On this animation, you can see a proton (in magenta) coming from the
right and an electron (in blue) coming from the left. The proton is made
up of three quarks (Green, red and blue) and as the phenomena that interests
us occurs t the quarks sclae, we can see the proton just as a group of
quarks.
The electron hits one of these quarks. The three quarks are scattered
into a direction whereas the electron is scattered in another. As the particle
that made the interaction between the electron and the quarks was neutral,
this is called a Neutral Current Deep Inelastic Scattering.
(click here to see this process in vrml)