Circuit activity/status. Could be voltage, zero point, current energy drain, electromagnetic/static interference, whatever. Granted there's no labels, symbols or anything of the sort to associate them with anything, and that's probably your point. It's just cosmetic bullshit style over substance, which is unlike me and unlike Deus Ex, so I should tread carefully. In reality they are passed values such as current energy drain, current energy : max energy, randomized fluctuation, and other nonsense. Would you like me to tag/label the bars each?