Way to invert mouse camera look axis?

[welbot]

I was looking through the in game options, but I didn't seem to find any option for inverting the camera axis when using the mouse. (When you hold right mouse button and look around) 
I'm used to inverted controls (pushing up looks down) and it always makes me mess stuff up when I have to deal with it the other way round, so I'm wondering if there's an option in the game that I missed, or perhaps a mod that will allow me to change that behaviour? 

[Coyote Foxtrot]

I believe in the input section of the main menu settings that shows the control axis, there will be a bubble to click on to invert the axis.

Like in this image.