Home Medizin Bildgebungsdaten des gesamten Gehirns liefern Einblicke in die neuronale Aktivität von Spulwürmern

Bildgebungsdaten des gesamten Gehirns liefern Einblicke in die neuronale Aktivität von Spulwürmern

von NFI Redaktion

Researchers under the leadership of Yu Toyoshima and Yuichi Iino from the University of Tokyo have uncovered individual differences in the overall brain activity of roundworms and successfully derived commonalities from them. The scientists also found that computer simulations based on the overall brain activity of roundworms more accurately reflect actual brain activity when they include so-called „noise“ or probabilistic elements. The results were published in the journal PLOS Computational Biology.

The roundworm Caenorhabditis elegans is popular among neuroscientists because its 302 neurons are fully mapped. This provides a fantastic opportunity to uncover its neuronal mechanism at the systems level. While scientists have made progress in elucidating the different states and patterns of each neuron and the arrangements formed by them, how these states and patterns are generated is a less explored area.

Initially, the research team measured the neuronal activity of each cell forming a primitive brain in the head region of the roundworms. To achieve this, the worms were placed in a microfluidic chip, a tiny device that allows worms to „wiggle“ back and forth while remaining in the field of view of the objective lens. The scientists then filmed with a confocal microscope how the neurons responded to changes in salt concentration.

„Although we were able to extract commonly occurring neuronal ‚motifs‘ in individuals, we were surprised to find large individual differences in neuronal activity. Information from sensory neurons is transmitted to ‚command neurons‘ via multiple paths to control behavior. Since the neuronal circuits of C. elegans are assumed to be relatively well conserved among individuals, we expected little variation in these pathways between individuals. But remarkably, we found the opposite.“


Yuichi Iino, University of Tokyo

The data obtained from these „movies“ of roundworm brains was then used to create computer simulations of roundworm brains. The initial simulations, containing only deterministic elements, however, led to decreasing „neuronal“ activity. By adding „noise“ to the models, the team achieved an accurate representation of the overall brain activity of the roundworms. The scientists were not only able to estimate the strength of connectivity between neurons but also show that „noise“ is essential for brain activity. This mathematical model could potentially even be applied to analyze neuronal activity in cases where complete connectome data is not yet available.

With such possibilities, the number of exciting new questions seems endless. But you have to choose a scientist.

„We originally designed this study to investigate the neuronal mechanisms that occur when roundworms are attracted to salt,“ explains Iino. „However, to measure the activity of the entire brain, we had to keep the roundworms in a narrow channel so they couldn’t escape. We would like to improve the microscope to track freely moving roundworms and analyze the activity of the entire brain while they are attracted to salt.“

Source:

Journal Reference:

Toyoshima, Y., et al. (2024). Ensemble dynamics and derivation of information flow from whole-brain imaging data. PLOS Computational Biology. doi.org/10.1371/journal.pcbi.1011848.

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