https://www.sportscardforum.com/artic...all-headshots/

A quick snippet...

The Science of Concussions
It is really only in recent years that we have made great scientific advances in studying the human brain and its reaction to trauma. There has been considerable discussion in the scientific community about methods of prevention and what happens to the brain in the aftermath of being concussed. To date, unfortunately, there is no real method of healing, so that leaves us to focus on how to prevent the injuries and how to mitigate the symptoms one endures when going through post-concussion syndrome. An examination of what a concussion is would be appropriate here. Simply, a concussion is a brain injury caused by a sudden jarring blow that causes the brain to slam against the inside wall of the skull. This can result in a bruise to the brain, along with severing nerve endings that causes the brain to literally misfire, making even simple chores very difficult for a concussed person. Not all blows to the head will result in a concussion, but since the brain floats inside the skull any jarring blow can trigger an injury that may not meet the criteria of a concussion. The following image shows the areas of the brain that are operating when a person performs a simple arithmetical calculation, before and after a concussion:

Florida Atlantic University. Neural Basis of Cognitive Deficits Associated with Mild Traumatic Brain Injury. http://www.ccs.fau.edu/section_links...arch/MTBI.html

Enjoy the rest of it. It was a very interesting topic to research.