Can someone explain mouse features to me?

[mxoagentjohnson]

Hey, i just recently got a R.A.T 7 (Havent used it yet) to replace my breaking cheap microsoft mouse, and i was just wondering.

Could someone explain what DPI, what Mosue Polling Rate and how these affect gaming and each other?

Thanks!

 

[mxoagentjohnson]

Does polling rate in theory actually help reduce mouse lag with VSYNC on? or is mouse lag caused by the fact the pc is running at 60fps instead of 120 on a 120hz monitor?