For centuries, our practice of medicine and understanding of disease was limited by one simple factor: we couldn’t look inside the human body. When pioneers began peering inside the human body, that always happened after a person was deceased – and that practice itself was considered heresy by the dominant powers of the time.

Fast forward several hundred years, and our available technology is nothing short of magic, compared to where we started. When the stigma against studying cadavers faded, we learned everything we could from them, which is a considerable amount.

However, we still had a problem: we couldn’t look inside a body while it was alive and functioning.

Then we arrived in the 20^th century, and experienced a technological revolution that had a significant impact on medicine and medical technology.

We can now look under the hood, as it were.

X-ray technology allows us to see directly into the body but limits our view to bones and cartilage. Microbiology gave us specific testing that allows us to look indirectly into the body, by revealing the microscopic interplay of the various chemicals and molecules related to typical function, disease, and pathology. Magnetic resonance imaging (MRI) and computed tomography (CT) scans allow us to see inside the body, including the soft tissue that x-ray technology cannot see – and including the ability to see brain tissue and detect brain tumors and other structural anomalies.

There was still a problem, though: we couldn’t look inside a body in action.

But the 21^st century is upon us, and the introduction and perfection of a technology called functional magnetic resonance imaging (fMRI) allows us to do something that impaired our progress, particularly in the mental health field: we can now look inside a human brain while it’s working.

A New Understanding of Early Trauma

In a study published in August 2020 called “Triple Network Functional Connectivity During Acute Stress in Adolescents and the Influence of Polyvictimization” a group of researchers used fMRI to examine the function of key areas of the adolescent brain while under stress.

The primary goal of the study was to learn how early trauma impacts brain structure and function, with a focus on consequences for adolescents diagnosed with anxiety disorders who experienced more than one early trauma. That’s what polyvictimization means in the context of mental health: the experience of one or more trauma that causes subsequent emotional, psychological, or relational impairment.

The theoretical basis of the study is the concept of The Triple Network Model of posttraumatic stress disorder (PTSD) and other anxiety disorders. Broadly speaking, the triple network model suggests the following:

“Exposure to both chronic and acute stressors can disrupt functional connectivity (FC) of the default mode network (DMN), salience network (SN), and central executive network (CEN), increasing risk for negative health outcomes.”

Here’s a brief explanation of the function of those three brain networks:

Perception:

The salience network integrates input from brain areas responsible for external sensory and emotional input.

Emotional Regulation:

The default mode network is responsible for introspection, retrospection, and prospection, i.e. how we integrate our emotions into our thoughts about the present, past, and future.

Social Functioning:

The central executive network integrates and directs attentional control and goal-directed behavior.

The triple network model theorizes that early traumatic stress exposure is associated with:

1. Increased activity and connectivity in the salience network, which can cause:
   • Hyperarousal and heightened threat detection
   • Impaired ability to distinguish between relevant and irrelevant stimuli
2. Reduced activity in the default mode network and decreased connectivity in the central executive network, which can cause:
   • Intrusive symptoms
   • Excessive fear
   • Impaired perception of self
3. Reduced activity and connectivity in the central executive network, which can cause:
   • General cognitive deficits
   • Impaired decision-making

In a nutshell, disruption in the function of these three networks impairs the way an adolescent sees and feels the world, degrades the ability of an adolescent to integrate feelings about the past, present, and future, and limits the capability of an adolescent to focus their attention and formulate rational plans to accomplish clearly defined objectives. Wellness treatments and products have sprung up by the dozen in recent years whether it is experiential therapies like time outdoors & in sunlight or using teas, tinctures, balms, and more. Even supplementing diet and exercise in teens with little things like vitamin D gummies, lemon balm, passionflower, or using aroma therapy with diffusers and essential oils can help with day to day progress. 

Past Trauma and Real-Time Stress Response

To conduct the study, researchers recruited 79 participants between the ages of 9 and 16 years with and without previously diagnosed stress and anxiety-related mental health disorders. Of the participants, 51 percent had no history of mental illness. These participants formed the control group. The experimental group consisted of 49 percent of study participants, and met diagnostic criteria for one or more of the following mental health disorders:

• Attention-deficit/hyperactivity disorder
• Generalized anxiety disorder
• Social anxiety disorder
• Panic disorder
• Obsessive-compulsive disorder
• Adjustment disorder

In order to quantify the traumatic experiences of the participants, researchers used the Juvenile Victimization Questionnaire. This widely accepted, evidence-based psychiatric assessment tool measures traumatic exposure among children and adolescents, using five categories:

Conventional crime:

• Robbery, theft, vandalism, assault with or without a weapon, attempted assault, kidnapping

Child maltreatment:

• Caregiver abuse, emotional abuse, neglect, family abduction/custodial interference

Sexual victimization:

• Sexual assault by known adult, nonspecific sexual assault, sexual assault by peer, attempted or completed rape, flashing/exposure, verbal sexual harassment, statutory rape

Peer or sibling victimization:

• Gang or group assault, peer or sibling assault, nonsexual genital assault, physical or emotional bullying, dating violence

Indirect/witnessing victimization:

• Witnessing domestic violence, witnessing parent assault sibling, witnessing assault with or without a weapon, burglary of home, murder of family member or friend, witnessing murder, exposure to gun violence, terrorism, riots

Experiencing one or more example of trauma in each group or subgroup indicates the presence of polyvictimization.

