Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Concussion ?
    ### Response:
    A concussion is a type of brain injury. It's the most minor form. Technically, a concussion is a short loss of normal brain function in response to a head injury. But people often use it to describe any minor injury to the head or brain.    Concussions are a common type of sports injury.
    