The stomatogastric ganglion (STG) is a much studied ganglion (collection of neurons) found in arthropods and studied extensively in decapod crustaceans. It is part of the stomatogastric nervous system. The stomatogastric ganglion (STG) is a much studied ganglion (collection of neurons) found in arthropods and studied extensively in decapod crustaceans. It is part of the stomatogastric nervous system.