The existence of anatomical basis of functional modularity in the brain has been postulated. Previous studies in the field of theoretical neuroanatomy claimed the segregated nature of cortical areas with their physiological functions by analyzing fiber connection data of mammalian brains. The aim of this study was to investigate, using modularity-based spectral community (cluster) detection algorithm, whether the behavioral-level circuits of Caenorhabditis elegans (C. elegans), which is the only animal that we have a complete wiring diagram of its global nervous system, can be inferred from the topology of its wiring diagram (neuro-synaptic level network) or not. We found that neurons belonging to strong clusters exhibit a hierarchical relationship with the worm's behavioral-level circuits. In addition, we demonstrate the possible existence of strong body-spanning clusters in real neuronal networks.