-faced adolescent geniuses who dropped out of school and invented concepts in their garages.
And for every individual who succeeded at procreation thanks to pubescent ingenuity, there were far more who broke their necks through pubescent imprudence instead.
Robert does not believe that the delayed maturation of the frontal cortex evolved to allow adolescents to go overboard. He thinks it is delayed so that the brain makes the right decisions. We learn, change, and adapt. Nowhere is this more important than in the frontal cortex.
An oft-repeated fact about adolescents is that “emotional intelligence” and “social intelligence” predict success and happiness in adulthood better than IQ or SAT scores, which is the case. It’s about social memory, emotional perspective-taking, impulse control, empathy, the ability to work with others, and self-regulation.
During the transition from childhood to adolescence, the brain shows an increasing response to rewards in areas related to pleasure-seeking (one such area is the nucleus accumbens).
In teenagers, activity here is just as high as in adults. An important point, however, is that activity in the orbitofrontal cortex, which is involved in decision making, attention, and simulation of future consequences, is still about the same in teens as in children. A mature pleasure-seeking system combined with an immature orbitofrontal cortex means that teenagers are not only emotionally oversensitive but also less able to control their emotions than adults. On the other hand, they find it extremely easy to empathize with other people and their emotional world.
Areas involved in social reasoning (such as the mPFC) are more strongly connected to other brain regions that translate motivations into actions (the striatum and its network of connections).
This could explain why teens are more likely to take risks when their friends are around.
A final area of frontal damage. Adrian Raine of the University of Pennsylvania and Kent Kiehl of the University of New Mexico report that criminal psychopaths have decreased activity in the frontal cortex and decreased coupling of the PFC with other brain regions (compared to non-psychopathic criminals and non-criminal controls).
In addition, a shockingly high percentage of individuals incarcerated for violent crimes have a history of concussive trauma to the frontal cortex.
The Mesolimbic and Mesocortical Dopamine System
Eating triggers dopamine release in hungry individuals of all species, with humans having an additional twin. If you show someone a picture of a milkshake after they have had one, dopaminergic activation rarely occurs, but satiety does. But in subjects who have been dieting, there is further activation. They work to limit their food intake, and a milkshake simply makes them want another one.
The mesolimbic dopamine system also responds to aesthetics. In one study, subjects listened to new music; the more signals shooting in the accumbens, the more likely they were to buy the music afterward.
Patterns of dopamine release are most interesting when it comes to social interactions. Some results are downright heartwarming. In one study, a subject played an economic game with someone in which one player is rewarded under two circumstances: (a) if both players cooperate, each receives a moderate reward, and (b) if they stab the other person in the back, the subject receives a large reward while the other person receives nothing.
While both outcomes increased dopaminergic activity, the increase was greater with cooperation.
The anticipation of an event and being “anxious” for it is the time when the most dopamine is released, not when that event actually occurs.
In an experiment with rats a light turns on, they pull a lever, and the reward is received. The scientists deliberately changed the chances of the reward being granted from 100% to only 50% of the cases. Remarkably, dopamine is released much more once the new scenario has been learned. And why?
Because nothing boosts dopamine release like the “maybe” of intermittent reinforcement.
This extra dopamine is released at a specific time. In the 50 percent scenario, the lights come on and produce the usual anticipatory dopamine surge before the lever-pressing begins.
In the anticipatory days, when pressing the lever always brought a reward, the post-press dopamine level remained low until the reward arrived, followed by a small dopamine surge. In this 50 percent scenario, however, dopamine levels rise as soon as pressing is completed, driven by the uncertainty of “maybe yes, maybe no.” Going from 50 to 25 percent and from 50 percent to 75 percent reduces the amount of uncertainty. And the secondary increase in dopamine levels at a 25- or 75-percent probability of reward is smaller.
Although the dopamine system is similar in numerous species, humans do something completely different: they delay rewards for an insanely long time.
No warthog restricts its caloric intake to look good in a swimsuit next summer. No gerbil works hard in school to get good SAT scores, to get accepted to a good college, to get accepted to a good graduate school, to get a good job, and to get accepted into a good nursing home.
We do something even beyond this unprecedented gratification delay: we use the dopaminergic power of the happiness of striving to motivate us to work for rewards that come only after we die.
Depending on the culture, this may be the knowledge that your nation is more likely to win a war because you sacrificed yourself in battle, that your children will inherit money because of your financial sacrifices, or that you will spend eternity in paradise.
Another experiment in which questions were answered and brain activity was scanned. In children, a correct answer led to an approximately equal increase in activity regardless of the amount of reward.
In adults, small, medium and large rewards led to small, medium and large increases in accumbens activity.
And in adolescents? After a medium reward, it looked the same as in children and adults. A large reward led to a huge increase, much larger than in adults. And the small reward? Accumbens activity decreased.
As they mature, adolescents also increasingly distinguish between harming people and harming objects (with the former seen as worse).
Harming people increasingly activates the amygdala, whereas the opposite is true for harming objects.
Interestingly, as adolescents age, there is less distinction between the recommended punishment for intentional and unintentional harm to objects. Either way that damn thing has to be repaired nonetheless.
I hope you enjoyed reading this little article and once again I’m referring to the amazing works of Robert Sapolsky. Go check out his new book “Behave: The Biology of Humans at Our Best and Worst”.
—
Subscribe to my newsletter to receive similar content directly to your inbox.
I sincerely hope my posts impacted your life in positive ways!
https://robinklose.medium.com/subscribe
Since I don’t get paid by Medium directly, it would mean the world to me if you could check out https://ko-fi.com/robink1 and maybe even buy me a coffee with a small tip!
Every amount is greatly appreciated, especially if you leave a kind note at the end :)
