Please let me know if these references/sites are helpful:
1. The Effect of Childhood Trauma on Brain Development
www.leadershipcouncil.org/1/res/brain.html
The Effect of Childhood Trauma on Brain Development: ... Memory and the Brain. (PDF) ... The Effects of Early Relational Trauma on Right Brain Development, Affect ...
2. A Key to Post-Traumatic Stress Lies In Brain Chemistry
CHILDHOOD TRAUMA AND THE BRAIN ... Trauma can alter the very chemistry and ... child’s frame of reference and belief and trust in their world and can affect the ...
4. How Does Post-Traumatic Stress Disorder Change the Brain ...
Effect of trauma on the ventromedial ... Understanding how PTSD alters brain chemistry is critical to empathize with the condition of the victims and devise ...
Dr. Mazur has already provided an excellent explanation on traumatic experiences and post-traumatic stress disorder. You are also asking about what happens in physical trauma. Depending on how bad the brain injury was, there can be a lot of alterations from changes in the blood brain barrier to major bleeding, with possible bleeding into the ventricular system etc. I will send a few references, see below.