How The Brain Builds Panoramic Memory

When asked to visualize your childhood home, you can probably picture not only the house you lived in, but also the buildings next door and across the street. MIT neuroscientists have now identified two brain regions that are involved in creating these panoramic memories.


These brain regions help us to merge fleeting views of our surroundings into a seamless, 360-degree panorama, the researchers say.

“Our understanding of our environment is largely shaped by our memory for what’s currently out of sight,” says Caroline Robertson, a postdoc at MIT’s McGovern Institute for Brain Research and a junior fellow of the Harvard Society of Fellows. “What we were looking for are hubs in the brain where your memories for the panoramic environment are integrated with your current field of view.”

Robertson is the lead author of the study, which appears in the Sept. 8 issue of the journal Current Biology. Nancy Kanwisher, the Walter A. Rosenblith Professor of Brain and Cognitive Sciences and a member of the McGovern Institute, is the paper’s lead author.

Building memories

As we look at a scene, visual information flows from our retinas into the brain, which has regions that are responsible for processing different elements of what we see, such as faces or objects. The MIT team suspected that areas involved in processing scenes — the occipital place area (OPA), the retrosplenial complex (RSC), and parahippocampal place area (PPA) — might also be involved in generating panoramic memories of a place such as a street corner.

If this were true, when you saw two images of houses that you knew were across the street from each other, they would evoke similar patterns of activity in these specialized brain regions. Two houses from different streets would not induce similar patterns.

“Our hypothesis was that as we begin to build memory of the environment around us, there would be certain regions of the brain where the representation of a single image would start to overlap with representations of other views from the same scene,” Robertson says.

The researchers explored this hypothesis using immersive virtual reality headsets, which allowed them to show people many different panoramic scenes. In this study, the researchers showed participants images from 40 street corners in Boston’s Beacon Hill neighborhood. The images were presented in two ways: Half the time, participants saw a 100-degree stretch of a 360-degree scene, but the other half of the time, they saw two noncontinuous stretches of a 360-degree scene.

After showing participants these panoramic environments, the researchers then showed them 40 pairs of images and asked if they came from the same street corner. Participants were much better able to determine if pairs came from the same corner if they had seen the two scenes linked in the 100-degree image than if they had seen them unlinked.

Brain scans revealed that when participants saw two images that they knew were linked, the response patterns in the RSC and OPA regions were similar. However, this was not the case for image pairs that the participants had not seen as linked. This suggests that the RSC and OPA, but not the PPA, are involved in building panoramic memories of our surroundings, the researchers say.

Priming the brain

In another experiment, the researchers tested whether one image could “prime” the brain to recall an image from the same panoramic scene. To do this, they showed participants a scene and asked them whether it had been on their left or right when they first saw it. Before that, they showed them either another image from the same street corner or an unrelated image. Participants performed much better when primed with the related image.

“After you have seen a series of views of a panoramic environment, you have explicitly linked them in memory to a known place,” Robertson says. “They also evoke overlapping visual representations in certain regions of the brain, which is implicitly guiding your upcoming perceptual experience.”

Phivolcs Warns Of ‘Big’ Mayon Eruption In Coming Days

LEGAZPI CITY, Philippines – The Philippine Institute of Volcanology and Seismology (Phivolcs) has warned of a possible “big” Mayon volcano eruption in the coming days.


“Phreatic explosion may happen anytime but a big explosion is expected in the coming days,” said Philvolcs resident volcanologist Eduardo Laguerta.

Laguerta cited “abnormal activity” similar to what happened prior to the Mayon eruption in 1984.

The 1984 Mayon eruption is classified as a Vulcanian-type eruption which involves relatively small but violent explosions of thick lava producing columns of ash, gas, and occasional pyroclastic flows.

“The massive drying up of wells across Albay, specifically in the municipalities surrounding the volcano, may be attributed to the magma movement activity beneath the restive volcano,” Laguerta added.

He also cited the 3 consecutive earthquakes in August originating from the Sto Domingo fault line, which can affect volcanic activity.

