Brain Structural Plasticity: From Adult Neurogenesis to Immature Neurons

Abstract

Brain structural plasticity is an extraordinary tool that allows the mature brain to adapt to environmental changes, to learn, to repair itself after lesions or disease, and to slow aging. A long history of neuroscience research led to fascinating discoveries of different types of plasticity, involving changes in the genetically determined structure of nervous tissue, up to the ultimate dream of neuronal replacement: a stem cell-driven "adult neurogenesis" (AN). Yet, this road does not seem a straight one, since mutable dogmas, conflicting results and conflicting interpretations continue to warm the field. As a result, after more than 10,000 papers published on AN, we still do not know its time course, rate or features with respect to other kinds of structural plasticity in our brain. The solution does not appear to be behind the next curve, as differences among mammals reveal a very complex landscape that cannot be easily understood from rodents models alone. By considering evolutionary aspects, some pitfalls in the interpretation of cell markers, and a novel population of undifferentiated cells that are not newly generated [immature neurons (INs)], we address some conflicting results and controversies in order to find the right road forward. We suggest that considering plasticity in a comparative framework might help assemble the evolutionary, anatomical and functional pieces of a very complex biological process with extraordinary translational potential.

Impaired olfactory neurogenesis affects the performance of olfactory-guided behavior in aged female opossums

“…Newborn neurons in both layers are later incorporated into local circuits and can be involved in analysis of olfactory information 34 , 35 . For many years, the role of adult neurogenesis is studied incessantly, and its contribution to plasticity of the brain is still reported 36 . Integration of newborn neurons into the OB circuits is required for olfactory learning 37 , 38 .…”

Steps towards standardized quantification of adult neurogenesis

“…Short PMI and the use of 4% PFA are considered optimal for labile antigens such as PSA-NCAM and DCX 23 , 28 . However, questions have been raised whether DCX is expressed by cell types other than immature neurons 21 , 29 , may be re-expressed in de-differentiating mature neurons 30 , or represent developmentally generated immature neurons 31 . Novel approaches 32 may be needed to resolve the issue of adult human neurogenesis.…”

Rosehip Neuron - A Review

“…It also has an interaction with local alpha and beta. Ciliary genes are required for the hypothalamic accurate neuron development (Krishna and Babu, 2016;Pascoal, 2019;Rosa, 2020). It is found that the presynaptic zone is essential for axonal transport.…”