The Value of a Virus

So ask your researcher to use a virus to figure out how neurons recruit their neighbors  to help them as neuroplasticity proves.
http://www.brainfacts.org/about-neuroscience/technologies/articles/2013/the-value-of-a-virus/

From the nuisance of the common cold to the debilitating symptoms of AIDS, it’s rare to hear a positive story about a virus. But, as it turns out, with the proper manipulations, viruses can do a lot more than cause disease. In fact, scientists use genetically modified viruses to visualize the connections between cells and treat disease.

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With the right genetic instructions, scientists coax viruses to carry information capable of illuminating the inner workings of the brain and delivering therapy. Lentiviruses, like the one illustrated above, are among the most common viruses used in laboratories.

A.J. Cann

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Scientists use modified viruses to help map the connections between cells. Researchers altered an adeno-associated virus (AAV) to introduce green fluorescent protein (GFP) into Purkinje cells (pictured in green above) in the mouse cerebellum — a region that plays a role in motor control.

Megan S. Keiser and Beverly L. Davidson, University of Iowa

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Leber’s congenital amaurosis (LCA), shown in the above retinal scan, is a disease caused by a gene mutation that leads to total blindness by adulthood. Scientists used modified viruses to deliver a normal version of the gene that is mutated in LCA to patients in a small clinical trial. To date, this approach has helped to improve vision in the small number of patients tested.

National Eye Institute, National Institutes of Health

“Viruses give us an opportunity to manipulate particular cells and regions in the brain — even the whole brain — in unprecedented ways that we couldn’t have done 10 to 15 years ago,” says Beverly Davidson, a neuroscientist at the University of Iowa, who uses modified viruses in her study of inherited neurodegenerative diseases. This technique helps scientists gain important insights into a variety of illnesses, including Parkinson’s disease and some forms of blindness.

Beating Viruses at Their Own Game

Viruses — small germs capable of replicating only in other living organisms — have the cunning ability to invade and deliver genetic material to normal cells. When a cold virus, for example, works its way into a cell in the human body, it hijacks the cell’s command center — also known as the nucleus. Once there, the virus instructs the cell to churn out copy after copy of the virus's genetic information. These genetic instructions tell the cell to make more copies of the virus, which go onto infect other cells. Upon recognizing the infection, the body triggers an immune response to fight off the virus.
By swapping out genes from the virus that are harmful to the host cell with other genes, scientists can take advantage of a virus's ability to move from cell to cell and insert new genetic instructions while reducing its ability to cause a dangerous immune reaction.
Once genetically manipulated, the virus simply serves as “a cargo for the genetic material that we place in them,” Davidson says. With the right genetic instructions, scientists coax viruses to carry information capable of illuminating the inner workings of the brain and delivering therapy. Some of the more popular viruses used by neuroscience researchers include rabies, herpes, lentiviruses, and adeno-associated viruses (AAV).

Viruses Light Up Brain Pathways

To understand how the human brain works, neuroscientists study how individual cells, or neurons, connect to one another. And therein lies a huge scientific challenge. The human brain has at least 100 billion neurons and their connections number in the hundreds of trillions.

Some viruses, including herpes and rabies, spread specifically between connected neurons. By modifying the genomes of these viruses so that the neurons they infect can be identified and their spread can be controlled, scientists can map the connections between neurons as the virus moves from cell to cell. With these maps, scientists can better understand the pathways of neurons associated with specific brain functions and illnesses.

In one study, scientists used a modified version of the rabies virus to trace the connections between mouse nerve cells that produce dopamine — a brain chemical that is needed for learning actions. The scientists found a direct connection between the dopamine-producing neurons in two regions of the brain, including one area that is a popular target for deep brain stimulation (DBS) — a surgical procedure used to alleviate symptoms of Parkinson’s disease. The findings may help researchers to better understand how DBS works.