Laguerta said his office asked geodetic engineers from the Phivolcs central office to conduct a ground survey around the volcano following the earthquakes.

“We noted after the survey, Mayon is inflated, magma beneath the volcano is building up. Deep wells are drying up surrounding the volcano and in several towns here – an implication of abnormal activity,” he said.

Magmatic eruption possible

Laguerta said that while magma build-up did not progress past the belly of the volcano during its explosion in 2014, a “magmatic eruption” may happen this time around.

“Today the possibility to continue for magmatic eruption is possible. We cannot discount the possibility of big explosion,” he said.

With these latest findings, Phivolcs raised Mayon to Alert Level 1.

According to a Phivolcs advisory, its monitoring showed the following:
– Increased sulfur dioxide emission from the Mayon crater, or beyond the baseline level of 500 tons per day, even exceeding 1,000 tons per day on some days, since July 2016.
– Increased volcanic earthquake activity, with a total of 146 earthquakes recorded by the Mayon Volcano Observatory seismic network from August 3 to August 6 on the southeast side, 10 kilometers away from the volcano.
– 4 of the 14 monitored water wells located on the southeastern side of Mayon are drying up, while one has completely dried up
Steam activity from the crater has ranged from weak to moderate, and no crater glow – which would indicate magma activity – has been observed. Even so, Phivolcs warned of a phreatic explosion anytime that could lead to a big eruption.

Rocks and steam are spewed out during a phreatic explosion.

Laguerta also reiterated the government’s warning for the public to stay out of the 6-kilometer danger zone, to avoid casualties.

In 1993, 77 farmers were killed, while several foreigners and their Filipino tourist guide were killed in phreatic explosions in 2013.

Cedric Daep, Albay Public Safety and Emergency Management Office (Apsemo) chief, said there are 18,000 people living along the slopes of the volcano.

Mayon has an elevation of 2,462 meters and is about 300 kilometers away from Manila. Its worst eruption was in 1814, which killed 1,200 people.

Hubble Discovers Rare Fossil Relic Of Early Milky Way

A fossilised remnant of the early Milky Way harbouring stars of hugely different ages has been revealed by an international team of astronomers. This stellar system resembles a globular cluster, but is like no other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way and bridges the gap in understanding between our galaxy’s past and its present.


Terzan 5, 19,000 light-years from Earth, has been classified as a globular cluster for the forty-odd years since its detection. Now, an Italian-led team of astronomers have discovered that Terzan 5 is like no other globular cluster known.

The team scoured data from the Advanced Camera for Surveys and the Wide Field Camera 3 on board Hubble, as well as from a suite of other ground-based telescopes [1]. They found compelling evidence that there are two distinct kinds of stars in Terzan 5 which not only differ in the elements they contain, but have an age-gap of roughly 7 billion years [2].

The ages of the two populations indicate that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation. “This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study, from INAF, Italy, and the University of Gröningen, Netherlands.

Its unusual properties make Terzan 5 the ideal candidate for a living fossil from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.

“We think that some remnants of these gaseous clumps could remain relatively undisrupted and keep existing embedded within the galaxy,” explains Francesco Ferraro from the University of Bologna, Italy, and lead author of the study. “Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way.”

While the properties of Terzan 5 are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way. These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

This assumption is strengthened by the original mass of Terzan 5 necessary to create two stellar populations: a mass similar to the huge clumps which are assumed to have formed the bulge during galaxy assembly around 12 billion years ago. Somehow Terzan 5 has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

“Some characteristics of Terzan 5 resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation,” continues Ferraro.

Hence, this discovery paves the way for a better and more complete understanding of galaxy assembly. “Terzan 5 could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” explains Ferraro while commenting on the importance of the discovery. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivaled view into the complicated history of the Milky Way.

Reconciling Dwarf Galaxies With Dark Matter

Dwarf galaxies are enigmas wrapped in riddles. Although they are the smallest galaxies, they represent some of the biggest mysteries about our universe. While many dwarf galaxies surround our own Milky Way, there seem to be far too few of them compared with standard cosmological models, which raises a lot of questions about the nature of dark matter and its role in galaxy formation.


