Figure 2.

Potential triggers of the immune response in mild TBI. (A) Physical forces lead to stretching of axons, axonal injury and glial activation. (i) Schematic representing a neuron with its myelinated axon surrounded by glia in the healthy brain. (ii) Represents the stretching of axons due to physical forces during mild TBI and the subsequent glial activation (iii) Key–indicates glial subtypes hypothesized to be activated after axonal stretching. (B) Diffuse blood-brain barrier (BBB) in the brain after concussion leads to extravasation of harmful molecules to the parenchyma. (i) Schematic shows a coronal section of a human brain with representations of diffuse BBB breakdown after mild TBI (brown areas). (ii) Enlarged image shows compromised cerebral blood vessel leaking molecules that may trigger inflammation and glial activation.