title: Volumetric sampling strategies for heterogeneous brainstem nuclei.
abstract: Many brainstem nuclei are heterogeneous structures in which neuronal and glial populations are unevenly distributed, and focal normal or pathologic deviations in cell density, so-called "features," are found. Examples of features include subnuclei, focal neuronal loss, and focal gliosis. We present a statistical test that justifies an investigator's claim that a feature is present in a nucleus at a selected level of confidence after completion of a cell counting experiment. The computer program developed for the test also indicates the most probable location of the feature within the nucleus, and its most probable density and length, and potentially allows one to make comparisons of feature characteristics among cases. We also present quantitative guidelines for the selection of a sampling periodicity in a heterogeneous nucleus before a cell counting experiment. Sampling periodicity is based upon analysis of computer-generated simulations of the nucleus with features of different sizes; for each feature the probability of Type I (false positives) and Type II (false negatives) errors are examined against one another. Type II error rate is dependent upon feature length and density, acceptable Type I error rate, and sampling periodicity. Feature detection is important for devising sampling strategies in brainstem nuclei.
authors.affiliation: Division of Neuroscience, Children's Hospital, Boston, MA 02115.
authors.forename: H C
authors.initials: HC
authors.lastname: Kinney
authors.forename: C C
authors.initials: CC
authors.lastname: Meagher
authors.forename: J E
authors.initials: JE
authors.lastname: Simons
authors.forename: S W
authors.initials: SW
authors.lastname: Matthysse
mesh_terms: D001253:Astrocytes / Q000166:cytology; D001933:Brain Stem / Q000166:cytology*; D002452:Cell Count; D003198:Computer Simulation; D006801:Humans; D007002:Hypoglossal Nerve / Q000166:cytology; D007223:Infant; D009474:Neurons / Q000166:cytology; D009847:Olivary Nucleus / Q000166:cytology; D012984:Software; D013223:Statistics as Topic; D014630:Vagus Nerve / Q000166:cytology