New theoretical modeling work from Andrew Wetzel, who holds a joint fellowship between Carnegie and Caltech, offers the most accurate predictions to date about the dwarf galaxies in the Milky Way’s neighborhood. Wetzel achieved this by running the highest-resolution and most-detailed simulation ever of a galaxy like our Milky Way. His findings, published by The Astrophysical Journal Letters, help to resolve longstanding debates about how these dwarf galaxies formed.

One of the biggest mysteries of dwarf galaxies has to do with dark matter, which is why scientists are so fascinated by them.

“Dwarf galaxies are at the nexus of dark matter science,” Wetzel said.

Dark matter makes up a quarter of our universe. It exerts a gravitational pull, but doesn’t seem to interact with regular matter — like atoms, stars, and us — in any other way. We know it exists because of the gravitational effect it has on stars and gas and dust. This effect is why it is key to understanding galaxy formation. Without dark matter, galaxies could not have formed in our universe as they did. There just isn’t enough gravity to hold them together without it.

The role of dark matter in the formation of dwarf galaxies has remained a mystery. The standard cosmological model has told us that, because of dark matter, there should be many more dwarf galaxies out there, surrounding our own Milky Way, than we have found. Astronomers have developed a number of theories for why we haven’t found more, but none of them could account for both the paucity of dwarf galaxies and their properties, including their mass, size, and density.

As observation techniques have improved, more dwarf galaxies have been spotted orbiting the Milky Way. But still not enough to align with predictions based on standard cosmological models.

So scientists have been honing their simulation techniques in order to bring theoretical modeling predictions and observations into better agreement. In particular, Wetzel and his collaborators worked on carefully modeling the complex physics of stellar evolution, including how supernovae — the fantastic explosions that punctuate the death of massive stars — affect their host galaxy.

With these advances, Wetzel ran the most-detailed simulation of a galaxy like our Milky Way. Excitingly, his model resulted in a population of dwarf galaxies that is similar to what astronomers observe around us.

As Wetzel explained: “By improving how we modeled the physics of stars, this new simulation offered a clear theoretical demonstration that we can, indeed, understand the dwarf galaxies we’ve observed around the Milky Way. Our results thus reconcile our understanding of dark matter’s role in the universe with observations of dwarf galaxies in the Milky Way’s neighborhood.”

Despite having run the highest-resolution simulation to date, Wetzel continues to push forward, and he is in the process of running an even higher-resolution, more-sophisticated simulation that will allow him to model the very faintest dwarf galaxies around the Milky Way.

“This mass range gets interesting, because these ‘ultra-faint’ dwarf galaxies are so faint that we do not yet have a complete observational census of how many exist around the Milky Way. With this next simulation, we can start to predict how many there should be for observers to find,” he added.

The co-authors on Wetzel’s paper are: Philip Hopkins of Caltech, Ji-Hoon Kim of Stanford University, Claude-André Faucher-Giguére of Northwestern University, Dušan Kereš of University of California San Diego, and Eliot Quataert of University of California Berkeley.

Tropical Storm Newton Makes Second Landfall in Mexico, Threatens U.S. With Rain

Hurricane Newton weakened to a tropical storm as it made its second landfall in Mexico early Wednesday, but forecasters warned it would dump dangerous amounts of rain on the U.S. later in the day.


The storm faded after unleashing 90-mph winds and heavy rains on the tourist resorts of Los Cabos on Tuesday.

Hurricane Newton weakened to a tropical storm as it made its second landfall in Mexico early Wednesday, but forecasters warned it would dump dangerous amounts of rain on the U.S. later in the day.

The storm faded after unleashing 90-mph winds and heavy rains on the tourist resorts of Los Cabos on Tuesday.

By 8 a.m. ET, Mexico’s government had discontinued all coastal watches and warnings for the storm, which was located about 55 miles northwest of Hermosillo, Mexico, and about 180 miles south-southwest of Tucson, Arizona.

Newton’s maximum sustained winds were 60 mph, the National Hurricane Center said in its 8 a.m. advisory. It was moving north at 18 mph.

