Scientists have taken the first images of an unrestricted animal, providing insights into how neurons communicate.
Scientists at Princeton University took brain scans of the worm Caenorhabditis elegans as it moved about freely. This type of worm, also called a nematode, is only one millimeter in length and has only 302 neurons in its nervous system. The findings, published in the journal Proceedings of the National Academy of the Sciences, indicate that some activities can be traced to specific neural pathways.
Researchers found that some specific behaviors in the worms could be traced back to 77 neurons. Andrew Leifer, a co-author of the paper and an associate research scholar at Princeton’s Lewis-Sigler Institute for Integrative Genomics, finds these results exciting due to the wider implications for the in-depth study of neuroscience.
Neuroscience is at the beginning of a transition towards larger-scale recordings of neural activity and towards studying animals under natural conditions. This work helps push the field forward on both fronts.
This study was the first time researchers were able to view the entire brain of a moving animal. Prior studies focused only on small subsections of the brain or on the brains of animals whose movements were restricted.
Researchers used a indicator protein to trace the contact of cells with calcium, which is one of the chemicals the brain uses to communicate. The scientists set up three special cameras to record the movement of the worm and the fluorescence of the calcium, and then recorded these for over four minutes. The video recordings of these movements are below.
While these findings are the first of their kind, the application of this type of activity for humans is years away. The human nervous system is made up of billions of cells, as opposed to the relatively simple nervous system of the nematode. Still, researchers believe that these findings could potentially have wider implications. They are now working to discern the correlation between neural activity and behavior.
