pixel values of a region around a point

I am trying to get pixel values of a region around a point thru looping but its giving only the last value. how to get all these values in a single matrix.

I=imread('spot.gif'); [c r]=imfindcircles(I,[10 30]); c1=c(1,:); c2=c(2,:); for i=-3:3; for j=-3:3;

P=impixel(I,c1+i,c2+j);

end end

and if im using P(i) its giving error, subscript indices must be real positive integers or logical. can anybody tell me how to get pixel values of all possible combination from -3 to +3 region in a single matrix.