Scientists Put A 'Sixth Sense' For Numbers On Brain Map

One of the most famous scenes in the movie Rain Man unfolds when a waitress drops a box of toothpicks on the floor. Dustin Hoffman's character, Ray, takes a look and says, "82, 82, 82." He quickly sums the numbers, declaring, "Of course, 246 total."

It was almost if Ray had a sense about how many toothpicks were there. That he didn't actually need to count them. Turns out, we all have a bit of this ability — although few of us are as facile as Ray.

Scientists have found a region of the brain that quickly senses quantities. It's a small patch of neurons just above each ear that allows us to say at a glance, "Oh yeah, there are five meatballs on my plate, but there are maybe a hundred strands of spaghetti."

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In seconds, Ray knows there are 246 toothpicks dropped on the floor.

Some scientists think of this ability as a kind of sixth sense, something like a number sense. One reason is that the skill appears to originate in specific parts of the brain much like our sense of touch and sight, a team of scientists said Thursday in the journal Science.

"When we see a small number of items visually, we don't need to count them," says Ben Harvey, of Utrecht University in the Netherlands, who lead the study. "We just know how many there are straight away."

Most people hit their limit at around five items, Harvey says. Then people get less and less accurate about estimating the quantity.

But there's definitely variation among people. "One subject we measured was just beautiful," he says. "His brain responds all the way through the number eight."

The better you are at number sensing, Harvey says, the better you tend to do on standardized mathematical tests. "This part of the brain — and the ones nearby — is active when you do math and solve equations, as well." But it's distinct from the region that recognizes numerical symbols, like a "5" displayed on a computer screen.

Monkeys aren't mathematicians, but previous studies had found neurons in monkeys' brains that light up when the animals see a specific quantity, like three circles on the screen.

A sixth sense? A small patch of neurons on either side of the brain recognizes how many dots are on a screen. As more dots appear, active neurons shift to the right.

Courtesy of Ben Harvey/Utretch University A sixth sense? A small patch of neurons on either side of the brain recognizes how many dots are on a screen. As more dots appear, active neurons shift to the right.

Courtesy of Ben Harvey/Utretch University

So Harvey and his team went hunting for similar neurons in people. The team showed people a series of circles on the screen: one circle, then two circles all the way up to eight circles. They mapped the activity in their brains using a technique called functional magnetic resonance imaging.

Throughout the experiments, a group of about 80,000 neurons — or a clump about the size of a postage stamp — kept lighting up in the fMRI for all eight people they studied. And there was a pattern: Neurons that sensed the smaller numbers were located on one side of the patch while those that responded to larger numbers were on the other side.

It's similar to how the brain organizes other senses, like touch and sight. "There are maps on the brain that represent the surface of the skin — or the surface of the retina," Harvey says. "These all reflect an external organ. We found the first map for a cognitive function."

The brain allocates more computing power for tasks it wants to excel at. "For seeing, there's more neurons that process the center of the field vision, where you have very sharp vision," he says. "For touch, you have huge hands mapped onto the brain, but smaller ones for legs."

The same strategy gets applied to numbers. More neurons are devoted to sensing smaller quantities than larger ones, Harvey and his team found. That's probably why most people can't count 246 toothpicks on the floor in a flash but can quickly do it for five toothpicks.

That brings us back to Ray in Rain Man. Could some people have even more neurons in their number-sense region and wind up with extraordinary capabilities like Ray?

It's too soon to tell, Harvey says.

"The idea is well known because of the movie Rain Man, but few such people exist. And we haven't scanned one," he says. "So we don't really know whether they are doing the same task — that is, determining large numbers quickly and accurately, like we all do for small numbers. We would be very excited to meet one of those savants."

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Sharks go wireless as scientists tag them to track their travels

Meet Mary Lee, a great white shark that's the same weight and nearly the same length as a Buick. And, by the way, you may have been swimming within a few feet of her this past year and not known it.

Since last September, when she received an array of radio, acoustic, and satellite tags, Mary Lee has travelled from Massachusetts to Florida, often hugging the coastline so closely that scientists tracking her called beach authorities in Florida to warn them about her. The 16-foot, 3456-pound shark also headed into open ocean, taking a February vacation off the beaches of Bermuda.

"She was undoubtedly not the only one there. Sharks have probably been doing it for millions of years," said Nick Whitney, a marine biologist with the Mote Marine Laboratories in Sarasota, Florida. "We're learning things that ten years ago we would have never dreamed we could have learned about these species."

