Trauma and the Brain ...

... A brief look at how trauma can cause physiological changes in brain structure and chemistry

By Jodi S. W. Campbell, MS, Supervisor of Public Education, Clinical Training and Development, KidsPeace Institute

Approximately six million children are referred to child welfare agencies due to suspected child abuse in the United States annually, according to 2008 CDC statistics. Such childhood trauma has profound and often prolonged effects. Trauma, however, comes in other forms besides child abuse, and some of the most concerning of our times include chronic and systemic community violence and the threat of war and terror. A large proportion of children receiving services are victims of trauma in some way. It is imperative that professionals working with children understand the increasing pressures facing youth today. Furthermore, it is our responsibility to understand their circumstances and the potential problems that may be related to their traumatic experiences.

Sometimes, traumatic events are isolated and short-lived. These are often followed by a period of relative stability during which there is no additional trauma.  For events like these, it is normal for a person to experience transient trauma symptoms (immediate or delayed onset) such as disrupted sleeping and eating patterns, for a temporary period of time. In contrast, childhood trauma, severe personal trauma and/or prolonged abusive or traumatic conditions can have far more troubling and long-lasting effects.
There are three overall effects of childhood trauma. The first two, developmental stagnation and behavior problems, are both often and thoroughly discussed. But we must remember that there are also distinct physiological changes, particularly in a child’s brain structure and chemistry, which occur in the case of childhood trauma. Some of what is happening developmentally and behaviorally has its roots deep in the limbic system. Professionals who are working with traumatized youth need to understand the basics of these changes in the brain.

Lack of attachment in infancy can result in physical structural damage on the amygdala and limbic functions, as seen in lesion studies. Childhood trauma in the form of neglect and/or abuse can cause neurobiological changes in the amygdala, septal nuclei and hippocampus. Studies show that these areas are  stunted and smaller, and, depending on how other areas of the brain are affected, this can have wide-ranging effects, according to Dr. R. Joseph. Infants exposed to extreme levels of arousal (corticotropin, noradrenaline, adrenaline levels in the brain) – too low in case of neglect, too high in case of abuse – experience an extended period of negative emotional state, overall disorganization and the de-regulation of homeostasis. This was discussed in studies by A. Schore in 2001 and M. Solomon and D. Siegel in 2003.

“The single most significant distinguishing feature of all nervous tissue – of neurons – is that they are designed to change in response to external signals,” wrote Bruce Perry, et al., in a 1995 article in Infant Mental Health Journal. This is what allows the organism to survive, and it is also the reason why trauma can damage structures/processes in the brain. Research shows that neurochemical changes in the brain occur as a result of trauma and as evidenced in autonomic or behavioral symptoms such as elevated heart rate, changes in blood pressure, changes in norepinephrine and epinephrine levels, the storage of emotional memories and behaviors associated with fear and anxiety, according to E. Osuch et al., in 2004. Epinephrine levels in cooperation with the amygdala assist in the storage of intensely experienced memories in the hippocampus.

Implicit memories (those that are difficult to describe but are easily “felt” or “known”) are stored differently from regular memories (those that can be recalled easily and told as a story) and appear to be stored in different sides of the limbic system, J. Bacon explained in June 2008. Traumatic memories are often stored as implicit memories, especially those that occurred early in life. The amygdala is involved in the process of how these memories are categorized and stored. Exposure to trauma (particularly chronic exposure) not only has an effect on emotional regulation processes in the brain, but also on the ability to process the memories of those events. The unnatural storage of traumatic memory has an impact on one’s ability to handle future exposure to adverse situations. The circuits in the brain are less connected to the frontal lobes, where thinking and considering can mitigate the emotional reaction, leaving the amygdala on its own to evaluate the threat, J. Bacon added. Without the mitigating effects of executive functioning, the limbic system activates fight/flight response in the brain stem, causing an inability to regulate or cope with an overwhelming flood of emotion. The differences between a typical response in the brain to stimulus and the responses of a traumatized brain include:

Normal Stimulus Response vs. Trauma Reaction
Information comes into the brain from various sensory organs and usually enters the Thalamus region. The Thalamus asks itself, “Is this a threat?” The Prefrontal Cortex and other cortical, or “thinking” areas of the brain, then considers this new information and asks itself, “Have I ever experienced this before? What is the best thing to do? What might the consequences be?” After processing the information, the Prefrontal Cortex sends a signal to the Amygdala, which provides a measure of emotional output that is appropriate, based on the analysis of the Prefrontal Cortex. This experience is then carefully stored in the Hippocampus. The brain stem may never be activated at all (or minimally activated) depending on the experience.

