Nav: Home

Timings and behaviour influence worm's response to force

June 26, 2018

How worms respond to signals such as taps or touches depends on details of the signal, including whether it increases or decreases, and on what the animal is doing at the time, says Andrew Leifer and his team of researchers at Princeton University, US. Their new paper is published in eLife.

Their research on the roundworm Caenorhabditis elegans (C. elegans) finds a new level of sophistication in the mechanosensory circuit - the network of neurons associated with sensing external mechanical cues - in the worms' simple brains.

The results pave the way for future investigations into how the brain processes sensory signals and turns them into actions.

The C. elegans brain has just 302 neurons, compared to the human brain's 100 billion neurons. But the animals are still able to sense and respond to their environment, making them a powerful model for studying how a simple brain interprets information to control behaviour.

"The way C. elegans responds to a tap, touch or vibrations has been well studied, revealing that they usually back up when they encounter such forces," says first author Mochi Liu, a graduate student at Princeton's Lewis-Sigler Institute for Integrative Genomics. "This has led to simple models showing how the worm interprets force signals. However, we need a more precise understanding of how forces lead to actions to see how the brain processes sensory information and guides the resulting behaviour."

To gather these insights, Liu and the team began by studying the worm's response to a plate tap - a stimulus generated by tapping a dish containing the animals. While some of them exhibited the usual 'fast-reverse' response, others continued moving forward but slowed down - an unexpected result. The team then used a technique called optogenetics to activate the worms' mechanosensory neurons, giving the animals the sensation of a force even when none was present, and saw the same behaviours in response to this method.

"When C. elegans explores its natural environment and interacts with other organisms, it likely experiences stimuli at various and random times," explains Liu. "We therefore also investigated the worm's response to random, time-varying optogenetic stimulation and found that its behavioral response was tuned to the timings of the signals we delivered. For example, the worms' responses to signals that increased over time were different to their responses to signals that decreased over time."

Most strikingly, the scientists also discovered that the worms' behaviour at the time of experiencing the stimuli influenced how their brains interpreted the information. "When the animals were in the process of changing direction, the same stimulus that normally caused a significant response now had almost no effect on their behaviour," says Andrew Leifer, Assistant Professor of Physics at the Princeton Neuroscience Institute and the senior author on the paper. "This was exciting because it suggests that even the worm's simple circuit for detecting touch is flexible enough to rapidly alter how it interprets a sensory signal."

Leifer suggests this work lays a foundation for understanding the mechanisms by which simple neural circuits interpret external signals. Further research into the neural circuits of worms and larger organisms is now needed to understand how more complicated brains interpret and respond to the world.
-end-
Reference

The paper 'Temporal processing and context dependency in C. elegans response to mechanosensation' can be freely accessed online at https://doi.org/10.7554/eLife.36419. Contents, including text, figures and data, are free to reuse under a CC BY 4.0 license.

Media contacts

Emily Packer, Senior Press Officer
eLife
e.packer@elifesciences.org
01223 855373

Liz Fuller-Wright
Office of Communications
Princeton University
lizfw@princeton.edu
+1 609-258-5729

About eLife

eLife aims to help scientists accelerate discovery by operating a platform for research communication that encourages and recognises the most responsible behaviours in science. We publish important research in all areas of the life and biomedical sciences, which is selected and evaluated by working scientists and made freely available online without delay. eLife also invests in innovation through open source tool development to accelerate research communication and discovery. Our work is guided by the communities we serve. eLife is supported by the Howard Hughes Medical Institute, the Max Planck Society, the Wellcome Trust and the Knut and Alice Wallenberg Foundation. Learn more at https://elifesciences.org/about.

eLife

Related Neurons Articles:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.
Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.
A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.
Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.
Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.
Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.
The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.
Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.
How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.
A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.
More Neurons News and Neurons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.