Efficient estimation of cell volume and number using the nucleator and the disector.

The nucleator allows the unbiased estimation of absolute structural quantities of suitably sampled, arbitrarily shaped structures from observations made from arbitrary points using isotropic probes. A number of time-saving modifications using the nucleator and the consequences of the modifications are studied in terms of their bias and efficiency. Using rat neocortex as an example, a description is given of how to estimate mean neuronal volume and total neuron number efficiently from only a few pairs of plastic sections with a thickness of about 3 microns.