( Mice whose brain cells respond to a fla...)Common algae helps illustrate mammalian brain electrical circuitry

Investigators at Duke University Medical Center and the Howard Hughes Medical Institute have engineered a strain of mice whose olfactory brain cells "fire" when exposed to light. This was accomplished by inserting into the cells a gene naturally present in green algae that "turns on" when exposed to light and enables the algae to swim toward the light.

When the researchers shined light on the areas of the brain involved in smell, they could follow in real time what areas of the brain were reacting and where the signals went by seeing differences in electrical current that indicated the presence of the algae gene.

"This work provides a new method in live animals that will define the experimental approach for studying of mammalian neural circuitry in the coming decade," said Michael Ehlers, M.D., Ph.D., a Duke neurobiologist and Howard Hughes Medical Institute investigator.

The researchers published their findings in the April 19, 2007, issue of the journal Neuron. The research was supported by the National Institutes of Health and the Howard Hughes Medical Institute.

"This mouse model and its future variants mark the first use of genetically produced light activation in the study of the intact mammalian brain, and we believe this advance in nerve circuit mapping will be to neurobiology what microarray technology has been to genomic science -- a fundamental breakthrough," Ehlers said. Microarray technology enables scientists to screen thousands of genes at once to look for clusters of genes that may be involved in disease.

Although there are many approaches to studying how different nerve cells in the brain react to stimuli from the environment, this mouse model is the first to be able to provide real-time mapping of bra
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Source:Duke University Medical Center