Archive for the ‘Olfactory bulb’ Category

Neuron of fetal origin in the maternal brainImage by koolkao via Flickr Damage to the human brain, ie. loss of cells due to programmed or non-programmed cell death is presently considered to be an irreversible fate. Many a skilled neurosurgeon can place new neurons or stem cells into damaged areas, but that does little good unless those cells are able to sprout new axons and dendrites that migrate outward – sometimes very long distances – and make the proper synaptic connections and re-establish functional neural networks. Presumably, the instructions that tell a cell where, and how far to go, and whom to synapse with when you get there, are a mix of autonomous and pre-programmed genetic instructions but also environmentally determined (turn left when you see the McDonald’s at the globus pallidus). Kelsch and team, in their open-access paper, “Distinct Mammalian Precursors Are Committed to Generate Neurons with Defined Dendritic Projection Patterns(DOI) show that, for a certain type of neuron at least, the instructions are pre-programmed. The research team found that granule cell precursor cells in a part of the mouse brain called the olfactory bulb, show distinct patterns of where dendritic trees connect with other cells – in either deep layers of the cortex or superficial layers. These cells maintain their layer-specific patterns of dendritic connectivity even after transplantation suggesting that all the instructions needed are contained within the nucleus of the cell. Further understanding of the specific genetic instructions contained therein opens new roadways for the repair of brain damage.

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