John-the-Tourist writes:
Getting information on how individual neurons fire was, until recently, nearly impossible in animals moving around because the detection devices were too delicate.  In the October 14, 2009 edition of Nature, a team of neuroscientists have figured out how to keep a mouse’s head stationary while it runs around on a Styrofoam ball that controls a virtual environment.  Keeping the mouse’s head still allows the delicate measurements to take place.  The virtual environment is created via the open source engine for the video game Quake 2.  So, in some sense, the mouse is playing a video game.  We do not yet know if mice are subject to video game addiction.
The information gleened from experiments like this will help scientists understand how brain cells work while animals navigate their environment.
The scientific community eagerly awaits the first Wii Sports playing guinea pig to see if rodents prefer baseball over tennis.
More details can be found at Wired Science (including a diagram of the apparatus)