Let's take a sample undirected graph.
What nodes are connected to node 51?
Let's plot the graph then highlight node 51 and its neighbors in the plot with large red stars instead of the small blue circles of the rest of the nodes.
highlight(h, [51; N], 'MarkerSize', 12, 'NodeColor', 'r', 'Marker', '*')
We can see that each of nodes 49, 52, and 55 are indeed connected to node 51.