Reaction to Stimulus in a Traumatized Brain
Information comes into the brain from various sensory organs, and the Thalmus assesses if there is a present threat. Immediately, things begin functioning differently than in a typical brain. Past trauma experiences trigger a trauma reaction in the brain, which causes the Thalamus to interpret even small losses or rejections – losing a shoe, being asked to do a chore, being denied a snack – as a new traumatic event. Once the Thalamus has interpreted the experience as a trauma, the Amygdala shifts into overdrive. The Amygdala has a disproportionate fear/emotional response to the experience and sends signals to the Brain Stem. Consequently, the individual gets a dose of cortisol and adrenaline. Palms may sweat, or the person may feel shaky. He experiences a fight or flight urge. Around this time, we may see some troubling behaviors such as impulsive decisions, verbal or physical aggression, self-harm, etc. The reason is that the Prefrontal Cortex was skipped. The memories of this event can be foggy and stored erratically in the Hippocampus. If the Prefrontal Cortex is involved at all, it may be after the crisis is over, when the child thinks about what just happened.

Food for Thought

During an actual traumatic event, the brain reacts abnormally to protect the individual. In this case, the brain is interpreting every-day stressors as major threats due to the physiological changes that occurred in the brain during prolonged periods of abuse/trauma. This explains the hyper-arousal typically seen in traumatized youth. It is becoming increasingly clear that trauma must be a key consideration in the treatment of youth who have been exposed to abuse, neglect, abandonment and other traumatizing circumstances. Clearly, treatment should be developed keeping the physiological effects of trauma on the developing brain and understanding how those changes are linked to developmental and behavioral problems in mind. Trauma-informed care must include education for professionals on these fundamentals so that we do not inadvertently fuel the trauma reaction. Instead, we should help to maintain normal levels of homeostasis in the brain during stressful situations.

Carlson, N. R. (2007). Ninth edition physiology of behavior. New York, NY: Pearson A and B.

Center for Disease Control. (2008). Reported child maltreatment victims. Retrieved on September 15, 2008 from

Joseph, R. (1999). Environmental influences on neural plasticity, the limbic system, emotional development and attachment: A review. Child Psychiatry & Human Development, 29(3), 189-208. Retrieved May 18, 2008 from PsychINFO database.

Osuch, E., Ursano, R., Li, H., Webster, M., Hough, C., Fullerton, C., et al. (2004). Brain environment interactions: Stress, posttraumatic stress disorder, and the need for a postmortem brain collection. Psychiatry: Interpersonal and Biological Processes, 67(4), 353-383. Retrieved April 19, 2008 from the PsycINFO database.

Perry, B., Pollard, R., Blakley, T., Baker, W., & Vigilante, D. (1995). Childhood trauma, the neurobiology of adaptation, and ‘use-dependent’ development of the brain: How ‘states’ become ‘traits.’ Infant Mental Health Journal, 16(4), 271-291. Retrieved April 19, 2008, from PsycINFO database.

Schore, A. (2001). The effects of early relational trauma on right brain development, affect regulation, and infant mental health. Infant Mental Health Journal, 22(1), 201-269. Retrieved April 19, 2008 from the Psych INFO database.

Solomon, M. F., Siegel, D. J. (2003) Healing trauma: Attachment, mind, body and brain. New York, NY: W. W. Norton and Company.

Jodi Campbell, MS, is the KidsPeace Institute Supervisor of Public Education, Clinical Training and Development, graduated from Cedar Crest College in Allentown, PA, and has more than13 years experience working in children’s mental and behavioral health. She has a broad range of direct-care experience with children ages 4-21 with various diagnoses in short-term and long-term settings and is currently pursuing a doctorate in Psychology from Capella University. For the past 10 years, she has been teaching and developing curriculum for direct care and clinical staff in over 25 areas of instruction related to children’s developmental and behavioral health and Life Space Crisis Intervention. Jodi has been invited to speak at local, regional and national conferences on these and other topics relating to the mental health profession.