A concussion is a mild traumatic brain injury (mTBI) that interferes with the brain's normal functioning. It affects the brain's software — a functional disturbance. Research suggests there may also be a structural injury affecting the brain’s hardware, though not detectable using current technology.
Concussion is a temporal issue. Different processes take place, some immediately (within a minute), others over time (over hours), and still others over extended time (over days).