Figure 1.6: The Markov blanket of a node in a directed graph. The statistics of the node s4 in the middle are dependent on the statistics of those nodes in its Markov blanket (shaded). (a) shows the interactions associated with s4 and its co-parents in the original graph. (b) shows the conditional distribution of s4 given all the other nodes in the graph. Note in particular the dependence on the co-parents s3 and s5.