What: Developmental divergences that promoted the evolutionary origin of the neocortex
Where: BCBL auditorium
Who: Fernando García-Moreno, PhD, Ikerbasque Research Fellow. Achucarro Basque Center for Neuroscience, Bizkaia, Spain
When: 12 PM
The evolutionary process is intimately linked to the embryonic development. In the brain, changes in the developing program ruling the formation of the brain produced the anatomical and functional divergences present across vertebrate taxa. As a major divergence, the neocortex governs the mammalian brain with its unique six-layered structure. There is no similar structure in other species, which brings the question as to what singular evolutionary mechanisms enabled neocortical origin.
In this talk I will present the latest results of our group in the search of those singular events by comparing the early developing brain of mouse and chick. First, I will focus on the differential contribution of external glutamatergic populations to the development of the dorsal pallium, the embryonic structure that generates the neocortex. The novel arrival of these migratory neurons could have fostered a developmental change that was translated into the evolutionary pathway of ancient mammals.
And second, I will present the neurogenic timing for the generation of sensory circuits. The chronological order in which the different neurons of the cortical circuit are born should be preserved in any cortical homologue of non-mammalian species. However, the neurons participating in the sensory circuit of the avian dorsal ventricular ridge were not generated in an equivalent order to that of the mammalian cortical canonical circuit. It suggests both circuits are not homologous, and their functional correlation could be an unexpected product of evolutionary convergence.