OCEARCHMary Lee, a 16-foot 3456-pound great white shark, traversed the East Coast over the past year, at times hugging the shoreline so close as to prompt a warning call from researchers.

Whitney, who spoke from a research vessel off of Cape Cod, Massachusetts, is part of a team that runs OCEARCH, a nonprofit global shark-tracking project that uses four different tagging technologies to create a three-dimensional image of a shark's activities. OCEARCH is hoping to develop successful conservation and management strategies by studying shark habits in more granular detail.

While traditional research has focused on small-scale movements, the data being gathered by OCEARCH offers surprising new information about where sharks go and what they do. That's where the tracking technology is crucial.

A dorsal fin tag attached by OCEARCH uses a satellite to track a shark's position each time it breaks the surface. Other tags include an RFID implant whose ping is picked up whenever the shark passes a special, underwater buoy; an accelerometer, similar to the technology used in an iPhone or Nintendo Wii, that detects up or down movement; and a Pop-off Satellite Archive Tag (PSAT), which acts as a general archive, recording average water depth, temperature and light levels.

"On average, we're collecting 100 data points every second—8.5 million data points per day. It's just phenomenal," Whitney said. "Second by second, we can pick up every tail beat and change in posture."

One of the surprises the tracking data revealed is that white sharks don't always stick to cold water, as previously thought. Some even venture into the Gulf of Mexico during the summer.

In addition to in-depth data, what sets OCEARCH apart from past shark-tracking projects is that anyone—from a child in grade school to a television arm-chair warrior—can see the tracking data at the same time as researchers on the OCEARCH web site.

Each shark's location is represented by an icon on a Google Maps-based TruEarth Viewer. By clicking on the icon, a user can get detailed information such as the species, gender, size, weight, length, as well as where and when the shark was tagged. A user also gets images of the shark as it was being tagged.

By drilling down further, and clicking on the "Where Have I Been" icon, a user can also see a track of where the shark has been since being tagged, in some cases see a detailed trail over the course of a year or more.

OCEARCH expedition leader Chris Fischer calls the methodology "open source" research, since all scientists see the data at the same time; nothing's proprietary. Within a week, OCEARCH also plans to launch a "digital hub" shark tracker platform with a real-time social media interface that allows researchers to post FAQs and videos to the most popular social networks: Facebook, YouTube, Instagram or Twitter, according to OCEARCH spokesman Chris Berger.

OCEARCH will also be launching a Science, Technology, Engineering, and Mathematics (STEM) Education-based curriculum for K-12 students. "We currently have 30 lesson plans for sixth through eighth graders, and will have more for K-12—eventually, even pre-K," Berger said.

Currently, OCEARCH is tracking 47 sharks, some of them bull and mako but mostly great whites off the U.S. East Coast and in the waters off South Africa.

Many of the sharks are given endearing names, such as Princess Fi, Genie, Opera, and Sabrina. Others have handles more befitting ships, such as Poseidon, Redemption, Perseverance, and Courage.

Mary Lee, who was tagged off of Cape Cod, is named after Fischer's mother. "My parents have done so much. I was waiting and waiting for a special shark to name after her and this is truly the most historic and legendary fish I have ever been a part of and it set the tone for Cape Cod," Fischer wrote in an online description of Mary Lee.

Co-Captain Jody Whitworth and master of the Martha's Vinyard OCEARCH team Brett McBride prepare to stabilize a great white shark named Amy. Before taking measurements, blood and securing real-time technology tags, a device is inserted into the shark's mouth to irrigate its gills. (Image: OCEARCH).

To tag the sharks, the OCEARCH team first goes fishing with a hand-held line tipped with special barbless hook, engineered so it won't injure the animal. The team then brings the shark alongside their 126-foot boat, which has an underwater hydraulic lift that can hoist up to 75,000 pounds. That capacity is needed since the team is not only lifting what could be a one- to two-ton shark but also the water around it.

Once the shark is above the water line, from three to eight scientists get to work on it like a NASCAR pit crew, first placing a wet towel across its eyes to calm it and an irrigator in its mouth so it can breath. The crew then rolls the shark on its side to surgically implant the first tracking tag in its belly.

That device, known as an acoustic tag, is about the size of a Sharpie pen. It can remain in the shark for as long as ten years and can be "heard" whenever the animal swims to within a quarter to a half mile of underwater buoys that can pick up a radio frequency specific to marine tagging operations. Throughout the world, marine biologists have anchored such buoys, which can record an acoustic tag's unique ID as well as the day and time.

OCEARCHThe OCEARCH team tags a great white shark off of Cape Cod, Massachusetts.

