Joint research led by Yu Toyoshima and Yuichi Iino of the University of Tokyo has demonstrated individual differences in, and successfully extracted commonalities from, the whole-brain activity of roundworms. The researchers also found that computer simulations based on the whole-brain activity of roundworms more accurately reflect real-brain activity when they include so-called “noise,” or probabilistic elements. The findings were published in the journal PLOS Computational Biology.

The roundworm Caenorhabditis elegans is a favorite among neuroscientists because its 302 neurons are completely mapped. This gives a fantastic opportunity to reveal their neural mechanism at a systems level. Thus far, scientists have been making progress in revealing the different states and patterns of each neuron and the assemblies they form. However, how these states and patterns are generated has been a less explored frontier.

First, the team of scientists measured the neural activity of each cell that makes up a primitive brain in the roundworms’ head area. To achieve this, the worms were placed in a microfluidic chip, a tiny device designed for worms to be able to “wiggle” backward and forward while keeping them within the field of view of the objective lens. Then, using a confocal microscope, the scientists filmed how the neurons reacted to changes in salt concentrations.