Lizard Games - Jellyfish Sleep - Astrocyte Stabilization - Free Will Debate

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Jan 7, 2026, 6:36:16 AM (7 days ago) Jan 7

https://www.nytimes.com/2026/01/01/science/this-diminutive-reptile-plays-rock-paper-scissors.html

This Diminutive Reptile Plays Rock-Paper-Scissors

By Carl Zimmer

If you live in the United States, chances are you’re familiar with the game rock-paper-scissors. You put out your hand in one of three gestures: clenching it in a fist (rock), holding it out flat (paper) or holding up two fingers in a “V” (scissors). Rock beats scissors, scissors beat paper and paper beats rock.

Americans by no means have a monopoly on the game. People play it around the world in many variations, and under many names. In Japan, where the game has existed for thousands of years, it’s known as janken. In Indonesia, it’s known as earwig-man-elephant: The elephant kills the man, the man kills the earwig and the earwig crawls up through the elephant’s trunk and eats its brain.

The game is so common that it exists beyond our own species. Over millions of years, animals have evolved their own version of rock-paper-scissors. For them, winning the game means passing down their genes to future generations. A study published on Thursday in the journal Science reveals the hidden biology that makes the game possible — and shows how it may be an important source of nature’s diversity.

The first clues that nature also played rock-paper-scissors emerged three decades ago in the dry hills outside Merced, Calif. Barry Sinervo, a biologist then at Indiana University, studied the common side-blotched lizard there. He would mark the lizards — named for the dark blue or black spot on their side, just behind the front leg — release them into the tall grass and catch the survivors to check up on them in later years.

Dr. Sinervo, who later joined the faculty at the University of California, Santa Cruz, and who died in 2021, grew fascinated by the strange mating habits of the lizards. At the start of every breeding season, the males developed one of three colors on their throats: blue, orange or yellow. And depending on their color, the males behaved differently.

https://www.science.org/content/article/jellyfish-sleep-lot-us-and-same-reasons

Jellyfish sleep a lot like us—and for the same reasons

By Jack Tamisiea

You don’t need a brain to benefit from a good night of sleep. Despite lacking a central nervous system, jellyfish and sea anemones have sleep patterns remarkably similar to those of humans, researchers report today in Nature Communications.

The work supports the idea that sleep arose early in animal evolution to help the first neurons repair themselves, says Cheryl Van Buskirk, a geneticist at California State University, Northridge who was not involved with the research. “This study is another nail in the coffin of the idea that sleep evolved to manage complex, powerful brains.”

In nature, sleep is risky: Snoozing organisms are vulnerable to predators. Yet species across the animal kingdom spend multiple hours a day dozing off—even ancient groups including cnidarians, which include jellyfish, anemones, and corals—all among the earliest animals to develop neurons. Researchers have recorded sleeplike behavior in upside-down jellyfish in the genus Cassiopea and small freshwater relatives of jellyfish known as hydra.

To learn more about why these simple animals sleep, researchers in Israel studied the starlet sea anemone (Nematostella vectensis) and an upside-down jellyfish (Cassiopea andromeda). Both species reside along the bottoms of shallow lagoons with their tentacles hovering in the water to snag prey.

In the lab, the team housed several jellyfish in an aquarium and exposed them to 12 hours of light and 12 hours of darkness over multiple days. They used infrared cameras to monitor how often the critters pulsed their umbrellalike bells, a sign of wakefulness.

https://www.thetransmitter.org/astrocytes/astrocytes-stabilize-circuits-in-adult-mouse-brain/

Astrocytes stabilize circuits in adult mouse brain

By Holly Barker

In early life, astrocytes help to mold neural pathways in response to the environment. In adulthood, however, those cells curb plasticity by secreting a protein that stabilizes circuits, according to a mouse study published last month in Nature.

“It’s a new and unique take on the field,” says Ciaran Murphy-Royal, assistant professor of neuroscience at Montreal University, who was not involved in the study. Most research focuses on how glial cells drive plasticity but “not how they apply the brakes,” he says.

Astrocytes promote synaptic remodeling during the development of sensory circuits by secreting factors and exerting physical control—in humans, a single astrocyte can clamp onto 2 million synapses, previous studies suggest. But the glial cells are also responsible for shutting down critical periods for vision and motor circuits in mice and fruit flies, respectively.

It has been unclear whether this loss of plasticity can be reversed. Some evidence hints that modifying the neuronal environment—through matrix degradation or transplantation of young neurons—can rekindle flexibility in adult brains.

The new findings confirm that in adulthood, plasticity is only dormant, rather than lost entirely, says Nicola Allen, professor of molecular neurobiology at the Salk Institute for Biological Studies and an investigator on the new paper. “Neurons don’t lose an intrinsic ability to remodel, but that process is controlled by secreted factors in the environment,” she says.

Specifically, astrocytes orchestrate that dormancy by releasing CCN1, a protein that stabilizes circuits by prompting the maturation of inhibitory neurons and glial cells, Allen’s team found. The findings suggest that astrocytes have an active role in stabilizing adult brain circuits.

https://bigthinkmedia.substack.com/p/3-philosophical-debates-from-the

3 philosophical debates from the 20th century that neuroscience is reshaping

By Rachel Barr

Philosophers and scientists have always kept close company. Look back far enough, and it’s hard to tell where one ends and the other begins.

Before we had instruments to measure reality, we had to reason our way into it, but that intellectual lineage is what eventually gave us the scientific method. As technology advanced and the scope for observation expanded, specializations splintered off from philosophy to reconstitute as the sciences.

Astronomy cleared the sky of deities and showed us a universe governed by gravity, not gods. Geography mapped a not-so-flat Earth, then geology dated it, stratifying earthly time in isotopes and sedimentary layers. Physics folded time into space, and with it, reimagined us not as beings apart from nature, but as a continuation of its energy and mass. We are not, as Pink Floyd suggested, “lost souls swimming in a fishbowl.” We are matter, muddling our way through life in relativistic motion.

Now, in the 21st century, science is tracing a map through the other great unknown: the mind.

Advances in biophotonics and neuroimaging have brought us closer than ever to a material picture of the mind, but the questions we’re now brushing up against aren’t melting away under empirical gaze. Instead, neuroscience has wandered back to philosophy’s front door, testing the limits of its most durable questions.
1. Free will

In the early 19th century, French physicist Pierre-Simon Laplace imagined the Universe as clockwork, each gear turning in obedience to natural law. He conceived of a demon who, knowing the position and momentum of every particle, could predict the future with perfect accuracy. This thought experiment crystallizes classical determinism: a world where there is no freedom, only inevitability.