In our previous post, we defined trauma as follows:

  • An event, or series of events, that overwhelms the central nervous system. 
  • Trauma occurs when one’s ability to defend, protect, or say no is overwhelmed. 
  • Trauma is what occurs when your solution (active response to threat) does not work. 

This definition requires an understanding of the central nervous system, so this post will explore the basics of the nervous system and the fight-or-flight response as it relates to mindfulness and trauma.

Functions of the Autonomic Nervous System

Functions of the Autonomic Nervous System

The autonomic nervous system

Our threat-response system is mediated by a branch of the nervous system known as the autonomic nervous system
(ANS). The ANS is responsible for all of our basic automatic functions like digestion, heart rate, breathing, hormone regulation, and our body’s response to stress. The ANS can be further divided into the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The SNS is commonly known as the “fight-or-flight” response and the PNS is referred to as our “rest and digest” system

 

the fight-flight-or-freeze response

It is illustrative here to think of the most primitive of all survival situations: predator and prey. A zebra at rest with no threat of predators, for instance, will be operating within the “rest and digest” functions of the PNS. That same zebra being chased by a lion will immediately experience drastic physiological changes with the activation of the fight-or-flight response of the SNS: heart rate increases, breathing increases, large amounts of stress hormones like cortisol and adrenaline are released into the bloodstream, pupils dilate, blood pressure increases and any non-essential functions like digestion stop. Essentially - the zebra’s nervous system prepares it to run for its life.

This fight-or-flight response is the zebra’s active response to threat (solution). As long as the zebra can continue to run or fight back, it’s SNS will remain active. As soon as the zebra is caught, however, an entirely different nervous system reaction occurs - the “freeze” part of the “fight-flight-or-freeze” response. In the case of being caught by a lion, the zebra’s nervous system has literally been overwhelmed and has no further solution to offer. This overwhelm point is what we would consider trauma - the active response to threat did not work.

Past, Present, & Future: The Role of the Pre-Frontal Cortex

The example of a zebra is useful because the ANS is common to all mammals - including humans. When a human nervous system reaches the point of overwhelm it results in a state of collapse, immobility, and helplessness known as dissociation. The biggest difference between the human brain and the zebra brain is the pre-frontal cortex - the part of our brain that handles complex functions like planning ahead, abstract thought, empathy, and most of our other distinctly ‘human’ qualities. The pre-frontal cortex clearly has its advantages for us as a species, though when it comes to threat response we are at a distinct disadvantage: we are the only species capable of vividly re-imagining, and thus re-experiencing, stressful and traumatic events. 

In other words, zebras (and other mammals) do not experience post-traumatic stress disorder because their nervous system is responding only to cues in the present moment - not re-imagined horrors from their past. A zebra that survives a traumatic encounter will quite literally “shake it off” and return to a resting nervous system state once they are safe from harm. A human who has been through something traumatic, on the other hand, dissociates from the physical release of trauma and instead tends to mentally replay the scenario. This mental replay can actually activate the SNS in exactly the same way that a real threat would - as far as the nervous system is concerned there is no difference between real and perceived threats. Thus, unresolved trauma tends to live in the nervous system, cycling a person through states of high SNS activation and dissociation and resulting in a chronic stress state characterized by high levels of cortisol and adrenal fatigue - the biological underpinnings of PTSD symptoms like anxiety, fear, flashbacks, depression, insomnia, hyper-vigilance, and emotional detachment.

We are often by perplexed explosive outbursts, emotional volatility, and reactions that seem out of proportion to the actual event. It is important to remember, however, that someone who has experienced a trauma is not necessarily responding to events in the present moment. Instead, their stress response system lives in a state of hyperarousal as a result of past experiences and is easily triggered into a fight-or-flight response. When the fight-or-flight response is active the most helpful action we can take is to provide resources and solutions (coping skills, choices, deep breaths, space to calm down) until the nervous system re-enters a resting state.

Nuances of Trauma

In summary, our expanded definition of trauma now includes a number of important nuances:

  • Trauma occurs when one’s solution (active response to threat) does not work (The nervous system has been overwhelmed).
  • Trauma can result from real or perceived threats (Nervous system activation is the same for real and imagined threats).
  • Trauma is subjective and relative (what I perceive as overwhelming, or my capacity for solution, may be different than what you perceive as overwhelming).
  • Trauma creates a disconnect between the mind and the body. (Healing occurs when you can feel safe in your body, in the present moment - a resting nervous system state).

The next post in this series will explore the role of Adverse Childhood Experiences (ACE’s) as they relate to long term health outcomes and immediate impacts in the classroom.