The next step in the experimental process – after recruiting appropriate participants – was to determine whether the presence or absence of early trauma or traumatic polyvictimization affected connectivity in the critical, trauma-related triple network of brain function and connectivity. That means they needed to put the participants under some form of stress while inside the fMRI unit, which they accomplished by using the Montreal Imaging Stress Task (MIST).

Here’s how this test worked:

• Researchers placed participants in the fMRI machine with a tablet used to complete cognitive tasks, such as math problems.
• Participants completed three 6-minute runs of each task
• Each run included alternating rest, control, and experimental conditions
  • Rest condition
    • Participants focused on a screen displaying a static task dial image
  • Control condition:
    • Researchers told participants they would not record their results as they completed math problems and submitted their answers via touchscreen
  • Experimental/stress condition:
    • Researchers encouraged participants to complete math problems quickly, within the permitted response time window
    • Researchers gave negative feedback on their performance
    • Participants received instructions to try harder
    • Researchers told participants that trying hard to get good scores was important

During the task, the fMRI unit measured activity in the target areas of the brain. The researchers collected the data from the fMRI, then applied various methods of advanced statistical analysis to arrive at a set of useful results.

Let’s look at those results now.

How Early Trauma Affects Brain Development and Function

Let’s revisit what we’re talking about here: how specific areas of the brain of an adolescents diagnosed with a mental health disorder and a history of early traumatic experiences responds to stressful situations that are neither extreme nor life-threatening.

In other words, researchers wanted to know whether early trauma affected the way this group of teens responded to acute, typical, daily stress.

Let’s also remember our definition of the triple network. It’s a combination of three brain areas related to how teens perceive the world, feel about the world, and make rational decisions about their future behavior in the world. The salience network (SN) combines and integrates sensory and emotional input. The default mode network (DMN) regulates how we feel about the past, present, and future. The central executive network (CEN) prioritizes all this input and organizes attention and action in pursuit of defined goals.

The general theory is that dysfunction in the triple network causes patterns of thought and behavior related to the disruptive symptoms associated with severe posttraumatic stress disorder. In this study, researchers sought to clarify and validate this theory. Further, they sought to determine the role of polyvictimization in triple network dysfunction.

Here’s what they found.

Trauma, Stress, and the Triple Network in Adolescents: Results

During acute stress, fMRI data showed that, compared to teens with no history of trauma, functional connectivity:

• Increased between default mode network (DMN) and central executive network (CEN) regions
  • Researchers indicate this may confirm the hypothesis that emotional hyperarousal related to the DMN can impair rational decision-making related to the CEN.
• Decreased between the salience network (SN) and the default mode network (DMN)
  • Researchers indicate this may confirm the hypothesis that decreased connectivity between these two networks impairs the ability to switch between them as needed.
  • This also indicates that irregularities in assigning a hierarchy of importance (salience) to sensory and emotional input attenuates the ability to respond appropriately to stressful stimuli
• Decreased between the salience network (SN) and central executive network (CEN)
  • This confirms previous research findings that show decreased communication and connectivity between these networks results in an increase in perceived stress levels, a phenomenon considered a primary characteristic/symptoms of PTSD.

In addition, researchers found polyvictimization was associated with:

• Reduced functional connectivity between the default mode network (DMN) and the salience network (SN).
  • This adds to previous findings of decreased DMN-SN connectivity at rest among teens with a history of trauma
  • Researchers indicate decreased DMN-SN connectivity can lead to increased stress reactivity in both the DMN and the SN, caused by repeated trauma exposure that leads to dysfunctional adaptation, including hyperreactivity or hyperarousal characteristic of PTSD and victims of complex trauma

When viewed as a whole, these results show the impact of early trauma on adolescent brain function. They describe how the effect of multiple trauma is cumulative, and compounds the negative effects of trauma. Polyvictimization exacerbates stress reactivity, emotional regulation, and cognitive function. These changes can result in an increase in disruption caused by the symptoms of anxiety-related mental health disorders.

How This Information Helps Parents and Teens

Here’s how the lead author of the study, Dr. Rachel Corr, describes the importance of these experimental results:

“While negative health outcomes have been associated separately with early life victimization exposure, disrupted adolescent neurodevelopment, and aberrant neural network responses to acute stress, no previous research had examined how these factors are related to each other. This study aimed to put together these pieces of the puzzle.”

The pieces of the puzzle they put together reveal a picture that shows early, multiple trauma has a significant, negative impact on the function the triple network. It changes the way the brain reacts to stress. Adolescents with a history of multiple traumas perceive and react to typical daily stress with maladaptive patterns that are a result of their early traumatic experiences.

Parents and teens alike can use this information to support recovery.

Teens diagnosed with an anxiety disorder and multiple early trauma now know that as a result of their early experiences, their brain behaves differently in stressful situations, when compared to teens with no anxiety and no history of trauma. This can help them get perspective on their diagnosis. It can help them understand that with time, they can restore balance to their brain and begin to change their patterns of thought and behavior.

Parents of these teens can use this information to understand that their teen’s behavior has a functional origin. Early trauma changed the way important brain areas work. This causes the atypical behavior displayed by teens with anxiety disorders. It also helps explain the severity of symptoms experienced by teens with complex PTSD who have a history or polyvicitmization.

We’ll close this article with an observation from Dr. Cameron Carter, editor of the peer-reviewed journal that published the study:

“This research shows how repeated trauma may lead to a maladaptive response to acute stress in important functional brain networks and reveals a potential mechanism by which multiple early life stressors may lead to increased neural vulnerability to stress and the associated liability to future mental health problems.”