Contrary to the widespread opinion about static nature of the mammalian brain, processes of neurogenesis in the adult, mature brain were found to be objective reality. Only some brain areas, such as olfactory bulb and fascia dentata hippocampi, are capable of neurogenesis in the adult organism. At the same time, quite a few stem cell precursors can exist in different parts of the mature brain. J. Emsley has taken part in the investigations demonstrated that new neurons could be added to the mature neocortical neuronal networks. That fact can be connected to the transplantation of neurons derived from nerve cell precursors or via manipulation with endogenous precursors (including induction of limited neurogenesis in long-distant projections of cortical neurons observed in adult mice). Taking into consideration neuron heterogeneity and complexity of links between neurons in the mammalian cerebral cortex, trials aimed at reconstruction of functional neuronal network require detailed understanding of the significance of signals pointed at neuron differentiation, neuron junctions and survival of certain types of neurons. Developmentally regulated transcription factors for definite types of neurons were marked out; those transcription factors for motor and corticotectal neurons, and neurons of the corpus callosum differed one from another. Gene-specific analysis for neuronal subtypes in the cerebral cortex determined existence of a program combining molecular genetic control with precise development of key cortical neuronal projections. Scientists hope that subsequently, it will be able to stimulate neuron differentiation from progenitors in other brain areas, expecting local therapeutic effect, which does not contradict heterogeneity of the source material, for neurodegenerative diseases and brain injuries treatment. Results of those investigations are important for the directed control of neural progenitor (stem cell) differentiation concerning functional restoration of the central nervous system.
Place of employment — Harvard University, USA.
Contacts — Edwards 410 (EDR 410), 50 Blossom Street, Boston MA 02114, USAjemsley@dal.ca .
Publications — Proliferation and expression of progenitor and mature retinal phenotypes in the adult mammalian ciliary body after retinal ganglion cell injury. Nickerson PE, Emsley JG, Myers T, Clarke DB. Invest Ophthalmol Vis Sci. 2007 Nov;48(11):5266–75.Astroglial heterogeneity closely reflects the neuronal-defined anatomy of the adult murine CNS.Emsley JG, Macklis JD. Neuron Glia Biol. 2006 Aug;2(3):175–186.
