In our last article, we examined the definition of adverse childhood experiences (ACEs) and briefly touched on what ACEs do to the brain. In today’s article, we are going to explore, in depth, the changes which occur in our brains from trauma during childhood.

As most cases of complex post-traumatic stress disorder involve adverse childhood experiences and the damage done by them, I felt it was important for us to look at how ACEs affect the developing brains of children.

Einstein’s Brain

Albert Einstein is considered by many to be one of the most intelligent men to ever grace humanity. But, what was different about Einstein’s brain? Was the density of brain cells and how well wired his brain appeared to be really much different from the rest of us? Was his brain bigger?

Although many believe our intelligence depends solely on the size of our brain, this is not necessarily true. When the pathologist weighed Albert Einstein’s brain after his death, it was found to be 1,230 grams—less than the average weight of an adult human brain, which weighs typically 1,375-1,400 grams.

He had many more glial cells than the average person, and two regions of Einstein’s brain were better connected as he lacked a groove which separates these regions. The portion of the human brain sometimes referred to as wiring is called the corpus callosum, and Einstein’s brain had a colossal one. The corpus callosum is the wiring which allows signals from the left half of the brain to reach the right and vice versa, and like an electrical signal, the better and more the wiring, the faster and easier the signals can flow.

There may have been even more differences between the brain of Albert Einstein and the rest of us, but we will never know. His brain was stolen only a few hours after his death and cut up into pieces, then sent around the world. The problem was, it was not well preserved and many of the vital clues of his intelligence were lost—gone forever.

Because the developing brains of children are growing and changing at an astonishing rate, they are very susceptible to damage to the corpus callosum and other important structures. When we consider ACEs, and complex trauma’s effect on a child’s brain which is at its most neuroplastic state, means their brain does not achieve its optimal size or connectivity.

In short, humanity has robbed itself of future geniuses because we haven’t done enough to stop the tragedy of child abuse.

What Happens When We Feel Endangered and How Does That Affect the Brains of Children?

During the traumatic events which plague children in chronic abuse situations, these kids are consistently under the threat of more violence perpetrated against them. In coping with never-ending danger, a child’s body and mind need to stay alert and ready to defend them in whatever capacity they can. 

To accomplish this state of readiness, our bodies secrete particular hormones to rev up our breathing and other functions vital, to not only find the danger but to run from it. This function is often referred to as our fight/flight/or freeze response.

Typically, after the danger has passed, our bodies will begin to calm down and the hormonal levels will drop back down to baseline. In the case of a child who is in frequent danger, these hormone levels remain high. In fact, these children’s become so used to being on high alert that they begin to see danger everywhere and all the time.

Indeed, children who experience chronic stress from adverse childhood experiences, have hormonal levels never fully returning to baseline. The tragic result is that several regions of a traumatized child’s brain are adversely affected, on into adulthood.

Some of the Brain Regions Affected by Adverse Childhood Experiences

There are several permanent brain changes caused by ACEs. They include but are not limited to the corpus callosum, the prefrontal cortex, and the limbic system.

We will look at each region and see how it affects child abuse survivors when they become adults.

The Corpus Callosum. The function of the corpus callosum is to act as wiring and connect the left and right hemispheres of the brain.

This brain region, that sits between the two halves of the brain, undergoes significant changes during its development in childhood, especially between the ages of three to six years old. This is when children are learning how to pay attention, and how to plan their behavior, and also how to respond to their environment.

During the developmental age from six to thirteen years, children develop their corpus callosum so they can learn language and increase their memory abilities.

However, in traumatized children, research done using neuroimaging has found the corpus callosum is reduced in size, meaning a reduction in the connectedness between the two brain hemispheres also.

A brain which experiences a reduction in its connectivity with the other portions of itself will have many problems coordinating learning, self-control and many other vital functions.

The Prefrontal Cortex. This area of the brain is located in the front and is vital for memory and attention plus emotional regulation and behavior regulation. Interestingly, it is also necessary for inhibition, reasoning and abstract thinking.

The prefrontal cortex is also the last part of the brain to fully mature.

However, perhaps the function most affected by exposure to ACEs is the formation of personality. This website bridges two understandings and lists these other functions of the prefrontal cortex:

  • Organizing thoughts and problem-solving
  • Foreseeing and weighing possible consequences of behavior
  • Considering the future and making predictions
  • Forming strategies and planning
  • Ability to balance short-term rewards with long-term goals
  • Shifting/adjusting behavior when situations change
  • Impulse control and delaying gratification
  • Modulation of intense emotions
  • Inhibiting inappropriate behavior and initiating appropriate behavior
  • Simultaneously considering multiple streams of information when faced with complex and challenging information

When a child is continuously under threat of danger, as with ACEs, and their body is flooded with stress hormones, this portion of the brain, when fully developed, will be smaller than it should be.

The implications are obvious. If this part of a child’s brain is injured, then when they become adults they may be incapable of doing many of the above functions adequately. Instead, these children, now adults, have severe personality and other problems directly related to their adverse childhood experiences.

The Limbic System. This portion of the human brain is considered the most primitive and is usually the first to develop in a forming fetus. Although there are many structures found here, the two we need to address are the amygdala and the hippocampus which are located very close together in our brain.

