Brain activity during television commercials

This takes a couple of clicks, but is worth watching. Go to http://www.sandsresearch.com/ and click on "Examples" and then "2009 Super Bowl Ads and Rankings", then click on one of the ads (the Potatoheads were the most popular). You'll see the ad play and six synchonized views of brain activity, as well as graph of overall interest? activity? I"m not quite sure what they are measuring, I think they are calling it "sustained power level"?