The Brain and its Characters
Meet the Characters
The brain is a complex organ. It controls everything humans think and feel and allows us to interact in an ever increasingly multifaceted world. But, when you get right down to it, the brain looks quite fragile and uncomplicated. So how can such a humble-looking organ cause so much distress in our everyday lives?
I think this question is best answered by one of my favorite science blog writers, Tim Urban. He explained there are two forces in our brains working together (and sometimes against each other) that control every thought, every emotion, every aspect of our functioning. According to Tim, these two characters exist to keep us safe and in control of our environment, and also allow us to feel the pleasures of a fresh-baked cookie or a warm summer breeze. These characters also allow us to feel loss, grief, and emotional pain that can often shift the entire course of our lives.
While our brains are not completely segmented into two characters, per se, the brain develops over time and two key biological systems work together to form human consciousness.
The first character to discuss is the limbic system of the brain. Evolutionarily speaking, this is an old brain system that all mammals possess. It is the part of our brain that responds immediately to danger and sits quietly in the background when we are relaxing at home. There are few things the limbic system has to worry about – mainly our immediate safety and what we are feeling in any given moment. The human limbic system is similar to that of an animal brain: when a threat appears, the limbic system jumps into action through a rush of adrenaline, intricate muscle movements, and an increase in heart rate and blood pressure. These reactions to danger keep the animal alive for another day, and the human limbic system has helped our species survive and thrive for millennia.
The next character in our brain’s development story is that of the prefrontal cortex (PFC). The PFC came along in human evolution approximately 6 million years ago and gave rise to language, emotional expression, and high-level executive functioning (Smaers, et al, 2017). The PFC helps us to rationalize situations, create imaginative scenarios in our minds, and respond appropriately to threats. Unlike the limbic system who is easily startled at every noise, the PFC can take in information from our senses to better understand the noise and whether or not our survival is at risk.
Working together, the limbic system and the PFC have shaped the human brain into the machine it is today. These two characters play vital roles in our everyday functioning and also inform our life’s biggest decisions. These characters allow us to feel the thrill of a roller coaster without truly fearing for our lives. They allow us to love another person so deeply while also making logical decisions about marriage and commitments. They allow us to feel and to think simultaneously. But what happens when these characters are no longer playing on the same team? What happens when one character has more power than the other?
The Limbic System vs. The PFC
The interplay between the limbic system and the PFC in the brain is quite refined and delicate. When these systems start to work against each other, the destruction to human function can feel like a never-ending battle.
When the PFC is in charge, things may seem reasonable on the surface. A person may appear to be logical, rational, smart, and never makes a wrong decision. With the wave of a wand, things seem to fall into place. However, bubbling below the surface, you may find a suppressed limbic system waiting to angrily take over. We often stereotype people who are run by their PFC as being cold, calculated, or having a difficult time expressing emotions. With the PFC running the show, life is done and is often successful, but may not be enjoyed to its fullest potential.
On the other hand, the limbic system can just as easily run the show. When this system is in charge, a person may feel every emotion so deeply that the ups and downs of everyday life are joyous and catastrophic at the same time. A person being driven by the limbic system may even start to appear as animal-like: skittish, easily startled, shy, and wary of their environment. However, the limbic system also allows us to develop meaningful relationships, love unconditionally, and protect ourselves from danger.
Pitting the limbic system and the PFC against each other can certainly be a recipe for disaster. And even though we may think the PFC is smarter, he often loses this battle…but why?
The PFC often loses because he is young in terms of the evolution of the human brain. The limbic system, on the other hand, has been around for tens of millions of years (Smaers, et al, 2017). The limbic system is the human brain’s default network and when threatened, jumps in to take control.
The Limbic System Runs the Show
It is no wonder why humans, when exposed to an acute stressor, react before we think. This is our limbic system taking over the PFC to keep us out of harm’s way. The fight or flight network came pre-installed in humans and the PFC is like a new software upgrade.
As hard as we may try, this default networking in the human brain is unchangeable. At birth, the limbic system is just about fully developed. A few weeks into life, the limbic system is in full work mode. Infants cry for everything they need; eating and sleeping are about as complex as life gets. Its not until much later into puberty that the PFC comes online. The PFC reaches full maturity around late teens to early twenties and even then, can spend a few more years developing. By the time the PFC makes his appearance and begins to fully contribute to human functioning, the limbic system has been around for more than a decade.
As an example, when a stressful life event occurs when we are children, the limbic system is all we have to rely on. We may have left our trusted blanket or stuffed animal at the playground and we cry and scream that it is gone forever. The limbic system thinks that this dependable, deeply loved, and necessary item is key to our survival and we will panic until it is returned to our grasp. As the PFC is not yet in the picture, we as children have no way to understand that we are responsible for the lost blanket, and logically must retrace our steps to go retrieve it.
However, even as fully developed adults with properly developed PFC’s, the limbic system can still take over and run the show.
There are many ways this can happen, and in the following series, we will talk about the ways the limbic system can take charge over our functioning, leaving the PFC far behind.