It is not guitar initially. It is a clavinet and maybe a Mu-tron autowah or Electro-Harmonix Mini Q-tron. My Google research says this tune is Funk.
http://www.youtube.com/watch?v=WryUOXo9sfM
This link, sounds, get a bit crazy.
Interesting anyway and I bet it can be mimicked using a guitar and effects pedals.
An "envelope follower" or "envelope filter" is also mentioned. As well as a compressor and a wah-wah pedal.
More links later.
I am sure somebody here to GuitarTricks can elaborate more, concerning this how-to, than my feeble efforts. :eek:
And maybe this needs to be posted in the more advanced forums, for members only, maybe with a Funk style instructor.