Nature Knows and Psionic Success

Research Similar to the tale of the boiling frog, flies more likely to react to rapid heating

We’ve all heard it: Put a frog in boiling water, and it will jump out. But put the same frog in lukewarm water and heat it gradually, and you’ll cook the frog. Often used as a metaphor for the unhurried and stubborn response many have to a slowly rising threat, the mechanisms underlying the urban myth have become a subject of scientific fascination.

This parable seems to have inspired new Northwestern University research, which identified a brain pathway responsible for rapid-threat detection.

“Animals are more likely to react to rapid rather than slow environmental change,” said lead author Marco Gallio , associate professor of neurobiology in Northwestern’s Weinberg College of Arts and Sciences . “In the present study, we identify a brain circuit in fruit flies that selectively responds to rapid thermal change, priming behavior for escape.”

The findings were published last week in the journal Nature Communications .

Gallio generally uses fruit flies to understand sensory circuits and the ways they create perceptions of the physical world. Using the fly as a model, the lab studies basic decision-making principles in an animal that has a fraction of the number of neurons (100,000) than humans have (roughly 100 billion). As a well-studied model organism for biological research, flies also are useful subjects because of the pre-existing tools to study fly neurons and behavior.

“There are often two types of responses to external stimuli in the brain: Some neurons respond to a stimulus like light or temperature with very persistent activity,” Gallio said. “Other neurons fire just at the beginning, like when a light turns on, and then their activity is gone. We’ve always wondered what the significance of these short-lived responses is.”

In visual stimuli, brains are wired to notice a large contrast between light and dark. Gallio said that the response intuitively also makes sense for the sense of touch: You don’t think about pressure when your hand is resting on a surface. Run your hand over something new, however, and you will detect subtle changes in texture. Gallio’s team wanted to see if the same was true for the sense of temperature.

To explore how flies respond to rapid change, the team used a high-resolution camera to observe flies navigating different temperature environments. When flies encounter a rapid heat front, they always produce a U-turn away from it.

The lab found flies always responded in cases of rapid temperature change, but not for slow change.

The team also identified a circuit in the fly brain that responds only to rapid temperature change (more than 0.2 degrees Celsius per second). Much like light-ON cells of the visual system, these neurons fired at the beginning of rapid heating and then went quiet.

“Our hypothesis was that these heat-ON responses may indeed correlate with the rate of temperature change,” said Jenna Jouandet, the study’s first author and a PhD student in the Gallio Lab. “And therefore, may allow flies to anticipate dangerous thermal conditions and prepare to escape.”

Indeed, when the researchers experimentally inactivated those neurons, flies escaped less promptly. William Kath To better understand how the activity of these neurons may be important for the behavior of the fly, the researchers collaborated with William Kath , applied math professor at Northwestern and deputy director of the new National Institute for Theory and Mathematics in Biology . Applied math PhD student Richard Suhendra built a small computer model with two antennae and two wheels to demonstrate how adding a neuron that anticipates dangerous heat could improve the flexibility of the vehicle response.

<< Play with the model through a simple game on the Gallio Lab webpage .>>

“The neurons that we initially discovered take input from the thermosensory neurons on the antennae and carry information to the higher brain,” Gallio said. “Flies are a great model to map brain circuits in that we were able to reconstruct the full circuit from sensory neurons all the way down to the centers that produce movement.”

Gallio explained that rapid changes are nearly always dangerous for a small fly.

“If the temperature is changing by half a degree per second — which is not that much — within 30 or 40 seconds, that fly could be dead,” Gallio said. “This system is an alarm bell that rings to prime an animal’s behavior for escape. We see the fly escape.”

Gallio hypothesizes that the results are broadly generalizable, especially because he sees it play out in humans, whether someone is entering a room that’s a different temperature or getting into a hot shower. He said these neurons seem to be able to sense something others do not — they seem to be able to anticipate the future. Recent Articles

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Graduate student Emre Caglayan (left) and lead scientist Genevieve Konopka stand in their lab at the Pickens Biomedical Building on the campus of UT Southwestern, Tuesday, Oct. 17, 2023, in Dallas. (ElÃas Valverde II/The Dallas Morning News/TNS) ElÃas Valverde II

The human brain is three times bigger than a chimp’s and more spherical than a Neanderthal’s. Within a maze of bumps and grooves, neurons converse in distinct patterns that give humans unique cognitive abilities.

Scientists haven’t fully deciphered those patterns. But researchers at UT Southwestern Medical Center are determined to solve the molecular mystery of what makes us human.

In a study published in the journal Nature, they compared brain cell types and activities among humans, chimpanzees and rhesus monkeys. Human brains had more of a kind of cell that may help them adapt based on new experience and heal from injury. Certain human neurons also had more of a gene that affects language development.

Genevieve Konopka, whose lab ran the study, has long investigated the molecular mechanisms that lead to brain disease. Understanding the human brain’s inner workings, she said, may help researchers develop therapies to treat conditions like Alzheimer’s and schizophrenia.

The brain’s support crew

Our brains set us apart from other primates. Humans communicate in languages that chimps can’t speak and devise systems of government and religion that don’t exist in the animal kingdom.

Though scientists have compared the cell types and genes in the brains of humans and other primates, they still lack a complete knowledge of how the human brain came to be over millions of years of evolution.

Konopka’s inquiry into brain evolution stemmed from her study of brain disease. In 2019, she compared brain tissue in people with and without schizophrenia and found differences in cells called oligodendrocytes. These cells act like the brain’s support crew, producing insulation that wraps around neurons and helps them send signals faster.

Konopka also saw a difference in oligodendrocytes between human and chimp brains. She realized this support crew could play an important role in both brain disease and human brain evolution.

