Pain, Trauma, & Changes in the Brain

A examination of the pain, trauma, and long-term effects on the brain. 

Brain Chemistry

A quick synopsis of the chemicals of the brain.

Chemicals Of the Brain

Dopamine - The reward or motivation chemical, helps foster feeling of well-being. Regulates memory and motor control. Low levels of dopamine are often associated with addiction.

Epinephrine - Responsible for regulation of the sympathetic nervous system response. Causes an increase in heart rate, force of heart contraction, and bronchodilation. 

Norepinephrine - Assists epinephrine in sympathetic nervous system response. Peripheral vasoconstrictor and dilation of the coronary arteries. Mediates arousal.

Oxytocin - Increases cognition, social functioning, and memory. Inhibits the stress induced HPA-Axis activity. (Lower levels in individuals with social anxiety disorder).

Endorphins - Decrease pain perception and contribute to a general feeling of well-being (natural opioids).

Serotonin - Helps modulate the responses of neurons to dopamine and epinephrine.

Melatonin - Manages circadian rhythms and is inhibited in response to high levels of dopamine. 

GABA - Inhibits excessive brain activity that can lead to excessive negative thinking. Regulates the levels of dopamine, epinephrine, norepinephrine, and serotonin. "Nature's valium".

5-Hydroxytrytophan - Precursor for serotonin production.

Match the following brain chemicals to their action:

  • GABA
    "Nature's valium"
  • Epinephrine
    Fight or Flight
  • Dopamine
    Regulates reward/pleasure
  • Serotonin
    Regulates neuronal responses to epinephrine and norepinephrine
  • Melatonin
    Regulates sleep/wake cycle

What is pain?

Physical Pain Defined & Explained

Physical Pain

Understanding & Defining Pain

Pain (noun) - as defined in Webster’s Dictionary

  • Physical suffering or distress, as due to injury, illness, etc.
  • A distressing sensation in a particular part of the body: a back pain.
  • Mental or emotional suffering or torment: I am sorry my news causes you such pain.

Acute & Chronic Pain

When we think of pain, it is typically physical pain that comes to mind so that is where we will begin. Physical pain can be divided into two categories: acute and chronic. Acute pain is an immediate response to injury or illness, it comes on quickly and often without warning. Acute pain lasts from time of injury to ~12 weeks, time for healing. Chronic pain persists far beyond the time of healing from trauma. Pain signals continue to travel through the nervous system for weeks, months, even years after initial trauma.

Role of the Brain in Pain

The somatosensory cortex processes the type and location of the pain. The limbic association area emotionally processes the pain. The motor cortex organizes the muscles necessary to react to the pain.

Somatosensory Cortex

The sensory cortex, located in the front portion of the parietal lobe, receives information relayed from the spinal cord regarding the position of various body parts and how they are moving. This middle area of the brain can also be used to relay information from the sense of touch, including pain or pressure which is affecting different portions of the body.

Motor Cortex

This helps the brain monitor and control movement throughout the body. It is located in the top, middle portion of the brain.

These creepy little guys are called homunculi and are a representation of the sensitivity of a particular area of the the body or motor control of a particular area of the body. Think about how sensitive your fingertips are but how, if you accidentally sit on your sunglasses, you may not even feel them.

Role of Spinal Cord in Pain

The spinal cord is a conduit for sensory and motor signals; sensory to the brain and motor away from the brain. In addition to transmitted information to and from the brain, the spinal cord also coordinates some reflex actions. This is an example of spinal cord (this is likely from the thoracic region). You can see how much of the white matter (outer areas) is devoted to sensory input. Within the gray matter (the butterfly-shaped part) are synapses where sensory and motor nerves communicate in some way.

Role of Sensory Nerves in Pain

Sensory nerves (afferent) travel toward the brain while motor nerves (efferent) travel away from the brain (motor nerves assist in the response to pain). Normally sensory nerves involved in transmitting pain signals will quiet down quickly – think about the last time you stubbed your toe, it hurt like crazy but calmed down after a few minutes (unless you broke something).

There are three types of sensory nerves: “A-delta fibers”, “C fibers”, and "A-beta fibers".  A-delta fibers are the first to activate and transmit electrical signals quickly at 40 mph. C fibers are slow and continuous, traveling at a speed of 3 mph (McGonigal, 2009). A-beta fibers are super sonic fast, traveling at up to 200 mph and interpret pressure and touch. C fibers are most likely the culprits of chronic pain, assisted by A-beta fibers that refuse to inhibit the pain signals.

Types of Pain

Nociceptive - Occurs when the body's tissues are damaged (somatic and visceral)

Inflammatory - Causes the secretions of substances that lower the pain threshold. Can be temporary or can occur in chronic illnesses.

Neuropathic - Caused by injuries or diseases in the nervous system. Pain can be the result of damage to the nerve or pressure on the nerve.

Sources of Pain

Somatic - 1) Superficial, cutaneous, or peripheral pain - arises from skin and muscles or 2) Deep - arises from joint receptor tendons and fascia.

Visceral - Nociceptors respond to mechanical stimuli; pressure, tissue damage, chemical stimulation.

