Areas of the brain and how they can be impacted following trauma.

From a neurological perspective, trauma can alter areas of brain functioning leading to further difficulties and long-term additional mental health issues which are secondary to the individual trauma disorder.  
  
Researchers in neuropsychology often split the brain into three distinct units; the hindbrain, midbrain and forebrain and focus is on the area of the brain affected by trauma.

  Trauma is as individual as its role is in changing neural pathways however common issues arise within the temporal and frontal lobes in areas such as the cerebral cortex, cerebrum, hypothalamus, thalamus, amygdala and hippocampus.

I intend to look further into each of these areas in relation to how they are altered by trauma in more detail throughout. I also intend to look at how this changing of neural pathways presents itself and its potential for future mental health issues and disorders. Due to trauma altering these structures, it is common to see a patient with a primary diagnosis of complex trauma also having a secondary or tertiary (etc) mental health illness.

This is nowhere near an in-depth analysis of the brain; rather than the goal being familiarisation of major brain structures and how they relate to trauma.

The temporal lobe (TL) 


The TL is found on each side of the brain (above your ears) and is responsible for hearing, memory, meaning and language as well as having a role in emotion: as the TL interprets and processes any auditory stimuli. The hippocampus is also located in the TL which results in this area forming and relaying memories.

Damage to the TL can lead to issues with memory, speech perception and language. 

The frontal lobe (FL, prefrontal cortex, PFC)


The frontal lobe is the area concerned with planning, reasoning, emotion, creativity and judgement. Any act that we purposely do (i.e; speech, problem solving) is controlled by the FL. 

Damage to the FL can result in changes in sexual habits, attention and socialization as an individual undertakes more risk-taking behaviours. A less activated PFC can be found as a response to stress and is impaired in its ability to regulate threat responses. 

The cerebral cortex (CC)


CC controls thinking reasoning and perception. it makes an individual unique, controlling traits such as human consciousness and imagination.

The cerebellum


The cerebellum controls movement and balance, but also has the title; "emotional brain" or "little brain" as it is very deep within the brain structure however makes up 10% of the total size of the brain accounting for more than 50% of total number of neurones in the ENTIRE brain.

The hypothalamus


The hypothalamus controls temper, emotions, hunger or thirst and sleep. It connects with many other regions of the brain and is involved in secretion of hormones. This structure plays an important role in the stress response which can be altered by trauma. CRF (corticotropin releasing factor) is released from the hypothalamus: mediating fear related behaviours. 
 
A change to this structure could cause a survivor of trauma to become overly fearful or less than vigilant in their behaviors which are critical in coping with an acute threat should it present itself.

The thalamus


The thalamus receives sensory information and release it to the cerebral cortex. The thalamus is also responsible for sending out information to the relevant parts of the brain that has been communicated by the cerebral cortex.

The amygdala


The amygdala controls emotions and regulates mood. Part of the limbic system; meaning it has the important role in the control of emotional responses and threat detection.

The amygdala's function is seen to be increased in individuals who have experienced trauma however smaller amygdala volume has been found in patients who have borderline personality disorder and an increased volume found with depression.

The hippocampus


The hippocampus is involved with the formation and storage of memories within the frontal lobe, those with PTSD have been identified as having a smaller hippocampal structure following a traumatic event resulting in the alteration of memories as it is the most sensitive area to effects of stress.
  Traumatic stress can be associated with lasting changes in an individual's brain structure due to an increase in cortisol and neuroepinephrine responses to subsequent stressors.
  The hippocampus however has an unusual ability to regenerate and can be altered through therapeutic approaches.

Trauma occurring at different stages of an individual's life cycle has the potential to interrupt and alter the developing brain. It is normal for the human brain to undergo changes in structure and function across an individual's life span and so in terms of trauma responses being directly linked with brain systems; there is scope and potential to alter the systems to a healthier structure.

To understand how multiple trauma can impact the brain; it would be useful to have knowledge and understanding of how the brain develops across an individual's life. 

Brain development occurs in utero and continues to develop. In the first five years, researchers found a mass overall expansion of volume; however from age of 7 to 17 years we see an increase in white matter structures and a decrease in gray matter structures with overall volume remaining the same. Through the mid part of life from the age of about 20 to 70 there is a decrease in gray matter and more so in the temporal and frontal Cortex. Trauma at different stages in life thus can have very different effects on the brain.

Symptoms of trauma manifest stress-induced changes in the brains function and structure. This is due to the nature of stress changing neurochemical systems and specific regions of the brain; resulting in long-term changes in neural pathways or circuits involved in the stress response. (1)

longer-term dysregulation of stress hormones can lead to a survivor having LOW levels of cortisol and elevated levels of the CRF. This is not always the case however in such cases of Childhood trauma, studies have shown survivors having normal cortisol and a blunted CRF (2). Early stress is associated with hippocampus alteration which may not actually manifest until adulthood.

Trauma causes memory disturbances within the brain with verbal memory deficits, dissociative amnesia and attention bias (looking subconsciously for trauma related information) as well as a reduction of neurons and volume within the hippocampus. A study researching hippocampal volume in PTSD with a veteran sample showed and 8% decrease in hippocampal volume and verbal declarative memory function deficits (3). Those survivors who progressed to having anxiety disorders also had a smaller hippocampal volume compared with survivors who had no anxiety disorder present. This shows that each subset diagnosis could actually be an indicator of changing within neural pathways. Both hippocampal atrophy and memory-based deficits reversed with treatment of SSRI paroxetine antidepressants (4). 
  Research and hippocampal volume has shown that the reduction in volume is associated with a range of traumatic related disorders however intervention and support following a traumatic event is critical for long-term outcomes. With time trauma becomes resistant to treatment and medication however the wrong response initially can also result in worsening of an individual's severity of trauma.

PTSD and trauma related disorders have a broad range of effects on the structure and function of the brain as well as memory. Common areas of the brain impacted by trauma includes the prefrontal cortex amygdala and hippocampus with cortisol and norepinephrine playing a vital part in an individual stress response and memory. With stress affecting brain areas; researchers have begun to study the effects pharmacology can have in counteracting the effects of stress and hippocampal reduction. treatments that are successful in treating PTSD have been shown to promote memory, hippocampal volume and neurogenesis. However few studies focus on complex trauma or developmental trauma with regards to any changes in brain structure. Preliminary research shows a difference between multi-event trauma and developmental trauma with regards to how the brain responds. That is the reason adding developmental trauma as its own illness would be of great importance. More research is thus required in this field in order to validate results and provide new information.

Our research group can be found here; 
https://www.facebook.com/groups/2348717965433957/?ref=share

Currently we are conducting research into the causes of trauma. I have included a link to the survey here : https://surveyheart.com/form/5f06e63b3ed8765392fe12d0

If you would be interested in taking part, please feel free. If you would like to share this study i would also welcome you to use the link, many thanks! 


References

1.  Bremmer, Vermetten; circuits and systems in stress, 2002

2.   De Bella, Dorn, et al; hypothalamic-pituitary-adrenal dysregulation in sexually abused girls, 1994

3.  Bremner, Randall, Vermetten et al, 
PTSD related to childhood physical and sexual abuse: a preliminary report, 1997

4.   Vermetten, Vythilibgam, Southwick et al, long-term treatment with paroxetine increases verbal declarative memory and hippocampal volume in PTSD, 2003

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