Konopka wasn’t able to pursue her research further because of technological limits. But in recent years brain studies got a boost from single-cell technology, which allows scientists to capture each cell in a piece of brain tissue and examine the activity of different genes.

Using this technology, Konopka focused on a part of the brain located in what’s called the posterior cingulate cortex. This part is implicated in schizophrenia and is associated with the way we think about ourselves. Konopka said her lab is the first to apply single-cell technology to this region of the brain.

Her lab compared oligodendrocyte amounts and gene activity in human, chimp and rhesus monkey brain tissue. In another experiment, they compared human DNA with genetic information from two ancient human populations: Neanderthals and Denisovans.

Waiting in the wings

Konopka thought her lab would find more oligodendrocytes in human brain tissue compared to that of chimps and rhesus monkeys.

Instead, she found a human-specific increase and gene activity changes in pre-oligodendrocytes: brain cells that haven’t yet evolved to perform their mature functions.

At first, Konopka thought it was a mistake. But after confirming the result, she said, it began to make sense. More pre-oligodendrocytes may help the human brain adapt in response to change or injury, she explained. Having more of these cells may allow us to continue learning into adulthood.

Her lab also found that a gene called FOXP2, which is associated with language development in humans, had higher expression in two types of human neurons. Konopka said the human-specific increase could contribute to the language of human thoughts.

The lab also identified hundreds of genes that may function differently in humans, Neanderthals and Denisovans. These differences shed light on how the human brain evolved over the last 300,000 to 500,000 years, Konopka said.

Konopka’s research adds to the field by not only investigating which genes exist in different brain cells, but also how active they are, according to Doug Broadfield, an associate professor of cell biology at the University of Miami Miller School of Medicine.

“What’s new about this study is that it’s … created a new field of brain evolution,” said Broadfield, who was not involved with the research, “where instead of focusing on the structure of the brain, now we can look at the genetic activity of the brain.”

Konopka hopes to next use single-cell technology to examine brain tissue from people with brain disorders, including schizophrenia.

“We just wanted to set the table, if you will, for future studies looking at brain disease,” she said.

Adithi Ramakrishnan is a science reporting fellow at The Dallas Morning News. Her fellowship is supported by the University of Texas at Dallas. The News makes all editorial decisions.

Read more at www.meadvilletribune.com

Credit: Unsplash/CC0 Public Domain In recent years, the scientific community has seen a push for more findable, accessible, interoperable, and reusable (FAIR) neurophysiology data sharing. While certain measures have been put in place by institutions such as the National Institute of Health (NIH) to promote more FAIR data sharing, some researchers remain hesitant and unwilling to share their data beyond minimum requirements due to multiple disincentives.

In a new Neuron article , a team of researchers, led by co-authors Dr. Vasiliki Rahimzadeh, assistant professor at the Center for Medical Ethics and Health Policy at Baylor College of Medicine, and Dr. Kathryn Maxson Jones, assistant professor of history of technology at Purdue University and formerly a Senior Research Assistant in the Center for Medical Ethics and Health Policy at Baylor during the time of the study, profile three successful instances of data sharing from the NIH BRAIN Initiative Research Opportunities in Humans (ROH) Consortium to highlight the benefits of FAIR data sharing.

“This group is focused on how to maximize the scientific utility of human neuronal data through broad and secure data sharing,” explains Rahimzadeh. “While there has been a lot of attention paid to scientific benefits of data sharing, such as researchers being able to learn from others and expand their own work, far less has been paid to the professional and other social benefits . These value propositions are important for incentivizing researchers to share data more often beyond what is required as a condition of their funding.”

The paper showcases examples of successful data sharing from research groups at the University of Pennsylvania, Cedars-Sinai Medical Center, and Harvard Medical School and Massachusetts General Hospital involving intracranial electrophysiology data from patients. When shared, the data in question was de-identified to protect patient privacy, reformatted into standardized file types and uploaded to institutional or NIH archival databases, where it has been and is being reused for new research, education, training and tool development opportunities.

Rahimzadeh said that by sharing data, the research groups discussed in the paper were able to not only open new doors for collaboration with other groups, but to also support replicability studies that overall enhance scientific rigor.

“The benefits to users include expanding both the diversity and volume of datasets available for research and being able to combine multiple datasets together to find new associations or conduct subgroup analyses that previously might have been infeasible,” she said. “For producers of data, there are benefits of supporting new scientific collaborations and contributing to professional development of trainees who will continue a culture of data sharing.”

Rahimzadeh added that by sharing their data, investigators increase the visibility of their labs, reduce redundancies in similar research studies and benefit from others identifying errors in code or analysis that might otherwise have remained undetected.

“Many pressing research questions about the brain and nervous systems today require analyses of data that are more voluminous and multi-faceted than any single laboratory can reasonably be expected to produce. This makes sharing data all the more important. Additionally, sharing data has had tangible benefits in other fields of life science, such as genomics,” said Dr. Maxson Jones, the co-lead author on the paper, who is now at Purdue University. “Our paper shows that investing in the labor of sharing data in standardized formats comes with its own payoffs.”

Other authors contributing to the paper include Mary A. Majumder, Michael J. Kahana, Ueli Rutishauser, Jie Zheng, Angelique C. Paulk, Sydney S. Cash, Ziv M. Williams, Michael S. Beauchamp, Jennifer L. Collinger, Nader Pouratian, Amy L. McGuire and Sameer A. Sheth. The authors are affiliated with Baylor College of Medicine, Purdue University, the University of Pennsylvania, Cedars-Sinai Medical Center, Boston Children’s Hospital, Massachusetts General Hospital, the University of Pittsburgh and U.T. Southwestern Medical Center.

Provided by Baylor College of Medicine

Read more at medicalxpress.com