Lifeboat Foundation

We investigated how environment symmetry shapes the neural processing of direction by recording directionally tuned retrosplenial neurons in male Lister hooded rats exploring multicompartment environments that had different levels of global rotational symmetry. Our hypothesis built on prior observations of twofold symmetry in the directional tuning curves of rats in a globally twofold-symmetric environment. To test whether environment symmetry was the relevant factor shaping the directional responses, here we deployed the same apparatus (two connected rectangular boxes) plus one with fourfold symmetry (a 2 × 2 array of connected square boxes) and one with onefold symmetry (a circular open-field arena). Consistent with our hypothesis we found many neurons with tuning curve symmetries that mirrored these environment symmetries, having twofold, fourfold, or onefold symmetric tuning, respectively. Some cells expressed this pattern only globally (across the whole environment), maintaining singular tuning curves in each subcompartment. However, others also expressed it locally within each subcompartment. Because multidirectionality has not been reported in naive rats in single environmental compartments, this suggests an experience-dependent effect of global environment symmetry on local firing symmetry. An intermingled population of directional neurons were classic head direction cells with globally referenced directional tuning. These cells were electrophysiologically distinct, with narrower tuning curves and a burstier firing pattern. Thus, retrosplenial directional neurons can simultaneously encode overall head direction and local head direction (relative to compartment layout). Furthermore, they can learn about global environment symmetry and express this locally. This may be important for the encoding of environment structure beyond immediate perceptual reach.

SIGNIFICANCE STATEMENT We investigated how environment symmetry shapes the neural code for space by recording directionally tuned neurons from the retrosplenial cortex of rats exploring single-or multicompartment environments having onefold, twofold, or fourfold rotational symmetry. We found that many cells expressed a symmetry in their head direction tuning curves that matched the corresponding global environment symmetry, indicating plasticity of their directional tuning. They were also electrophysiologically distinct from canonical head directional cells. Notably, following exploration of the global space, many multidirectionally tuned neurons encoded global environment symmetry, even in local subcompartments. Our results suggest that multidirectional head direction codes contribute to the cognitive mapping of the complex structure of multicompartmented spaces.

In June 2021, NASA’s Juno spacecraft flew close to Ganymede, Jupiter’s largest moon, observing evidence of magnetic reconnection. A team led by Southwest Research Institute used Juno data to examine the electron and ion particles and magnetic fields as the magnetic field lines of Jupiter and Ganymede merged, snapped and reoriented, heating and accelerating the charged particles in the region.

“Ganymede is the only moon in our solar system with its own magnetic field,” said Juno Principal Investigator Dr. Scott Bolton of SwRI. “The snapping and reconnecting of Ganymede’s magnetic field lines with Jupiter’s creates the magnetospheric fireworks.”

Magnetic reconnection is an explosive physical process that converts stored magnetic energy into kinetic energy and heat. Ganymede’s mini-magnetosphere interacts with Jupiter’s massive magnetosphere, in the magnetopause, the boundary between the two regions.

One of the biggest achievements of quantum physics was recasting our vision of the atom. Out was the early 1900s model of a solar system in miniature, in which electrons looped around a solid nucleus. Instead, quantum physics showed that electrons live a far more interesting life, meandering around the nucleus in clouds that look like tiny balloons. These balloons are known as atomic orbitals, and they come in all sorts of different shapes—perfectly round, two-lobed, clover-leaf-shaped. The number of lobes in the balloon signifies how much the electron spins about the nucleus.

That’s all well and good for individual atoms, but when atoms come together to form something solid—like a chunk of metal, say—the outermost electrons in the atoms can link arms and lose sight of the nucleus from where they came, forming many oversized balloons that span the whole chunk of metal. They stop spinning about their nuclei and flow through the metal to carry electrical currents, shedding the diversity of multi-lobed balloons.

Now, researchers at the Quantum Materials Center (QMC) at the University of Maryland (UMD), in collaboration with theorists at the Condensed Matter Theory Center (CMTC) and Joint Quantum Institute (JQI), have produced the first experimental evidence that one metal—and likely others in its class—have electrons that manage to preserve a more interesting, multi-lobed structure as they move around in a solid. The team experimentally studied the shape of these balloons and found not a uniform surface, but a complex structure. This unusual metal is not only fundamentally interesting, but it could also prove useful for building quantum computers that are resistant to noise.

You need not be a student of Japanese Ukiyo-e woodblock prints to recognize artist Katsushika Hokusai’s Under the Wave Off Kanagawa – or the Great Wave, as it has come to be known.

Like Leonardo da Vinci’s Mona Lisa and Botticelli’s The Birth of Venus, it’s been reproduced on all manner of improbable items and subjected to liberal reimagining – something Sarah Urist Green, describes in the above episode of her series The Art Assignment as “numerous crimes against this image perpetrated across the internet.”

Such repurposing is the ultimate compliment.

Astronomers found a large number of ancient-galaxy candidates from a single James Webb Space Telescope (JWST) image.

Astronomers peered into a James Webb Space Telescope (JWST) image. From this view of the deep Universe, they saw a large number of ancient galaxy candidates.

Depending on how bright C/2022 E3 (ZTF) becomes, it could even be visible to the naked eye.

Scientists recently discovered a green comet that was last visible in the night sky 50,000 years ago — that’s so long ago that the Earth was in the midst of the Ice Age.

Now, a NASA blog post points out the fact that the comet will make its closest approach to the sun on January 12. It will be close enough to Earth that it may be visible to the naked eye.

Continue reading “A green comet will soon be visible from Earth for the first time in 50,000 years” »

Galactic shock is changing Stephan’s Quintet in enigmatic ways, according to ALMA and JWST.

New observations made with the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) allowed researchers to see the complex interactions within the multi-galaxy collision event known as Stephan’s Quintet.

Stephan’s Quintet is a group of five galaxies-NGC 7,317, NGC 7318a, NGC 7318b, NGC 7,319, and NGC 7,320, located about 270 million light-years from Earth in the constellation Pegasus.

An international team led by researchers at the Instituto de Astrofísica de Canarias (IAC), Spain, has found two planets with Earth-like masses in the habitable zone of a red dwarf star, just 16 light years from our own Solar System.

Artist’s impression of two Earth-mass planets orbiting the star GJ 1002. Credit: Alejandro Suárez Mascareño and Inés Bonet (IAC)

“Nature seems bent on showing us that Earth-like planets are very common,” explains Alejandro Suárez Mascareño, an IAC researcher, first author of a study that appears in Astronomy & Astrophysics. “With these two, we now know seven in planetary systems quite near to the Sun.”

A powerful solar flare hit Earth last week, causing a radio blackout over parts of Australia and the South Pacific last week, CNET reported. This is one of the most powerful flares seen since October last year and might be a sign of what is coming next.

A solar flare is an eruption of electromagnetic radiation from the Sun’s surface. According to the European Space Agency, flares occur when energy stored in magnetic fields on the solar surface is suddenly released.