Biomedical subjects

Facundo Valverde

Publications and source records attributed to Facundo Valverde.

2 recordsLinked to original sources

PubMed2002

Tangential migration in neocortical development.

During cortical development, different cell populations arise in the basal telencephalon and subsequently migrate tangentially to the neocortex. However, it is not clear whether these cortical cells are generated in the lateral ganglionic eminence (LGE), the medial ganglionic eminence (MGE), or both. In this study, we have generated a three-dimensional reconstruction to study the morphological formation of the two ganglionic eminences and the interganglionic sulcus. As a result, we have demonstrated the importance of the development of these structures for this tangential migration to the neocortex. We have also used the tracers DiI and BDA in multiple experimental paradigms (whole embryo culture, in utero injections, and brain slice cultures) to analyze the routes of cell migration and to demonstrate the roles of both eminences in the development of the cerebral cortex. These results are further strengthened, confirming the importance of the MGE in this migration and demonstrating the early generation of tangential migratory cells in the LGE early in development. Finally, we show that the calcium-binding protein Calretinin is expressed in some of these tangentially migrating cells. Moreover, we describe the spatiotemporal sequence of GABA, Calbindin, and Calretinin expression, showing that these three markers are expressed in the cortical neuroepithelium over several embryonic days, suggesting that the cells migrating tangentially form a heterogeneous population.

Animals↗

PubMed2002

Neuronal changes during development and evolution (an overview).

This overview highlights the presentations made by several authors, with sidelights commentaries on the topics covered in this session. The Neurotropic hypothesis, formulated by Cajal more than one century ago, has been one of the fundamental tenets of modern Neuroscience. Research work is unveiling highly complex molecular mechanisms by means of which neuronal processes grow in the right direction leading to the formation of neural networks. Another interesting topic covered in this session pertains to the remarkably conserved similarity of most parts of the brain between reptiles, birds and mammals. The presence of the neocortex, which occurs in mammals, is discussed on the basis of different migratory behavior during development. The question of neuronal stability throughout the life cycle raises interesting aspects on the generation of new neurons. This is a particularly timely topic because recent evidence, denied by others, has shown the generation of new neocortical neurons in the adult. In another session, it was discussed the evidence showing that pyramidal cells and intrinsic cells of the neocortex have different developmental origins. Finally, several modern analyses show the role of different transcription factors in the formation of brain cortical maps before the arrival of their proper afferent connections.

Afferent Pathways↗