Subsystems microarchitecture of nervous system ( Swanson & Bota (2010) ) : One of two common orthogonal ways to describe completely the nervous system (Monro, 1873). Subsystems here deal with the accurate microscopic (histological) delineation and description of gray matter regions and white matter tracts, in contrast to the topographic description of nervous system that deals with macroscopic locations in the nervous system. For the nervous system (Monro, 1783), connections and the routes they take are described in terms of gray matter regions and white matter tracts, which are formed by neuron types (Bota & Swanson, 2007), neuron parts, and molecules. An individual nervous system subsystem is a set of connections that form a complex unity with a specific function; also see systems description of body.