Local estimators of size in stereological studies

There are two general categories of stereological methods, global and local. Global stereological estimators include estimators of total volume, surface, length, and number. Local estimators can be used to estimate the volumes or surfaces of single objects and, thereby, the distribution of object sizes or the mean size of objects within a population. Two local estimators that have proved to be of practical value for measuring the volume of cells in neurobiological studies are the nucleator and the rotator, which are the focus of this article. Variants of the nucleator can be used for estimating object number, object surface, and the spatial distributions of objects.