Neuropathic - Arises from functional changes occurring in the damaged nerve.

Psychosomatic - Psychic response to physical or emotional pain.

Pain Receptors

We have tons of sensory receptors located all over the body and different classes of receptors have different functions. Nociceptors are located throughout the body and will respond to painful sensations and injury. The severity of the injury will impact the type and amount of chemical released. Each of these chemicals (things like arachidonic acid – sounds like arachnid HAHA – and lactic acid) will elicit an action potential. What is an action potential? – That is a whole different lesson but basically, an action potential causes a change in the voltage (by shifting the concentration of ions such as Sodium, Potassium, and Calcium) of a tissue leading to some change in the tissue. 

(For more on Action Potentials see - it is a long video but good explanation).

Types of Nociceptors

Mechanical (pain, pressure & touch)- Strong pressure or sharp objects

Thermal (hot & cold)- Extreme heat (above 113 degrees F) or extreme cold (will vary)

Chemical - Extremes in pH, environmental irritants, noxious chemicals

Polymodal  - Respond to a combination of mechanical, thermal, and/or chemical

Pain Pathway

Sensory nerves in the skin detect some change in the environment (extreme heat for example) and send a signal through a peripheral nerve to the spinal cord, thalamus, and finally the primary somatosensory cortex where the sensation is interpreted.  Following interpretation, the primary motor cortex sends a message to help the body respond to pain or the somatosensory cortex sends an inhibitory signal to modulate the pain.

*Thalamus – Responsible for sensory perception and regulation of motor functions.

The physical and energetic manifestations of trauma.

Neurologic Manifestations of Emotional Trauma


A number of changes occur in the brain in response to chronic pain. The prefrontal cortex, cingulate gyrus, and insula exhibit a decrease in the volume of their white matter and in their secretion of natural opioids. The thalamus will exhibit a decrease in gray matter which leads to a decrease in the amount of GABA released (GABA is "nature's valium". The prefrontal cortex and cingulate gyrus also exhibit an increase in localized inflammation. Anxiety, depression, and insomnia are positively correlated to pain. 


Depression is characterized by overwhelming feelings of sadness, helplessness, hopelessness, etc. that last beyond a reasonable amount of time and are found in combination with things like lack of interest in most activities, insomnia, or thoughts of suicide. Although it is commonly accepted that depression results from an imbalance of the brain’s neurotransmitters, there is not a neurotransmitter solely responsible for depression. There are some common chemical culprits including Norepinephrine, Serotonin, Dopamine, and Mono-Amine Oxidase. Serotonin is a neurotransmitter that is directly involved in the regulation of mood and in the perception of pain. Mono-Amine Oxidase is a key participant for the inactivation of neurotransmitters.

Norepinephrine and Serotonin act directly upon structures in the Limbic System to decrease the feeling or intensity of pain. If levels of Norepinephrine, Serotonin, and Dopamine are increased in the CNS, transmission of signals through pain pathways will decrease. A simple way to look at this is that decreases in the neurotransmitters that lead to depression can also lead to increased pain. Have you seen the commercial for Cymbalta that claims “depression hurts”? Now we know that there is truth in some advertising.

Post-Traumatic Stress Disorder

PTSD involves the intrusive recollections of a traumatic event and often results in a state(s) of hyper-arousal. Studies have shown that individuals with PTSD experience an over-reactive adrenaline response, which causes deep imprinting of memory associated with the fear they felt during that trauma. Three areas of the brain undergo significant changes as a result of PTSD – amygdala, hippocampus, and medial frontal cortex. Activity in the amygdala increases overall, but goes through the roof when a PTSD patient is exposed to triggers. In fact, patients with extreme PTSD will exhibit hyperactivity of the amygdala in response to events unrelated to their trauma. 

I am sure you remember that the hippocampus is responsible for memory functions – properly categorizing memories so that they may be called on later to help inform a response to a new threat. In PTSD patients, the hippocampus is markedly reduced in volume and this leads to an inability to respond to new situations effectively.

The prefrontal cortex is responsible for the regulation of emotional responses, especially fear, triggered by the amygdala. The prefrontal cortex in PTSD patients will exhibit a substantial decrease in its volume. Such a decrease is problematic because the prefrontal cortex will inhibit amygdala generated fear responses.

In addition to the structural changes in the areas of the limbic system just discussed, research shows that parts of the endocrine system are also adversely affected – specifically the HPA Axis. If you remember, cortisol levels rise during a sympathetic nervous response. Researchers have found that PTSD patients may display either high or low levels of cortisol (the difference in cortisol levels may be due to a number of things). One study of Vietnam Combat Vets had higher cortisol levels and another study of Croatian Combat Vets had fewer cortisol receptors- this could lead to higher circulating cortisol (Delaney, 2013). There are many factors that contribute to the varying degrees of cortisol dysregulation so just keep in mind that the aforementioned are generalizations.

The long-term overproduction of cortisol can lead to shrinkage of the hippocampus thereby impacting the patient’s “ability to discriminate between past and present experiences or interpret environmental contexts correctly” (Wlassoff, 2015).

