Which is not a cause of brain injury?

Cold exposure is not typically associated with causing brain injury in the same way that other listed conditions can. Stroke, tumors, and infectious diseases can all directly affect brain function and lead to injury. A stroke results from a disruption in blood supply to the brain, potentially causing cell death and functional impairment. Tumors can create pressure on brain tissue, disrupt normal functioning, and lead to neurological deficits. Infectious diseases, such as meningitis or encephalitis, can result in inflammation or damage to brain tissue, which may result in long-term complications.

In contrast, while extreme cold can have effects on the body, including hypothermia, it does not directly cause brain injury in the manner that the other options do. Cold exposure may impact overall health and can lead to various systemic issues, but it is not classified as a direct cause of brain injury by the same mechanisms as the other choices listed.