Tag Archives: primates

The Primate Cerebral Subplate

subplate-thickness-primatesThe mature primate brain consists of many layers with the outer layer or cerebral cortex forming folds known as sulci and gyri. During embryonic development, the brain is divided into zones with the inner-most ventricular zone where neurons are formed and a series of cytoarchitecturally distinct layers forming plates radiating outward. The subplate is located between the inner ventricular zone and the outer cortical plate hosting the migration of neurons allowing brain expansion. Most embryonic brain research is conducted on non-primate mammals but there are substantial differences in the development of the non-primate  and primate brain.  A very recent study utilized existing primate tissue databases to examine the embryonic development of the subplate zone in non-human and human primates. Duque et al. found during that development of the macaque brain, once the neurons have migrated to the subplate they then are pushed downward by axons derived from the subcortical layer before further compression occurs from further axonal development originating from the cortical layer. The implications of this force acting on the neurons within the subplate suggests that thickness of the subplate differs unevenly throughout the brain potentially due to an increased axonal density. Duque et al. suggest the density of axonal fibers increases with demand for more connectivity between brain regions with those areas possessing a high-demand for greater complexity causing a thicker subplate.

Changes at the cellular-level of the subplate also have implications for the development of the cerebral convolutions such as sulci and gyri. It was recently posed that the folding patterns in the human brain are the result of mechanical forces related to the subplate and outer expansion of the cerebral cortex. Tallinen et al. showed through numeric and physical simulations with the support of MRI that during fetal development the subplate stabilizes while the outer cortical plate continues to expand. The final stages of growth see the cortical layer undergo extensive gyrification to form the folding patterns we see in the adult human brain. Overall, a better understanding of human neurobiology informed through non-human primate neurobiology offers a glimpse into the evolutionary pathways which led to the evolution of modern humans.

Alannah Pearson

Non-human primate microCT dataset

Copes et al 2016A new dataset of non-human primate microCT scans is now available. The original specimens (59 species) belong to the Museum of Comparative Zoology at Harvard University. The dataset includes 431 skulls of adults and juveniles (and also some postcranial elements) with resolutions between 18 and 125 microns, depending on the size of the specimen. The scans can be freely downloaded, under registration, from the MorphoSource website, which is an open-access archive of 3D data. From the MorphoSource front page you can easily browse by Institutions, and access the specimens. In addition, the authors have also provided a dataset of landmark configurations digitized from the skull sample, available from Dryad Digital Repository.

Sofia Pedro