why this value...

# set one if i achieve the decision rule
apply(asd_sel.dt, 1, function(x){
  val <- as.numeric(x[["olymp.mean"]])
  if( val >= t.unique ) adj_mat[x[["ROI_1"]], x[["ROI_2"]]] <- 1
})

why this value isn't set on the adj_mat matrix?! and why this apply shows me different prints...?

why this value...

Why not?

We need the rest of your code and some sample data to have some idea of what you are doing.