A multivariate phenetic approach to neuronal nuclei resemblances across species, with examples from three regions of cerebral cortex of a mammal, a bird and a reptile.
In order to test the assumed homology between three examples of cortical cerebral architecture corresponding to three species of mammals, birds and reptiles respectively, a method arising from the quantitative standpoint of the concept of homology has been utilized. For this purpose, data corresponding to randomly selected neurons were analysed by means of multivariate techniques such as principal component, principal co-ordinates and hierarchical cluster analyses since on each neuron a set of nineteen variables, chosen as a definition of its dendritic morphology, was measured. This method has made it possible both to discern the neuron forms which are responsible for the discrimination between the three cortical nuclei studied and to show by setting up a discriminant index, the degree of overall similarity between such nuclei. These two findings provide evidence against both the fibrous connection criterion with which some modern neurobiologists ascertain homologs and the categorical concept of homology.
Ipiña
S L
SL
Dept Matemática Aplicada, Facultad Ciencias Biológicas, Universidad Complutense Madrid, Spain.
D000818:Animals; D001717:Birds / Q000033:anatomy & histology*; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D009115:Muridae / Q000033:anatomy & histology*; D009474:Neurons / Q000166:cytology*; D012104:Reptiles / Q000033:anatomy & histology*; D013223:Statistics as Topic