Dimensional analysis of selected linear and curved measurements of human and baboon brains

Abstract

Brains of primates show morphometric differences that may be influenced by the process of functional complexity, evolution and adaptation. Comparative topographic measurements of the primate brains have been used to explain functional and evolutionary trends between the species and to highlight differences in salient functions. Variations in selected linear measurements of the human and baboon brains have demonstrated functional complexity. Some neuro-pathological conditions of the brain may show characteristic morphometric changes. Selected dimensional linear and curved measurements of 4 human and 4 baboon brains from the superior, inferior and lateral aspects were analyzed using ratios to evaluate variability in the morphology of the brains. The ratios for the same species (linear vs curved) provide the extent of the curvature on that measurement. This could be interpreted that more curving suggests more neurons and greater volume. With inter-species ratios; a bigger value implies a higher density of neurons or greater volume for the aspect under consideration. Intra-species co-efficient of variation comparison indicates that curved measurements had a higher variability than the linear in both species. Comparison of symmetry in terms of ratios of both linear and curved measurements indicated no significant difference between hemispheres for both species. There was similarly no significant intra-species difference in terms of curvature between the left and right aspects, but the measurement landmarked by summit of central sulcus and inferior temporal gyrus showed the highest difference in curved measurements. This study provides baseline data for certain morphometric measurements that may be used to assess pathological changes in brain disorders as found in imaging studies. Ratios may also be used to show structural, functional and evolutionary differences and trends between primate brains.