Network modeling is gaining impetus in system biology and in cell biology.Especially in neurobiology and immunology, novel data based on transcription factor analysis and gene expression profiling have raised our understanding of complex regulatory and developmental pathways.For instance, siganaling networks that allow for distributed decisionmaking in neurite outgrowth and neuronal differentiation have been studied in the group of Bromberg, Maayan and Iyengar (2005, 2008).In another example, developing cellular networks like the mononuclear phagocyte system (MPS), with special focus on the role of resting and activated dendritic cells, have been recently elucidated using gene expression profiling in healthy individuals, and in autoimmune and psychiatric disorders (Drexhage et al., 2010).