The Osprey has some kind of aerodynamic devices sticking up along the top of the leading edge. This picture from the Wikipedia page of the wings rotated shows them against its silhouette:-
You can see them a little clearer on this photo shot from above, on the same page:-
Seen from above, they look like alternating slashes and backslashes, and they're clearly intended to change the flow properties in some way. But what precisely do they achieve, and how?