When you think your thoughts, where do they go?12 min read

Reading Time: 7 minutes

Feel your head for a moment. Yeah, it’s pretty big, and in it is one of nature’s biggest brains: The Human Brain. The brain is a wondrous thing. It allows us to understand the world around us and interact with it. So essentially, without our brains, we’d just be limp pieces of flesh.

Now, wait a minute, what was it that made me think that thought. Well, the brain, of course. But the question remains, what part of this incredible (my brain is a bit boastful today) organ allowed me to think? Let’s find out.

_{Warning: It’s about to get pretty icky}

The Brain may be the reason that we know that slugs cut off their own heads to fight off parasites, but, surprisingly enough, we know alarmingly little about our own mysterious minds. However, scientists have taken one step further into the mental black hole of our brains. They have finally learned that it is, in fact, the prefrontal cortex that fires the most neurons every time we think.

Whatt????

Alright, alright. To understand what on Earth I just said, let’s first look at the parts of the brain.

…the prefrontal cortex fires the most neurons every time we think.

The Brain can broadly be divided into the cerebrum, the cerebellum and the brain stem. While the cerebellum and brain stem deal with balance, muscles and our physical functions, the cerebrum is the part that hosts what we know as the complex and slippery mind. And, well, it is after, all the mind that generates all the absurd thoughts we think.

The cerebrum has four sections, called lobes: frontal, parietal, temporal and occipital. Each lobe controls specific functions. 

The prefrontal cortex is a part of the frontal lobe or section of the cerebrum. But, the frontal lobe itself is pretty huge, so let’s find out where in the frontal lobe this thinking part is.

Have you ever noticed the gross spaghetti-like appearance of the surface of your brain? Yup, that icky brain intestine is known as the cortex, or the bark of the brain. 

So, you guessed it, the prefrontal cortex is in the front and on top of the cerebrum. There it is, just firing away, right behind your forehead. It is responsible for your rational thoughts, your ability to feel empathy and complex emotions such as jealousy. It even helps you plan ahead for your future and make the choices such as picking your friends.

Unscramble the image below to find the prefrontal cortex:

Neurons

…the prefrontal cortex fires the most neurons every time we think.

That alien-looking thing is known as a neuron. It is a single cell that joins billions of others to make up the nerves in your nervous system. Nerves are like wires that carry communication signals or impulses around the body. The brain is full of nerves or the messengers of the body. Either these nerves carry messages from the brain to the rest of the body, or they chatter away within the skull. 

When the nerves chatter with each other, each neuron fires an electric signal to the next. It is these signals that scientists study to learn a bit about the brain.

So, how do they do it?

Usually, when scientists have to study the brain and its neurons, they study it from the outside. They take pictures of the brain using an imaging technique known as an MRI, or they perform an EEG. An EEG or electroencephalography is a brain-scanning technique where the doctor attaches several tiny metal discs to the patient’s head. As these discs are made of metal, they can receive and conduct the electrical signals that the brain’s neurons are firing. Those signals are then read by the doctor, and he/she can tell which part of the brain has more neurons “lighting up”.

ECoG

The problem with this technique is that the skull and protective membrane around the brain make the EEG readings inaccurate. That’s why, for this study, scientists performed an ECoG or electrocorticograhy. This technique is much like an EEG, but instead of placing the discs or electric conductors on the head, scientists place metal conductors directly on the patients exposed brain. This gives a more accurate reading but is a very risky process.

That is why the technique was tested on only sixteen patients, all of whom were already enrolled for brain surgery for a condition known as epilepsy.

Watch this video to find out how doctors study the brains of epilepsy patients:

…the prefrontal cortex fires the most neurons every time we think.

Once the scientists had hooked up the trial participants to the ECoG machine, they had to make them think. Scientists showed them different images and sounds, and the patients had to perform simple tasks.

Wait a minute, they were AWAKE?!!!

Yup, that’s right! Even though their skull was cracked open and their brains were on display, the patients had to keep their eyes open and stay awake.

The tasks

The scientists asked the patients to perform increasingly difficult tasks. First, they had to do something simple like moving a limb. Then, they were given more and more complex tasks, like repeating a word and thinking of its opposite word or antonym.

Watch the brain light up as a patient thinks of the antonym of the word humid:

Did you notice anything? Yup, all the thinking was right there in the front of the brain.

Here’s what happened:

.

First, a different part of the brain responded to the information it was getting.

Then, the thinking began. The prefrontal cortex(shown in red) was called to action. It worked fast, and the neurons got chatting. They quickly sent signals around within the prefrontal cortex, and the answer had been thought of.

The prefrontal cortex called upon the part of the brain that would send signals to the patient’s throat, tongue and mouth, so they could give the answer.

And that’s it, the task was done!

Scientists have compared the prefrontal cortex to the glue that holds together all brain activity. It is the responding or processing centre of the brain where any information received is sent for sorting. The frontal cortex fires its neurons and does the thinking needed. Then, the neurons in the region determine if the thought needs an action. If yes, the prefrontal cortex contacts the section of the brain that gets the body into action.

“It’s the glue of cognition.“

Neuroscientist Robert Knight 

Soooo, that’s how you know the prefrontal cortex that fires the most neurons every time we think.

With Excerpts From: WION, ScienceAlert, Hopkins medicine, and The Science Times.