Our perceptions, thoughts and experiences are the product of dynamic interactions occurring between functionally specialized regions of the brain. Thus, a complete understanding of such phenomena will by only possible once we understand how these interactions are organized and coordinated. The present thesis focuses on functional brain connectivity in the context of graph‐ theoretical network analysis to investigate so‐called small‐world networks. Recent studies have shown that functional and anatomical connections of the brain network are organized in a highly efficient small‐world manner. A small‐ world organization of the brain network implies a high level of local neighborhood clustering combined with global efficiency or information transfer. Thus small‐world networks explain how the brain minimizes wiring costs while simultaneously maximizing the efficiency information propagation.