Understanding trauma, the brain and the nervous system: a medical perspective

BY DR. Vicky Onyeka, Junior Medical Doctor

For a long time, the world of medicine had been very reluctant to connect the psyche with the physical human brain.

Fortunately, in modern times, multiple studies have shown that our brains respond to every external stimulus received via the five senses.

The brain processes every single stimulus accordingly and chooses an appropriate response beneficial to us at that time.

Although, we are not aware of most of these stimuli, processes and responses. If we were, our conscious part of the brain will be overloaded. Most of it happens automatically and within our subconscious / non-conscious regions.

The aim of this two-part series of articles is to demonstrate that there is in fact science and medicine in mental health. Many bizarre and unexplained symptoms and bodily sensations people experience have a genuine cause, explanation and, thus, answer.

How the brain and nervous system work

  • Reception:
    The brain – with the nervous system – is our way of interacting with our environment. It receives information constantly from our surroundings via our afferent tissue (parts of our body which we use to receive information and send to the brain), namely our eyes, ears, mouth, nose and skin. We have the most innervation (i.e. stimulation) in these areas compared to other parts of the body, hence why they are the most sensitive and active. 
  • Processing:
    The information is sent via nerves to the spinal cord and ultimately to the brain. The brain analyses this information by linking it with past information stored as memories and innate human predispositions (instinctual information passed genetically and otherwise, such as morality, happiness, sadness, pain). This is to understand the situation occurring and its impact, to decide on an appropriate response. This function happens mostly in the parietal lobe (analysis centre), occipital lobe (visual centre) and the temporal lobes (emotional, memory and hormonal centres) of the brain.
  • Response:
    The brain responds by producing neurotransmitters (aka neurochemicals) to other parts of the brain, which stimulates neurones and the production of hormones (chemical signals). Creating and expressing the response happens mostly in the frontal lobe (socialising aka humanity centre) and is expressed via efferent target tissue (tissue that receive the response signal from the brain and express the response into the environment), which is also referred to as the somatic and autonomic nervous system: your limbs, senses, organs and the brain itself.

I must emphasize that these three over-simplified neurological functions of the brain are also affected by genetics, which influences the development potential of different areas of the brain.

Some individuals are genetically predisposed to have more developed areas for reception, processing and/or response (more innervation, for instance). These persons are more likely to have a more intense and in-depth experience and sensation to the external stimuli, otherwise known as “Highly Sensitive People”. Studies using MRI scans prove that these individuals have more blood flow and levels of activity in these areas of the brain than the average person. 

Individuals with less developed areas are not as likely to be in touch with the external stimuli and thus seem “out of touch” with life and people. For instance, sociopaths and psychopaths have been shown many times in studies via MRI scans to have less developed, absent or less active “emotional and socialising centres” in the brain.

Childhood trauma: some context

Trauma in childhood is a lot more complex as the brain is not fully developed in terms of its ability to process information or in its experience. It’s not able to process large amounts of information simultaneously, especially if there is too much variation, unfamiliarity and occurrence.

The brain thus does a few things:

  • Repression:  
    Sending the traumatic information into the subconscious – to avoid neurological overload which can overwhelm the nervous system, even to the point of causing the brain to shut down. The brain does this as it cannot cope with the sheer size and form of information, and does not know what to do with this. This is why many people do not recall significant events in their childhood (aka ‘Protective amnesia or Dissociative amnesia’).
  • Guess response:
    The brain uses every sort of information in the processing stage in an attempt to “make up” or “guess a response”, causing different surges of different neurochemicals, some of which may not be appropriate (The ratios of the different neurochemicals varies depending on the genetic predisposition of the brain, but one will be produced more than the others). This stimulates a variety of effects on the body and brain itself, some which may be contradictory to each other. 

Some neurochemicals in the brain known to affect our psyche include:

  • Dopamine: involved in addiction, motivation, perception, arousal, decision making, focus and attention, sociability; 
    • High levels of dopamine are associated with neurological hyperactivity – illusions, hallucinations (schizophrenia), addiction.
  • Serotonin: involved in appetite, sleep, learning, mood and aggression
    • Low levels cause loss of appetite, insomnia, inability to receive and retain information, low mood, higher levels of aggression or irritability (depression).
  • Norepinephrine: involved in the flight & flight response
    • Higher levels can cause hyperhydrosis, muscle tension, tremors and other symptoms of anxiety. This may also trigger panic attacks. 
  • GABA: An inhibitory neurotransmitter that slows down the nervous system, thus affecting relaxation, mood, sex hormones. A deficiency can cause agitation and low libido. Overstimulation can cause slowed actions and thoughts, lethargy, etc. 
  • Cortisol: Also involved in the flight and flight response. Most common hormone elevated in stress. Chronic elevation due to chronic stress leads to diabetes, high blood pressure, weak immune system, skin problems, musculoskeletal weakness, weight gain, slow recovery from injuries and ailments. The end stage is adrenal insufficiency.  

Fluctuant surges in different chemicals in response to fluctuant environments can encourage the development of bipolar disorder in those who are genetically susceptible. 

  • Complete brain shut down:
    This may manifest as a “sleep attack” aka narcolepsy. This is quite rare, thankfully.
  • Neurological offload:
    The brain fires off “random” neurological signals in hopes to reduce the neurological overload on itself – these random neurological signals can be sent to any efferent target tissue and produce unpredictable responses – chronic non-specific pain (polymyalgia), seizures, mutism, blindness, immobility, fatigue, inability to taste, coordinate, amongst many others. These are symptoms of conversion disorder, aka Functional Neurological symptom disorder (FNSD) which falls under somatic disorders which is a functional disorder. Functional disorders include other non-neurological disorders.
  • Partial brain shutdown / suppression
    Areas of the brain have decreased activity or control e.g. memory, vision, speech, auditory. Examples: dissociative amnesia, selective mutism, functional disorders (functional blindness, etc).

Other areas affected are the hormonal centres: the hypothalamus which is proximal to the temporal lobe and amygdala. Hormones that are regulated by these brain areas include sex hormones, cortisol, oxytocin, growth hormone and thyroid hormone dopamine. 

  1. Sex hormones (testosterone, progesterone, oestrogen) are involved in sexual and puberty development and maturity. Hence why at times, victims of trauma may seem physically, emotionally and mentally regressed compared to their chronological age. Older individuals may see pubertal delay, period irregularities and stunted growth. This is because the brain does not see these physiological functions as essential to survival and so re-directs its resources and development to other functions crucial for survival.
  2. Growth hormone is involved in the growth and development of the musculoskeletal system. This is also suppressed in prolonged trauma exposure and can cause stunting in growth and performance in the musculoskeletal system.

This is why, if someone may seem immature or unusual, one must consider if there has been trauma so significant to inhibit their all-round development and maturity.

  • Compartmentalization:
    The brain compartmentalizes all the information associated with the event, including the child’s identity associated with that time. This can manifest as a dissociation disorder aka dissociative identity disorder.
  • Dissociation:
    The brain dissociates the conscious part from the experience, and makes it recess from reality into itself, and goes into autopilot.  This is called depersonalization / derealization disorder. This is one of those “out of body” experiences and weird experiences of being aware but not in control. 

Note: The conditions I described overlap in terms of their pathophysiology (method of occurrence).

In the next part of this series, we’ll explore the symptoms of trauma and the science of recovery.


Stay tuned for Part Two of the series on medical insight into trauma!