Is there a neuron that can order the brain stem to make more new neurons? Probably yes, say a group of Duke Researchers based on experiments that are in their early stages. Tantalizingly enough, the answer to that question may be ‘yes.’
Although for some time now neuroscientists have suspected that the brain can direct the manufacturing of new neurons, they could not pinpoint the source of these directions, explains Chay Kuo, MD Ph.D., an assistant professor of cell biology, neurobiology and paediatrics.
Now the researchers have uncovered a mass of neurons within the sub ventricular zone (SVZ) adjacent to the striatum that may be sending out these signals, an inference reinforced by the fact that these neurons produce choline acetyltransferase (ChAT) an enzyme, required to make the neurotransmitter acetylcholine.
The researchers claim that as part of an as yet undescribed neural circuit the mature ChAT+ neuron population asks the stem cells to step up new neuron production. Although they are yet to find all the parts of the circuit or the code the ChAT+ neurons use, the Duke scientists have established that these neurons are necessary and sufficient to control the production of new neurons from the SVZ niche.
“This is an incredibly exciting discovery. A hidden gateway, a neural circuit capable of directly instructing the stem cells to make more immature neurons,” said Kuo, who is also the George W. Brumley, Jr. M.D. assistant professor of developmental biology and a member of the Duke Institute for Brain Sciences. “The brain vacates prime real estate around the lateral ventricles for the SVZ niche housing these stem cells. Is it some kind of factory taking orders?”
Studies have proved that SVZ cells migrate into neighbouring striatum among stroke-afflicted rodents. Last month a Swedish team made discovered newly made control neurons called interneurons in the human striatum. They reported that interestingly in Huntington’s disease patients, this area seems to lack the new born interneurons.
Said a researcher, “it’s a gorgeous niche where you can observe cell-to-cell interactions.” These latest breakthroughs have made Kuo and his team hopeful that in the future we will be able to engage certain circuits of the brain and engineer a hardware upgrade. “Wouldn’t it be nice if you could upgrade the brain hardware to keep up with the new software?” says Kuo. This will probably lead to a way of combining behavioural therapy and stem cell treatments after a brain injury to undo some of the damage.