streamparticles in the specified region

I am using the streamparticles function to plot points along a streamline using the sample code provided in matlab help section.

I wish to limit the streamparticles to only the region of the plot that I specify. Basically I want the plots to be displayed in the region above a certain streamline of a rankine oval. I am not entirely sure how to modify the code such that only the streamparticles that start above the 2.2 mark along the y axis and below 1.8 mark on the y axis are shown. I don't want the central part.

The code I used is -

daspect([1,1,1]); 
[verts,averts] = streamslice(x,y,u,v); 
sl = streamline([verts averts]);
set(sl,'Visible','off')
iverts = interpstreamspeed(u,v,verts,.005);
streamparticles(iverts, 100,...
    'Animate',1,'FrameRate',5000, ...
    'MarkerSize',4,'MarkerFaceColor',[0 .05 0])

Currently this is what I am getting -