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Thoughts, Emotions, and Memories

It was an early, chilly weekday morning, and my siblings and I had just eaten breakfast and were ready for school. I was 10 years old. My nine-year-old sister sat down in front of the burning wood stove and placed the kerosene container on top of it. My seven-year-old brother sat down next to her. They were both bored, so they started to shoot arrows at the kerosene can. Needless to say, we did not make it to school that day.

Suddenly, there was a powerful burst of fire that engulfed the stove and everything around it. The flames were beating up against the top of the ceiling. I remember it like yesterday. I went running through the house shouting: “The house is on fire! The house is on fire!” Fortunately my father was there and was able to put the fire out. Although the fire was out, I continued to run around the house shouting that the house was on fire. My father had to catch me and sit me down to stop my running and shouting. I’m sure I was near exhaustion.

Although this event happened decades ago, I can retrieve the memory just like it was yesterday. I can actually see the fire, feel myself running from room to room, and recall shouting at the top of my voice. I can chuckle now, but then I was terrified.

How does that happen? How are memories made and retained, and where are they stored? What about our emotions; where do they come from? How do I pull up a thought that happened so long ago? This will be our focus in this chapter as we continue to explore the wondrous and magnificent human brain.

Have you ever been walking along, going about your business, and a memory from the distant past just popped into your head out of the blue? Something that happened years ago! In amazement you wonder: where did that come from? In order to appreciate the functioning of the brain and get a better understanding of our memories, emotions, and thoughts, we need to take a deeper look into the anatomy of the brain. As we know, the brain is composed of approximately 100 billion nerve cells or neurons—the building blocks for the structure of the brain. Each nerve cell connects to another nerve cell through gaps, which are little junctions called synapses. The brain has 100 trillion synapses (Norden, 2007b).

Remember the game hot potato? This was a game we played when I was a child, in which we children formed a circle (a network) and passed a small object around as fast as we could. This was our way of communicating through touch. Just as we kids became a network, the nerve cells form networks that pass electrical signals from one cell to another. The brain gets its message out through the movement of nerve cells and synaptic junctions. Of course this is an over-simplification, but it demonstrates how nerve cells communicate.

So what does a nerve cell look like, and how does the transmission of signals play out in real-time?

Nerve Cells

There are many different types of nerve cells and they come in different shapes and sizes; however, they all have the same structure. Each neuron or nerve cell consists of a dendrite, cell body, axon, and presynaptic terminal. Unless you are a scientist, you probably don’t have access to a microscope. But you can get a feel for what a nerve cell looks like by looking at an old oak tree. Yes, nerve cells have a striking resemblance to trees. In fact the word dendrite literally means “tree,” and no doubt this is what scientists saw when they examined the nerve cells under the microscope.

Let’s say you are now looking at a big old oak tree. The dendrite would be the part that looks like the branches of the tree; its job is to receive signals from other neurons and pass them on to the cell body. The cell body is the powerhouse; it contains the DNA, proteins, and other chemicals. It’s where electrical impulses are initiated. In our analogy the cell body would be the junction where the branches—dendrites—converge into the tree. Then there’s the axon—the trunk of the tree. It receives electrical impulses from the cell body and carries them down into the roots of the tree—the axon terminal.

But it doesn’t stop here. In order for the nerve cell to carry important information about perception, thinking, learning, laying down and storing new memories, it has to get its message over to the next neuron. The electrical impulse from the axon must link up with chemicals in the axon terminal to get the message across the synapse and over to its neighboring nerve cell. This information occurs through chemical messengers.

Located in the axon terminal are small bags of chemicals, called neurotransmitters. Each bag contains 5,000 molecules of neurotransmitters that are released in response to strong electrical impulses from the cell body. As the impulse travels from the cell body down the axon to the end of the axon terminal, it causes an influx of calcium from outside of the cell to rush into the axon terminal, and this triggers the release of the chemicals. The chemicals are released out into the synaptic gaps where they float across to the appropriate receptors and then change back into electrical impulses for the next dendrite (Kandel, 2006).

A new area of discovery for nerve cell transmission through electrical impulses is the human heart. We have long known that the heart conducts electrical impulses during the contraction of the heart. However, new research documents that the heart, dubbed “the little brain,” contains 40,000 nerve cells and, like the brain, releases neurotransmitters and is also capable of storing memories. (Essene, n.d.)

Memory

So what do nerve cells have to do with my vivid memories of a childhood fire? Everything. This is where the initial communication takes place. It is here on the nerve cells that information is registered, encoded, and locked into permanent memory. This is not as simple as it sounds.

Psychiatrist and neuroscientist Dr. Eric Kandel won a Nobel Prize for his research in memory storage and formation. He demonstrated the molecular basis of memory and showed that long-term memory is a result of several factors: neurotransmitters, protein kinases, ion channels, and transcription factors called CREB, in which their proteins bind with DNA. These series of events cause certain genes within the nucleus of the cell to switch on and others to switch off. These chains of events initiate the growth of new synaptic connections and cause stabilization of memory formation (Kandel, 2006). Wow that’s a mouthful!

