Proliferative Capacity of Adult Mouse Brain.

Mikhail Semenov

doi:10.3390/ijms22073449

Abstract

We studied cell proliferation in the postnatal mouse brain between the ages of 2 and 30 months and identified four compartments with different densities of proliferating cells. The first identified compartment corresponds to the postnatal pallial neurogenic (PPN) zone in the telencephalon; the second to the subpallial postnatal neurogenic (SPPN) zone in the telencephalon; the third to the white matter bundles in the telencephalon; and the fourth to all brain parts outside of the other three compartments. We estimated that about 3.4 million new cells, including 0.8 million in the subgranular zone (SGZ) in the hippocampus, are produced in the PPN zone. About 21 million new cells, including 10 million in the subependymal zone (SEZ) in the lateral walls of the lateral ventricle and 2.7 million in the rostral migratory stream (RMS), are produced in the SPPN zone. The third and fourth compartments together produced about 31 million new cells. The analysis of cell proliferation in neurogenic zones shows that postnatal neurogenesis is the direct continuation of developmental neurogenesis in the telencephalon and that adult neurogenesis has characteristics of the late developmental process. As a developmental process, adult neurogenesis supports only compensatory regeneration, which is very inefficient.

Highlights

The ganglionic eminences (Figure 10A,B,D) transform into a layer of actively proliferated cells located in the dorsal and medial walls of the CP (Figures 8 and 10C,E)
This layer, the caudate migratory stream (CMS), includes the subependymal zone (SEZ) that corresponds to the CMS part located in the lateral walls of the lateral ventricle
We showed previously that neurogenesis can be detected in all parts of the CMS

Summary

Introduction

The mammalian brain has a very limited capacity for self-repair. For a long time this was attributed to the absence of neurogenesis in the adult mammalian brain [1,2]. In the mid-1960s, the first evidence that neurogenesis could be present in the adult mammalian brain had started to appear [3]. The following fifty years brought many exciting discoveries that unequivocally showed the existence of neurogenesis in the adult mammalian brain [4,5]. Toward the mid-1980s, it was established that adult-born neurons have the electrophysiological properties of real neurons [6,7].

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Conclusion