"Sculpted light" will allow researchers to map out a worm's central nervous system like never before.
The most common process for studying the nervous system is called light microscopy, but it has serious limitations. The technique forced scientists to choose between spatial or temporal accuracy, a Universitat Wien press release reported.
Studying the nervous system is important in the quest to understand how it "processes sensory input and generates behavior." To accomplish this, scientists have been attempting to map out the nervous system of a small transparent worm called nematode C. elegans, which has only 302 neurons connected by 8,000 synapses.
"Previously, we would have to scan the focused light by the microscope in all three dimensions," quantum physicist Robert Prevedel, said. "That takes far too long to record the activity of all neurons at the same time. The trick we invented tinkers with the light waves in a way that allows us to generate "discs" of light in the sample.
"Therefore, we only have to scan in one dimension to get the information we need. We end up with three-dimensional videos that show the simultaneous activities of a large number of neurons and how they change over time."
Establishing a "functional map" of the worm's nervous system was nearly impossible with light microscopy, this new techniques allows them to record about 70 percent of the worm's nerve cells with high spatial and temporal resolution.
The technique also employs fluorescent proteins, which "light up when they bind to calcium, thus signaling cell activity.
"The neurons in a worm's head are so densely packed that we could not distinguish them on our first images", said neurobiologist Tina Schrödel, co-first author of the study. "Our solution was to insert the calcium sensor into the nuclei rather than the entire cells, thereby sharpening the image so we could identify single neurons." Tina Schrödel, a Doctoral Student in the lab of the IMP Group Leader Manuel Zimmer, said.
The new nervous-system-mapping process will allow for new studies that would have never been possible before. One question researchers hope to answer with this new found technique is how the brain "brain processes sensory information to plan specific movements and then executes them." Finding the answer to this question would require the study of "freely moving animals."