My memories of the fire during my childhood were encoded in what is called flashbulb memory. Flashbulb memories leave vivid pictures in the mind, just like a photo, a snapshot of who, what, when, and where. These memories are laid down during emotionally charged events. For instance, I remember exactly where I was on September 11, 2001, and can see the room in which I was standing and the vivid pictures on TV as the Twin Towers were coming down. Many older Americans can recall where they were when they heard about the assassinations of John F. Kennedy and Martin Luther King, Jr. These are flashbulb memories. But most long-term memories are not stored as highly charged, emotional events. In general, long-term memories require repeated exposure, spaced training with intervals of rest (Kandel, 2006). It is true, practice makes perfect when it comes to making memories.

There are many types of memories, but they fall into two stages. In his book In Search of Memory: The Emergence of a New Science of Mind, Kandel indicates the two stages of memory: short term, lasting from minutes to hours, and long term, lasting days to weeks to years. These memories have two forms: explicit and implicit, and they are stored in different areas of the brain. Kandel states:

In the short term, explicit memory for people, objects, places, facts, and events is stored in the prefrontal cortex. These memories are converted to long-term memories in the hippocampus and then stored in the parts of the cortex that correspond to the senses involved—that is, in the same areas that originally processed the information. Implicit memories of skills, habits and conditioning are stored in the cerebellum, striatum and amygdala. (Kandel, 2006)

Memories are stored all over the brain. My visual picture of the fire is stored in the occipital lobe of my brain, the site of vision. My words, “The house is on fire!” are stored in the area of hearing—the temporal lobe. The smell of the fire is recorded in the olfactory tract (the smell detectors of the nose), and then stored as an emotional memory in my limbic system. All this information is stored in memory on different nerve cell pathways, but it comes together to give me a complete recall.

Memories from that fire years ago are no doubt encoded in both my explicit and implicit memory: the people, place, and event. Not only do I recall what happened but also the emotions that accompanied the event. What good is a memory without an emotion? The event would be bland, especially if it was a positive emotion. Just think about it, what if you looked back at your wedding day and just remembered the event without the positive feelings of excitement and jubilation? What good is the memory?

Emotions give life and color to our experiences. But where do they come from? What caused the fear and terror I experienced during the fire? In order to answer these questions, we need to go a little deeper into another structure of the brain, the limbic system—the site of emotions.

Limbic System

The limbic system is the site from which positive and negative emotions emanate; it is also the site of learning and memory. It consists of several structures. The major ones include the hippocampus, thalamus, hypothalamus, septum, and amygdala.

 The hippocampus is located in the temporal lobe of the brain and is involved with learning and memory.

 The thalamus is located on top of the brainstem and acts like a relay station that receives, processes, and sends information to various parts of the brain, especially the higher levels of brain activity.

 The hypothalamus is located under the thalamus; it has many functions, but for limbic purposes it involves the regulation of hormones and the autonomic nervous system.

 The septum, located in the midline of the brain, is involved in mood, pleasure, sexual gratification, and rage.

 These structures are involved in other roles as well as limbic functions; however, it is the amygdala, another limbic structure, whose key role is emotional reactions (Sapolsky, 2007).

The amygdala is a small, almond-sized structure—one in each hemisphere of the brain—located deep within the temporal lobes. It acts like a storage site for emotional responses, especially those related to fear. It is involved in the fight and flight response. This little structure reminds me of a fire truck speeding down the road, with lights flashing and alarms blaring. This visceral response can be so loud that it’s deafening, and all other controls in the brain appear to be on mute. The amygdala is a wonderful built-in feature to have if the house is on fire, as was the case when our house caught on fire. I was sounding the alarm at the top of my voice. My emotions were appropriately excessive. I was running around the house like Speedy Gonzales, yelling, “The house is on fire! The house is on fire!” Even though the fire was out, I continued to run and sound the alarm, until my father caught me and sat me down. It was then that my frontal lobe, the site of reasoning and judgment, could look at the facts and analyze the situation, which was the fire is now out.

This built-in system is very effective in the face of any danger, such as running from an intruder or jumping to safety. In these situations it’s a true lifesaver. But the amygdala can also get us into trouble. There are many individuals who regret their impulsive emotional response to someone else’s behavior. For instance, a teacher in Houston was caught on tape beating her student unmercifully for his bad behavior. She had obviously lost touch with her frontal lobe, and her amygdala was out of control.

Our emotions are registered in the amygdala before we are conscious of the situation. Think about the last time you were incensed about something; that emotion began so quickly you were not even aware that it was happening. A positive emotion, such as a smile from a baby or loved one, generates an automatic smile in most cases, unless you are Mr. Grump. Studies indicate that an emotional feeling occurs within milliseconds, and it takes 10-15 seconds before it begins to subside (Ekman, 2003).

