Neurology Made Easy: Upper and Lower Brain

What is “Neurology Made Easy?”

This topic is designed to help you understand a little bit more about how our brains work! The brain is an organ, just like any other. If we give our brains the things they need, barring rare cases of a chronic biological problem, or other disability, they will work the way they are supposed to. Understanding our brains, at least on a basic level, is crucial to helping them work well. It is hard to have a healthy and happy life if our brains aren’t doing what they’re supposed to!

The Vagus Nerve

The vagus nerve is the way that most of the communication between our bodies and our brains occurs. It goes all along the spinal cord, with offshoots to all the major organs. Neural impulses are sent from the organs to the brain and vice versa.

The Upper and Lower Brain

The Upper Brain

The upper brain mainly refers to the frontal lobes. The frontal lobes are responsible for our higher-level cognitive functioning, such as decision-making, critical thinking, abstract thought, judgement, and impulse control. 

The Lower Brain

The lower brain mainly refers to the amygdala. The amygdala is the part of the brain responsible for protecting us from immediate physical danger. As such, it only has three tools it uses to “keep us safe:” fight, flight, and freeze. It is the primal, instinctive part of the brain.

When there’s a threat, real or perceived, you’ll notice certain physical symptoms. It might be a tightness in the chest, a pit in the stomach, a lump in the throat, or your skin might flush. That is the body sending a threat message to the brain via the vagus nerve. The message goes to the thalamus, which is like the operator of the brain. 

The thalamus then does two things: it routes the threat message to both the amygdala and the frontal lobes. The amygdala is right next to the thalamus, so the message gets there before it gets to the frontal lobes. Then, the amygdala sends a message up, intersecting that message that was coming from the thalamus to the frontal lobes. When the amygdala grabs control of the brain, the frontal lobes are taken offline. Blood is literally taken away from the prefrontal cortex and those executive functions and judgment are no longer available to us. The message goes from the amygdala back out to the body. It actually goes to the hypothalamus, which controls the adrenals at the top of the kidneys, and the system gets flooded with adrenaline and cortisol. Over 1,400 psychological processes have been identified to happen when we get into fight, flight, or freeze. Some of those things are flushed skin, sweating, the arteries constrict and heart rate increases, blood pressure goes up, which makes oxygenated blood flow more quickly so that the large skeletal muscles can be flooded with oxygenated blood so we can run or fight. The body prepares to deal with the threat.

THIS IS A PROBLEM in any situation that is not literally a physical threat, survival situation. Our body often sends up a threat message for social or emotional threats, like being vulnerable or embarrassed or when we’re in an argument. The key thing to consider is “what part of my brain do I want to be the part that is going to cope with this situation?”

In a relational setting, we NEVER want our amygdala running the show. When the amygdala is in control, we literally lose the ability to use our frontal lobes and all the important tools they include, like impulse control, rational thought, and decision making. 

What to do if the Amygdala Takes Over in a Relational Setting

You will notice that your amygdala has taken over if you notice the body cues above. If that happens in a relational setting, like an argument:

• Remove yourself from whatever triggered the response.
• Focus on something else! Leave and go do something, read, exercise, etc. (GET YOUR BRAIN OFF OF WHATEVER HAS TRIGGERED YOU).
• Give your body 20 minutes to calm down and get your frontal lobes back online.

In My Life

It can be extremely difficult to consistently apply these skills when you slide into your lower brain. Like any other skill, it takes lots of practice to get good at it. You shouldn’t be good at it automatically! I try really hard to recognize when I start slipping into my lower brain and when I don’t have the resources to healthily deal with a situation. When I am able to recognize it early enough, it is much easier to step away and get my frontal lobes turned back on. One of the most difficult things for me is when, for one reason or another, I feel like I really should stay and try and work through the situation. The problem with that is that the amygdala literally CANNOT do anything other than fight, flee or freeze, those are the only tools it has in the toolbox. It never goes well when I expect my amygdala to do my upper brain’s job!

To Learn More

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