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Scientists have used a drug to reverse the effects of permanent brain damage in mice, an advance they believe may help create a "concussion pill".
When mice are hit hard on the head they react much like humans. They have trouble forming new memories, their personality can change, they may become aggressive or confused and find it difficult to navigate in new surroundings.
Researchers from University of California, San Francisco in the US gave brain-damaged mice a drug, Isrib, a month after injury. They found that the animals could then navigate a maze just as well as their healthy peers.
"Head injury locks the brain into a stress response, shutting down undamaged cells. They sense something is wrong, and just slow things down," researchers said.
In the past this may have been useful. When you are hit on the brain and have trauma you probably do not want to go out and hunt a tiger. You want to be a bit more sedate until your capacities are back, 'The Times' reported.
Sometimes, however, the brain never speeds up again. The drug Isrib, "breaks this response - it releases the brain," researchers said.
"We can flick a reset button and make their behaviour indistinguishable from uninjured animals," Peter Walter, from the University of California, San Francisco said, adding there is hope of creating a "concussion pill".
"Normally people would have assumed they were permanently demented," Walter said.
The study was published in the journal Proceedings of the National Academy of Sciences.