Once the acoustic tag is in place, the OCEARCH crew rolls the shark back onto its belly and attaches a Smart Position Or Temperature Transmitting (SPOT) device. The SPOT tag is placed high on the shark's dorsal fin because its radio ping can only be received when the shark breaks the surface of the water and a satellite is in position to receive the signal. The longer the fin is out of the water, the more accurate the data. There are six ARGOS global positioning satellites orbiting the earth that can pick up a SPOT tag's ping at any time.

"The ARGOS satellite is only around about every two hours. Then the fin has to stay out of water for minute or two to get a good fix," Whitney said. "It's ridiculous that this works. It's pretty amazing when you look at the map and understand how many fixes we get on these sharks."

The third tag is an accelerometer package, which tracks fine-scale data on the shark's body movement and behavior along with water depth and temperature information. That tag, which is designed to release from the shark after just two days, records more than eight million data points each day, with the information stored to memory. The tag is embedded in a float package that contains a satellite transmitter and a VHF radio tag, which transmits a ping that can be heard over a ten-mile range with a VHF receiver and antenna.

"In this case, the VHF tag allows us to find the needle in the haystack, once the satellite tag tells us where the haystack is," Whitney said.

Although OCEARCH has been using two-day accelerometer tags, the team off Cape Cod is now going for the longest accelerometer track of a shark ever: two weeks of second-by-second behavioral information.

Finally, OCEARCH researchers attach a PSAT archival satellite tag, which records depth, temperature, and light levels (used for geolocation) and stores the data to memory. The tag is programmed to release from the fin anywhere from six months to a year after being attached. It then floats to the surface and processes and summarizes the data for transmission back to researchers via satellite.

"It'd be great if there was one tag to get all the information, but there's not," Berger said.

The researchers have gotten the tagging procedure down to, well, a science. They've perfected the process by performing it on more than 100 sharks—67 of them great whites.

To date, the largest great white the team has captured and tagged is an 18-foot, 5000-pound animal named Apache. Apache currently holds the world record as the largest fish ever caught and released by anyone, Berger said.

For their massive size and ferocious reputation, white sharks actually represent a small minority of shark attacks throughout the world, including the shark attack capital, Florida.

"Florida has more shark incidents than any place in the world, but virtually all of those bites form small sharks—black tips and spinner sharks. In fact, I'm not sure of any confirmed white shark attacks there," Whitney said.

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Eyeing faster chips, scientists measure super-fast electrical switching

Researchers in Silicon Valley have managed to observe electrical switching that is thousands of times faster than transistors used in today’s computer chips. Their work could lead to a better understanding of how transistors work at the atomic level and, in turn, help to enable more powerful computers.

Transistors are semiconductor devices that act as simple on-off electrical switches. The number of transistors in a computer chip has a direct effect on its speed and power, so researchers are continually trying to make their transistors smaller and faster.

In work at the SLAC National Accelerator Laboratory in Menlo Park, California, researchers using an X-ray laser to discovered it takes just one trillionth of a second to switch between on and off states in a sample of magnetite, a type of mineral.

They hit each sample with a pulse of visible light from a laser, which caused the electronic structure of the material to rearrange itself. Immediately afterwards, they hit it with a burst from an ultrabright, ultrashort X-ray laser which revealed that the rearrangement had begun hundredths of quadrillionths of seconds after the initial pulse hit the sample.

The precise time for the switching from a non-conducting (off) state to a conducting (on) state was determined by varying the interval of the X-ray laser pulses.

“This breakthrough research reveals for the first time the ‘speed limit’ for electrical switching in this material,” Roopali Kukreja, a materials science researcher at SLAC and Stanford University who is a lead author of the study, said in a statement.

Despite the research, chips made from magnetite aren’t expected anytime soon. The research required the material to be cooled to minus 190 degrees Celcius, which makes it impractical for widespread commercial use.

Greg Stewart / SLACAn optical laser pulse (red streak from upper right) shatters the ordered electronic structure (blue) in an insulating sample of magnetite, switching the material to electrically conducting (red) in one trillionth of a second.

But, using the research as a base, the team will go on to study more complex materials and applications at room temperature, a SLAC spokesman said. The hope is that increased knowledge of electrical switching in materials like magnetite will help scientists understand the switching inside materials such as silicon, which is used in current chips, or new hybrid materials that might offer improvements on silicon.

The research was published July 28 in Nature Materials. It was carried out with scientists in Germany, the Netherlands, Italy, Switzerland and other facilities in the U.S.

Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service.
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