I'm reading a review paper. They say:
The position of an object in head-centered coordinates (that is, relative to an animal's head) can be defined along three axes: the medio-lateral (radial) axis, the rostro-caudal (horizontal) axis and the dorso-central (vertical) axis.
I'm having a little bit of difficulty understanding this coordinate system as the paper doesn't provide a picture. Usually I would think of the three axis as an x-y-z coordinate system where the rat's head is the "origin" (from a mathematical standpoint), but the terminology here seems to be a bit different, so I'd like to understand from a biologist's point-of-view how these three axes are drawn relative from a rat's head.
Paper can be found here: http://www.nature.com/nrn/journal/v9/n8/full/nrn2411.html (bottom of page 602)