Generalized Anxiety Disorder

Generalized anxiety is excessive worry or stress with no discernible trigger. Physiologically, anxiety is a Sympathetic Nervous System/Fight or Flight response. Increased stress leads to increased Cortisol and Norepinephrine and ultimately a decrease in GABA. It is generally accepted that GABA and Serotonin play a large role in anxiety. When GABA and Serotonin levels are low the feeling or state of anxiety intensifies.


Most of us have experienced at least one night of insomnia and it was not fun. The next day at school or work was riddled with grumpiness, an inability to focus, and probably the waxing and waning of feeling ill. Let’s first address the chemical culprits that influence sleep. Melatonin and cortisol help to regulate our sleep/wake cycles – melatonin is associated with sleep and cortisol is associated with stress. Melatonin is released from a gland called the Pineal Gland. In humans this gland is tiny and located deep inside the brain but in other vertebrates, such as reptiles, the Pineal Gland (actually the Pineal Body) is located on the top of the head and exposed to the sun. Humans do not need such an external clock – we have our smart phones. Melatonin is regulated by Norepinephrine (Adrenalin) and is released in response to changes in light/dark as sensed by photosensitive receptors.

A good example of cortisol in action can be noted in hibernating animals like Sandy the Squirrel from Spongebob Squarepants. Sandy, a once thin and spritely young squirrel, packed on what probably amounted to six additional squirrels in preparation for winter. Cortisol prepares the body for the stress of hibernation. How is that related to sleep and insomnia? Great question! The relationship of Cortisol to sleep is complex but, in essence, when the body is under stress (physical, emotional, any type of stress) Cortisol activates different sets of receptors including Norepinephrine (Adrenaline) receptors. See the connection? It is a viscous cycle.

GABA is also involved in our sleep cycle because activation of GABA receptors will induce sleep. Melatonin increases GABA’s effectiveness. Pretty cool right? Melatonin, Cortisol, and GABA have been shown to antagonize the neurotransmitters that are associated with wakefulness (Norepinephrine is one).

Koshas & Samskaras

The Koshas

The Koshas are the sheaths of our being, often described as similar to a Russian or Matryoshka doll or as layers of lampshades on top of our inner light. The journey of yoga begins with the outermost Kosha (Annamayakosha) and moves inward. Yoga Therapists apply the Pancha Maya Kosha Model to heal physical and emotional ills through the reconnection of the individual to their whole self. The Koshas are “different, beautiful manifestations of our essential human nature” or Atman (Yoga U, 2011).

Atman – or self – “unbound universal Oneness of all that exists” (Yoga U, 2011). “I am not this body, I am not this mind, I am something more” (Manorama).

Annamayakosha – or physical body - is the layer with which we are most familiar, the layer where we spend most of our attention focused on its sensations. It is the place where we first feel pain or notice injury and it is the first focus of attention when engaging in a physical practice or asana.

Pranamayakosha – or energy body – is the life force and breath is the most physical expression of prana. Breath and energy are the next to come into awareness through asana. We store trauma and pain energetically. Think about PTSD - what happens to the breath, to the nervous system?

Manamayakosha – or mental-emotional body – is the layer of our being expressed as mind, emotions, and feelings. What is our emotional attachment to pain? How do we differentiate emotion and pain?

Vijnanamayakosha – or wisdom body – is part of the subtle body and is associated with ego consciousness. The higher wisdom associated with Vijnanamayakosha – the reflection of deeper insight into our true self.

Anandamayakosha – or bliss body – is the most difficult to quantify or qualify as it is the most subtle of the subtle bodies. The Ancients viewed Anandamayakosha as an unbound, blissful state of peace, joy, and love. Anandamayakosha is unaffected by the fluctuations of physical and emotional upheaval but few of us have a relationship with this Kosha.

The goal of yoga therapy is to heal through reconnection to the Koshas using a yoga practice designed specifically for the individual and ailment.

Green Lotus Yoga has a great explanation of the Koshas and mental disorders. 


Samskaras are impressions in the mind that are imbedded through repetition – positive or negative. We should encourage positive samskaras as they will lead to peace. It is the negative Samskaras that need to be broken.

“In some ways the negative samskaras are like an addiction. But instead of being addicted to a substance you get addicted to a particular emotional state that leads to suffering and pain. The samskaras have a familiarity to them and even though they lead to suffering it is also somehow all you know as life. Their familiarity is also their temptation because the pattern is so well established and you are so attached to its righteousness that it actually hurts to let them go. The more you unknowingly let the negative samskaras fuel your life course the deeper they pull you into the dark spiral. The practice of yoga offers what is said to be the only way out. Instead of fighting them from an antagonistic place the practice of yoga seeks to burn through the samskaras with the light of pure awareness. This is done with actual physical and spiritual practice that cultivates the fire of purification, known as agni in Sanskrit. Once the inner agni is ignited it has the power to literally fry the negative samskara almonds until only their shell is remaining and they no longer have the ability to grow and bear their painful fruit” (McGregor, 2011).

How does our physical body connect to our energetic body? In other words, how does trauma effect us on an energetic level?