Get neighbours of an element in matrix

Hello,

Is there some easy way to get all the pixels of an element from a matrix?

For example. given the following matrix:

M=[0  0  1  1; 
   1  0  0  1;
   1  0  0  1;
   1  1  0  0];

the neighbours of M(1,1) are 0 and 1 ,the neighbours of M(1,2) are 0 0 and 1, etc

What I want to do with this information: M is a "maze matrix" where 1 is wall and 0 is a valid path. From this matrix I want to create an adjacency matrix(where the 0 elements from M will be the nodes) to perform some search algorithms.

I am gratefull for any idea. Thank you!

[dpb]

Given an i,j it's simply i+/-1,j+/-1 keeping track of boundaries so if i,j --> 1 or end only have the + or - side, respectively.