APPLICATION OF PRINCIPAL COMPONENT AND CLUSTER-ANALYSIS TO THE STUDY OF THE DISTRIBUTION OF MINOR AND TRACE-ELEMENTS IN NORMAL HUMAN BRAIN

A data set with the K, Ca, Mn, Fe, Cu, Zn, Se, and Rb concentrations for 46 brain structures of gray, mixed, or white brain matter was subjected to VARIMAX rotated absolute principal component analysis (APCA) and hierarchical cluster analysis. APCA indicated that most of the K, Cu, Zn, Se, and Rb is present in the intracellular brain fluid. Calcium is mainly associated with the extracellular fluid, while most of the Fe is found in the solid brain fraction. Both the intracellular fluid and the solid brain fraction contribute to the Mn content to a considerable degree. Hierarchical cluster analysis showed that the brain regions conglomerate in two main clusters. All gray matter structures are included in the first cluster; the second cluster comprises all white matter areas. Furthermore, structures involved in the same physiological function or morphologically similar regions often conglomerate in the same subcluster.