On Tuesday, Newton smashed windows, felled trees and sparked widespread power outages. Tourists huddled in hotels and locals sheltered in their homes as the storm churned over the Baja California peninsula.

Two people died and three were missing after their shrimp boat capsized in rough seas generated by the hurricane in Mexico’s Gulf of California, according to The Associated Press.

Although it packed a punch, Newton did not bring the same level of destruction to Los Cabos as Hurricane Odile, which devastated parts of the luxury resort region in Sept. 2014.

After crossing the Gulf, the storm made its second landfall on mainland Mexico at around 3 a.m. local time (6 a.m. ET) while packing winds of 70 mph, according to the National Hurricane Center.

Rainfall of up to 12 inches was expected to spark “life-threatening flash floods and mudslides,” especially in coastal areas, according to the Weather Channel.

The storm was set to cross the U.S. border into Arizona around nine hours later.

If Newton keeps its tropical-storm strength all the way to Arizona, it will be only the sixth storm to do so on record, according to Weather Channel meteorologist Jim Cantore.

The National Weather Service has issued flash-flood watches across southern Arizona, New Mexico, and far western Texas. It warned the storm would bring “showers capable of producing heavy rain and in turn causing flash flooding,” with some regions getting as much as five inches during the downpour.

Ripples In Fabric Of Space-time? Hundreds Of Undiscovered Black Holes

New research by the University of Surrey published today in the journal Monthly Notices of the Royal Astronomical Society has shone light on a globular cluster of stars that could host several hundred black holes, a phenomenon that until recently was thought impossible.


Globular clusters are spherical collections of stars which orbit around a galactic centre such as our Milky-way galaxy. Using advanced computer simulations, the team at the University of Surrey were able to see the un-see-able by mapping a globular cluster known as NGC 6101, from which the existence of black holes within the system was deduced. These black holes are a few times larger than the Sun, and form in the gravitational collapse of massive stars at the end of their lives. It was previously thought that these black holes would almost all be expelled from their parent cluster due to the effects of supernova explosion, during the death of a star.

“Due to their nature, black holes are impossible to see with a telescope, because no photons can escape,” explained lead author Miklos Peuten of the University of Surrey. “In order to find them we look for their gravitational effect on their surroundings. Using observations and simulations we are able to spot the distinctive clues to their whereabouts and therefore effectively ‘see’ the un-seeable.”

It is only as recently as 2013 that astrophysicists found individual black holes in globular clusters via rare phenomena in which a companion star donates material to the black hole. This work, which was supported by the European Research Council (ERC), has shown that in NGC 6101 there could be several hundred black holes, overturning old theories as to how black holes form.

Co-author Professor Mark Gieles, University of Surrey continued, “Our work is intended to help answer fundamental questions related to dynamics of stars and black holes, and the recently observed gravitational waves. These are emitted when two black holes merge, and if our interpretation is right, the cores of some globular clusters may be where black hole mergers take place.”

The researchers chose to map this particular ancient globular cluster due to its recently found distinctive makeup, which suggested that it could be different to other clusters. Compared to other globular clusters NGC 6101 appears dynamically young in contrast to the ages of the individual stars. Also the cluster appears inflated, with the core being under-populated by observable stars.

Using computer simulation, the team recreated every individual star and black hole in the cluster and their behaviour. Over the whole lifetime of thirteen billion years the simulation demonstrated how NGC 6101 has evolved. It was possible to see the effects of large numbers of black holes on the visible stars, and to reproduce what was observed for NGC6101. From this, the researchers showed that the unexplainable dynamical apparent youth is an effect of the large black hole population.

“This research is exciting as we were able to theoretically observe the spectacle of an entire population of black holes using computer simulations. The results show that globular clusters like NGC 6101, which were always considered boring are in fact the most interesting ones, possibly each harbouring hundreds of black holes. This will help us to find more black holes in other globular clusters in the Universe. ” concluded Peuten.

Earth’s Carbon Points To Planetary Smashup

Research by Rice University Earth scientists suggests that virtually all of Earth’s life-giving carbon could have come from a collision about 4.4 billion years ago between Earth and an embryonic planet similar to Mercury.


