Dr. Sergei Kirov is a neuroscientist and Director of the Human Brain Lab at the Medical College of Georgia. He has been working with living slices of human brain tissue for years to gain a better understanding of why brain cells die from stroke or trauma. Using a two photon laser scanning microscope he can see exactly how brain cells respond to these events. In the March 2013 issue of the journal Brain Dr. Kirov published an article explaining how mild TBI kills brain cells.
Mild trauma causes blood flow constriction to astrocytes which swell up and smother neurons (the brain cells we need to think, remember, speak, and so forth). Astrocytes are support cells that help route blood and nutrients to brain cells. Neurons can die directly from the failure of astrocytes or from being stressed by bloated astrocytes. When neurons are stressed they run out of the energy they need to pump out sodium ions, pump in potassium ions and keep a proper metabolic balance necessary for their continued existence. This phenomenon is called depolarization.