One vital truth to remember—the limbic system overrides the thinking portion of our brains. So, we will react to stimuli before we have a chance to think about it. These automatic reactions by our limbic system have proven to be an important evolutionary adaptation which has served humanity well for thousands of years. However, when this system breaks down because of adverse childhood experiences, many maladaptive behaviors can result.

First, let’s tackle the amygdala.

The amygdala is responsible for the response and memory of fear. If we encounter something which frightens us, the amygdala is responsible for our flight/flee/freeze response. It is also the part of our brain which remembers what frightened us so we can be on the lookout for that same scenario later.

Another function of the amygdala is the regulation of emotions.

The amygdala is perhaps the first part of the brain to perceive danger and react to it. So, if danger is perceived, (whether it is real or not), our amygdala immediately responds by sending out the signal to the other parts of our brain to get ready to run (or freeze or attack).

Damage done by the constant stimulation of child abuse means the amygdala cannot develop correctly. So, when ACEs are involved, the amygdala is found on fMRI (functional magnetic resonance imaging) to be abnormally small in these children, who have become adults.

In a study done in 2006, researchers used fMRI to study people living with dissociative identity disorder (DID). DID is known to be caused by severe adverse childhood experiences. In this study, the volume of the amygdalae of those studied was found to be smaller than average by 31.6%. That is an enormous difference. And similar findings are found in those who experienced ACEs and have developed complex post-traumatic stress disorder (c-PTSD/ CPTSD).

Since the amygdala is vital to our reactions to danger and remembering not only the event but the emotions which accompany them, if a person has a smaller than average amygdala they are incapable of reacting appropriately to stimuli.

Bottom line, when a person who has a malformed amygdala encounters what they perceive as a danger, whether they indeed are in danger, or not, they react. These reactions come in the form of anxiety, heightened fear responses, and flashbacks, to name only a few.

Now let’s explore the hippocampus. This region of the human brain is critical for the formation, organization and storage of new memories plus connecting triggers and emotions to these memories.

The 2006 study mentioned above, conducted on humans living with dissociative identity disorder, also found their subjects had hippocampal volumes 19.2% below normal.

The implications of these findings are profound. If an adult has a smaller hippocampus than average, not only will they have trouble consolidating memory, they will also have problems with triggers.

Triggers are an important aspect of our brain’s ability to remember how to respond when we encounter a new situation which is related to another situation we have experienced in the past. Everyone experiences triggering events, but people with ACEs have an exaggerated response to them.

For instance, you experienced a traumatic event as a child and while it was happening you could smell cologne and beer. Your hippocampus will store away those scents with the memory of that event so when you encounter those scents as an adult, you are triggered into an emotional reaction even though the danger has long passed.

The Mental Health Consequences to Negative Brain Changes in Childhood

In a future article we will examine the adverse emotional effects ACEs have on our mental health, but here I would like to outline for you just a few of them.

Here is only a partial list of some of the mental health issues which occur as a direct result of adverse childhood experiences:

  • Anxiety disorders
  • Depression
  • Feelings of worthlessness and hopelessness
  • Memory difficulties
  • Troubles regulating emotion
  • Problems concentrating
  • A change in routine thinking processes
  • Changes in behaviors

People who experienced child abuse may also experience reactionary coping skills and behaviors which are caused by the limbic system going into overdrive. These coping skills may include:

  • Yelling
  • Crying
  • Physically attacking a perceived danger
  • Shutting down emotionally
  • Hyperawareness (hypervigilance)
  • Consistent feelings of dread
  • Manipulating an environment in order to find perceived safety
  • Feeling the need to control everything in life

As we can see, the effects of having experienced ACEs can create a living hell for not only the person when they are young, but also when they become an adult.

I know this information feels highly negative, and therefore may seem a lost cause if you have experienced ACEs and are now living with complex post-traumatic stress disorder.

However, there is hope. The human brain is mailable. Scientists call this Neuroplasticity. So, while the original damage to our brain is very real, neuroplasticity says our brain can heal. In future articles, I will delve deeper into the implications of neuroplasticity, what types of trauma-informed modalities can help facilitate this, what coping skills you can use, and how our brain can learn to respond better

In the meantime, there are many ways to mitigate the effect of ACEs on our adult lives.

I have experienced all of the above effects in my life after suffering through many years of severe childhood abuse. However, I now live a fairly quiet life. Yes, I still have times when I feel triggered by stimuli which may throw me into a flashback, but I have learned how to cope with them.

If you need to speak to someone about your experiences as related to any of the articles you find here on the CPTSD Foundation blog, please join one of our free Facebook safe support groups or our low-cost Daily Recovery Support Calls. You can find the right group for you at  or learn more about the daily calls at

As always, I wish to close this article with words of hope.

Life can be difficult, and it is made even more so when we must deal with the effects of what happened to us as children. However, never lose sight of the fact that life is also a beautiful adventure.

Yes, there will always be trials and troubles, but don’t forget to take notice of the loveliness which exists all around you. Even on a cold winter’s day when the snow is flying, we can choose to sit back and consider how beautiful the flakes are and how wonderful winter is for making us appreciative of spring.

In the next article, we will explore mental health disorders which are directly traced to ACEs and the development of complex post-traumatic stress disorder.