In a new study this week in Nature Geoscience, Rice petrologist Rajdeep Dasgupta and colleagues offer a new answer to a long-debated geological question: How did carbon-based life develop on Earth, given that most of the planet’s carbon should have either boiled away in the planet’s earliest days or become locked in Earth’s core?

“The challenge is to explain the origin of the volatile elements like carbon that remain outside the core in the mantle portion of our planet,” said Dasgupta, who co-authored the study with lead author and Rice postdoctoral researcher Yuan Li, Rice research scientist Kyusei Tsuno and Woods Hole Oceanographic Institute colleagues Brian Monteleone and Nobumichi Shimizu.

Dasgupta’s lab specializes in recreating the high-pressure and high-temperature conditions that exist deep inside Earth and other rocky planets. His team squeezes rocks in hydraulic presses that can simulate conditions about 250 miles below Earth’s surface or at the core-mantle boundary of smaller planets like Mercury.

“Even before this paper, we had published several studies that showed that even if carbon did not vaporize into space when the planet was largely molten, it would end up in the metallic core of our planet, because the iron-rich alloys there have a strong affinity for carbon,” Dasgupta said.

Earth’s core, which is mostly iron, makes up about one-third of the planet’s mass. Earth’s silicate mantle accounts for the other two-thirds and extends more than 1,500 miles below Earth’s surface. Earth’s crust and atmosphere are so thin that they account for less than 1 percent of the planet’s mass. The mantle, atmosphere and crust constantly exchange elements, including the volatile elements needed for life.

If Earth’s initial allotment of carbon boiled away into space or got stuck in the core, where did the carbon in the mantle and biosphere come from?

“One popular idea has been that volatile elements like carbon, sulfur, nitrogen and hydrogen were added after Earth’s core finished forming,” said Li, who is now a staff scientist at Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. “Any of those elements that fell to Earth in meteorites and comets more than about 100 million years after the solar system formed could have avoided the intense heat of the magma ocean that covered Earth up to that point.

“The problem with that idea is that while it can account for the abundance of many of these elements, there are no known meteorites that would produce the ratio of volatile elements in the silicate portion of our planet,” Li said.

In late 2013, Dasgupta’s team began thinking about unconventional ways to address the issue of volatiles and core composition, and they decided to conduct experiments to gauge how sulfur or silicon might alter the affinity of iron for carbon. The idea didn’t come from Earth studies, but from some of Earth’s planetary neighbors.

“We thought we definitely needed to break away from the conventional core composition of just iron and nickel and carbon,” Dasgupta recalled. “So we began exploring very sulfur-rich and silicon-rich alloys, in part because the core of Mars is thought to be sulfur-rich and the core of Mercury is thought to be relatively silicon-rich.

“It was a compositional spectrum that seemed relevant, if not for our own planet, then definitely in the scheme of all the terrestrial planetary bodies that we have in our solar system,” he said.

The experiments revealed that carbon could be excluded from the core — and relegated to the silicate mantle — if the iron alloys in the core were rich in either silicon or sulfur.

“The key data revealed how the partitioning of carbon between the metallic and silicate portions of terrestrial planets varies as a function of the variables like temperature, pressure and sulfur or silicon content,” Li said.

The team mapped out the relative concentrations of carbon that would arise under various levels of sulfur and silicon enrichment, and the researchers compared those concentrations to the known volatiles in Earth’s silicate mantle.

“One scenario that explains the carbon-to-sulfur ratio and carbon abundance is that an embryonic planet like Mercury, which had already formed a silicon-rich core, collided with and was absorbed by Earth,” Dasgupta said. “Because it’s a massive body, the dynamics could work in a way that the core of that planet would go directly to the core of our planet, and the carbon-rich mantle would mix with Earth’s mantle.

“In this paper, we focused on carbon and sulfur,” he said. “Much more work will need to be done to reconcile all of the volatile elements, but at least in terms of the carbon-sulfur abundances and the carbon-sulfur ratio, we find this scenario could explain Earth’s present carbon and sulfur budgets.”