Jerry Cantrell

Ok heres my question, on Alice in chains record, Jar of Flies, there is a certain song called Rotten Apple. Now how the hell did Jerry get that tone on his guitar. You know if you heard it, that solo he does in the background almost the whole time. It sounds creepy and i would like to know how he get that sound. The sound is also heard on planet Caravan, by Black Sabbath, but better sounding by Pantera. Can anyone tell me how he got that tone?

First of all he has lots of treble with little mid and bass. I also think he might have some sort of octave effect on it or maybe the guitar track is doubled.