Psychologist Paul Ekman, author of Emotions Revealed, has traveled internationally and in the United States studying emotions for over 40 years. He states “emotions are universal across cultures” (p. 58). He indicates that there are seven basic emotions: sadness, anger, surprise, fear, disgust, contempt, and happiness. Ekman goes on to say that these emotions are experienced in anticipation of something sensed to be either right or wrong (2003).

In response to each emotion, we have a specific chemical reaction that corresponds to that feeling. For example, we have different types of tears—tears of sadness and tears of joy. We also have tears that come from irritants like onions and tears that moisten our eyes. Dr. William Frey, a biochemist at the St. Paul-Ramsey Medical Center in Minnesota, performed studies analyzing tears. He and his team looked at emotional tears from a negatively charged stressful encounter and compared them to tears from irritants. His findings revealed that emotional tears contained a higher concentration of protein-based hormones: prolactin (lactating hormone), adrenocorticotropic hormone (stress hormone), and leucine enkephalin (natural painkiller) (Skorucak, 2010). Other studies show that tears that moisten the eyes contain lysozyme, a chemical which washes away bacteria. Tears not only relieve pain and stress, but also kill little critters.

The body produces many other types of chemicals and hormones. Many of us are familiar with the runner’s high, that feeling of euphoria after exercising. This is produced by the natural chemicals called endorphins. Or perhaps you’ve sprained your ankle and are in pain; the body produces natural painkillers known as enkephalin, which are similar to the narcotic morphine—working on the nervous system to inhibit pain.

We produce many hormones and neurotransmitters which communicate how we are feeling: chemicals such as serotonin, which regulates mood; epinephrine, a form of adrenaline which involves the stress response; dopamine, which causes pleasure; glutamate, which excites nerve cells to fire; and GABA, which inhibits the nerve cells. Scientists have identified approximately 70 chemicals that the body manufactures, and they believe that there are many more waiting to be discovered (Norden, 2007d).

Thoughts

We have looked at our nerve cells and have seen that we have 100 billion trees making 100 trillion connections. These are the building blocks for the brain. It is here on these trees that electrical impulses are produced and chemicals are made which cause thoughts to become permanent, store memories, and produce emotions that can be relived.

But what about our thoughts; where do they come from? What generates that initial thought? You know the kind of thought that comes out of the blue when you are just relaxing and something just pops into your head. You may have had an ingenious thought that moved your career into a new and exciting direction. And you wonder: where did that come from? Well, where does it come from? In search of the answer to this question, I spoke with three leading neuroscientists, and the answer to this question was quick and short. “We don’t know!” Science has not been able to figure this one out. But what we do know is that information comes from the outside world through our five senses, which give us cues and activate previous memories. However, that initial thought, which just appears in the mind, we don’t know.

Trying to answer this question is like trying to discuss how God created the universe. We see the evidence, but we don’t know how He did it, except that He said, “Let there be” and of course there it was. Science cannot explain the origin of our thoughts; however, Scripture gives us a little insight. In Deuteronomy 29:29, God says: “The secret things belong unto the LORD our God.” This just sums it up. Some things we will never know this side of heaven. However, we do have hints.

Throughout Scripture we see information regarding the mind, what it does, and its capacities. For instance in Proverbs 23:7, we read: “For as a man thinketh in his heart, so is he.” The word “heart” has several connotations—the mind, emotions, and the physical heart (Strong, 1995). This text is referring to the thinking part of the brain (frontal lobe), the emotions aspect (limbic system), and the physical heart. It is our thoughts and feelings that make us who we are.

When we look back at the anatomy of the nerve cell, we see a biological process, electrical current, and chemical reactions. It has only been within the last few decades that science has been able to demonstrate what Scripture said thousands of years ago. We now have scientific proof that by beholding and thinking we become changed. When we think, information travels on our nerve cells, and then branches out to other cells. Thoughts dwelled upon leave indelible impressions that become memories and are stored in the mind. What an incredible and awesome gift!

This brings to mind another question: why do we have a brain? As a reader you might think, “That’s a silly question. We have a brain to think, talk, walk, and do what a brain does.” Yes this is true, but I believe that there is a higher calling, a higher level that transcends this. We were created in the image of God, made in His likeness; “For in Him we live, and move, and have our entire being” (Acts 17:28). When we look around, no other mammal has been given this incredible gift that God has given to man, the human brain.

It is only with the human brain that we are capable of experiencing an array of emotions, acquiring knowledge, and expressing and exchanging ideas. It is with the brain that our most precious memories have been vaulted and can be summoned at command. This is what we do in the mental realm, but we are also spiritual beings and have a higher calling which is spiritual in nature. The human brain was given so that we could connect and communicate with our Creator God. It is with the human brain that our humanity meets with Divinity, and when surrendered to Him, He writes His thoughts upon the nerve cells of our mind. What an exalted privilege.

Take the Challenge

Allow Him, the Creator God, to transcribe His thoughts, emotions, and character on the pathways of your nerve cells. “Let this mind be in you, which was also in Christ Jesus” (Philippians 2:5).