Nebraska” is a film about very little indeed. An old man on the cusp of senility, Woody Grant, gets a piece of junk mail telling him that he’s the lucky sweepstakes winner of $1 million. His wife, his two sons, his friends all tell him that it’s just a scam, but he’s intent on traveling from his Montana home across South Dakota to Lincoln, Nebraska — on foot if necessary — to collect his prize money. Eventually his younger son David agrees to drive him there, and off they go. They stop to visit some relatives along the way, who problematically believe Woody when he says he’s about to get rich and decide to hit him up for a slice.

That’s about it, and while it doesn’t seem like much, director Alexander Payne teases all sorts of humor and pathos out of it. Anyone who’s seen Payne’s “Sideways” will get the vibe; like that film, “Nebraska” is a road movie about a couple of guys who’ve found that life hasn’t worked out for the best and aren’t sure what to do about it. But Payne himself is from Nebraska, and while several of his films have been set there (“Citizen Ruth,” “Election,” “About Schmidt”), this one feels the most like a paean to the Midwest’s drab yet sprawling landscape and the rugged folk who inhabit it, rather like what the Coen Bros. did with “Fargo.” Walk into a bar in Payne’s movie, and the faces you see sitting around the counter sure don’t look like Hollywood extras.

Bruce Dern, who won best actor at Cannes last year and is remembered from years past for such films as 1970s sci-fi classic “Silent Running” and Alfred Hitchcock’s final film, “Family Plot,” stars as the stubborn old geezer, and it’s a performance like a black hole; most of the time he’s just there — unkempt, his beard and stringy white hair spinning off in six different directions — and often not responding coherently, but with every other performer stuck in his gravitational pull. When Woody does step up with a lucid remark, though, it always has some bite, because he’s an ornery old bastard; a scene where David (“Saturday Night Live” alumnus Will Forte, playing the straight man for a change) attempts to get him to open up over a beer is one of Payne’s best ever moments of uncomfortable humor. “Did you plan to have kids? Were you in love?” asks David earnestly. “I liked to screw,” answers Woody.

Payne considers himself a director of comedies first and foremost, but while “Nebraska” is full of great laughs — with the best coming from June Squibb (“About Schmidt”) as Woody’s equally tactless wife — it can be poignant as hell too. The way in which David hovers around Woody, helping him in and out of his car, or the concern on his face after Woody cuts his head in a fall, perfectly captures that point in time where the son realizes that the roles have reversed and he’s now responsible for the parent.

So Woody and Dave drive along, nothing much changes, and yet somehow everything does. Payne keeps a relaxed pace throughout, breaking up the various encounters on the road with musical interludes, where the camera opens up over the vast flat horizons as Mark Orton’s lilting neo-bluegrass score gives you a moment to just drift. It’s refreshing to see a director who has got it right, who can nudge a story along steadily but still give the viewer some space to breathe, to sink into that world.