Well just a couple of points:
  1. It's difficult to know which bit you mean if you just post some tab, which part of these do you mean?
  2. It would also help to know the song these are from? The tab and notation are all very well and good but without knowing what the song and band are it's difficult to say how it was played originally.

That said... it looks like that's a pretty normal alternate picked section, and I would guess that the notes in brackets are probably someone notating the harmony line really stupidly. Like I said though, need to know the song and where in the song it is to be able to say anything for sure.
R.I.P. My Signature. Lost to us in the great Signature Massacre of 2014.

Quote by Master Foo
“A man who mistakes secrets for knowledge is like a man who, seeking light, hugs a candle so closely that he smothers it and burns his hand.”