When you say, "there is a school of thought which embraces the idea that the universe is senseless" the first idea that springs to mind is existentialism[0]. Are you talking about existentialism? You mention Nietzsche, he (along with Kierkegaard) are claimed to be the fore-runners of existentialism - the idea that life has no (intrinsic) purpose, senseless in the meaningful sense.
Their claim is that one can give meaning to life by imposing or constructing a meaning or a purpose of ones own. I think it would be a stretch to equate this purposeful overcoming of the futility and the absurd with the general pattern recognition and construction that the mind involuntarily engages in moment to moment.
Postmodernism, if it is anything, is the rejection of or going beyond the project of modernism (the clue is in the name). Modernists still believed in grand projects, ideals, and narratives - for instance, the implicit idea of progress. You could say that postmodernism paradoxically rejects over-arching grand narratives and in a way claims to bring to an end the grand intellectual epochs we've had from the renaissance onwards through the enlightenment and finally arriving at modernism. I've yet to come across a satisfactory account of postmodernism beyond the one I've just relayed.
[0] http://plato.stanford.edu/entries/existentialism/