What addictive retro video game was proven in an academic study to thicken the brain’s cortex and increase cognitive efficiency?

The answer is: Tetris. Researchers from Mind Research Network in Albuquerque, New Mexico, combined brain imaging technology with Tetris to find out if the classic game increases gray matter. Their research led to the conclusion that playing Tetris does, in fact, lead to a thicker cortex and may also boost brain efficiency. It really gives a whole new meaning to the idea of having mental blocks.Source