Prediction of the variance of stereological volume estimates from systematic sections using computer-intensive methods

Basic quantitative morphological methods applied to the central nervous system

Generating numbers has become an almost inevitable task associated with studies of the morphology of the nervous system. Numbers serve a desire for clarity and objectivity in the presentation of results and are a prerequisite for the statistical evaluation of experimental outcomes. Clarity, objectivity, and statistics make demands on the quality of the numbers that are not met by many methods. This review provides a refresher of problems associated with generating numbers that describe the nervous system in terms of the volumes, surfaces, lengths, and numbers of its components. An important aim is to provide comprehensible descriptions of the methods that address these problems. Collectively known as design‐based stereology, these methods share two features critical to their application. First, they are firmly based in mathematics and its proofs. Second and critically underemphasized, an understanding of their mathematical background is not necessary for their informed and productive application. Understanding and applying estimators of volume, surface, length or number does not require more of an organizational mastermind than an immunohistochemical protocol. And when it comes to calculations, square roots are the gravest challenges to overcome. Sampling strategies that are combined with stereological probes are efficient and allow a rational assessment if the numbers that have been generated are “good enough.” Much may be unfamiliar, but very little is difficult. These methods can no longer be scapegoats for discrepant results but faithfully produce numbers on the material that is assessed. They also faithfully reflect problems that associated with the histological material and the anatomically informed decisions needed to generate numbers that are not only valid in theory. It is within reach to generate practically useful numbers that must integrate with qualitative knowledge to understand the function of neural systems.

Synaptic contact number and size in stratum radiatum CA1 of APP/PS1DeltaE9 transgenic mice

Synaptic changes occur early in the course of Alzheimer's disease and are key to understanding the initial events in associated neurodegenerative processes. The quantitative analysis of synaptic morphology in transgenic mouse models of Alzheimer's disease can provide important insights into these processes. To this end, the total number and the distribution of the diameters of synaptic contacts in the stratum radiatum of the CA1 region of the hippocampus of 12-month-old APP/PS1DeltaE9 transgenic mice and wild type littermates have been evaluated by applying design-based stereological methods to material prepared for electron microscopy. Although there were no differences in the size of the synaptic contacts, the total number of synaptic contacts was significantly larger in the transgenic mice, suggesting that the transgenic effect at this age is synaptotrophic and that the presence of amyloid plaques and an elevated Abeta42/40 ratio are not necessarily detrimental to populations of synapses. The potential of this type of data in evaluating synaptic changes related to Alzheimer's disease is discussed and the methodology described in detail.

Efficient quantitative morphological phenotyping of genetically altered organisms using stereology

Genetically modified organisms present the challenge of quantifying structures and functions in organs, tissues and cells. Morphological investigation is greatly facilitated by taking sections in MRI, CAT scanning, histological preparations or EM, and powerful unbiased quantitative tools called stereology can use these sections in a sampling based approach to measure volume, number surface and length. Stereological tools have become methods of choice in the fields of neurobiology, nephrology and cell biology and allow accurate unbiased description of intact organs, tissues, cells and organelles. Stereology has yet to be applied widely in the field of transgenics. Here I provide an overview of stereological methods and explain how they represent a powerful addition to the transgenic biologists armoury of techniques.