UK researchers have found the 12 neurons in a fly brain responsible for creating negative memories.

It’s not enough that we swat flies or lure them to get stuck on glued paper, now we are also writing false memories into their brains. A team of neuroscientists at the University of Oxford have discovered a way to trigger behavior in flies by selectively modifying neurons in their brain and stimulating them with a laser in order to simulate a learning experience. As published in the science journal Cell, flies were made to prefer one smell over another even though they had no real world experience associated with either smell. The experiment has important implications for the eventual development of a technology to create false human memories. We could one day “learn” by having experiences directly inputed into our brains.

Our brains are massive systems of interlocking neurons. In the organization of connections between cells are encoded all the memories of our lifetime. The possibility exists that if we can control these connections, and/or the behavior of the neurons, we could alter our memories; erasing some and creating others. While the brains of flies and humans have vast differences in scale, the structures in one often have an analogous partner in the other. If neuroscientists are able to control the memories of flies, the techniques used could conceivably be adapted into mammals and even humans. Like the fly, we could be made to prefer one stimuli over another based on neuron manipulation, not real world experience.

Gero Miesenbock, leader of the Oxford project, and his team were looking for the cells in the fly brain that are linked to negative associative learning. This learning is how flies (and other animals) link an experience with an undesired outcome. For example, if “bad memories” of being swatted by a human hand are associated with the smell of perfume, the fly may start to avoid perfume. The associative learning neurons produce dopamine as a means of communicating with neighboring cells. Miesenbock modified the neurons of flies by adding a receptor for the chemical ATP (adenosine triphosphate). If ATP showed up around a neuron, it would be stimulated and release dopamine (triggering a “memory”).

There is normally no ATP in the fly brain, but the Oxford team placed some there using tiny light-sensitive molecular cages. Hit the cages with a laser, and the ATP is released, the cells are triggered, releasing dopamine and forming a memory in the fly brain. It sounds complicated but we can make some broad generalizations and summarize: When the laser hits the portion of the fly brain responsible for negative associative learning, it thinks: “Whatever else I’m experiencing now is bad. Very bad, and I don’t like it.”

So what did the UK team want the flies to associate as a bad memory? Smells. Miesenbock and his team already have extensive experience with fly antennae neurons (they published a paper on it) and could test flies readily for smell preference. They exposed flies to two smells, one with the “bad memory laser”, one without. The flies were then allowed to crawl in a small chamber until they came across the two odors, one on each side. Most flies wouldn’t prefer one smell over the other. But those flies who had the correct neurons stimulated by the laser would have a “bad memory” associated with it.

As expected, some flies tended to avoid the “bad memory” smell and move towards the other, even though there was no real-world experience associated with the “bad” smell. The flies had artificially gained a “bad memory” and were acting as if it were real. By tracking which flies behaved accordingly, Miesenbock and his team identified the 12 neurons in a fly brain that are responsible for associative learning. Stimulate those 12 cells, and a fly will likely avoid whatever it is experiencing at the moment.
This stuff is scary and amazingly cool. Just 12 neurons shape the behavior of the entire insect. Imagine the possibilities with humans. By manipulating just a tiny portion of the brain, we could make anything have a negative memory associated with it. The alarmist in me warns that this type of technology could be abused to control people. It could also be used to quit smoking, or eliminate other bad habits. Eventually, this sort of research will hopefully lead to the next step in understanding memories, implanting skills through direct neuron stimulation. Perhaps one day we could have all the experience of a PhD without spending a day in school. For now this is still science fiction, but thanks to flies it has taken one step closer to reality.

[photo credit: Veronica C Burgess (CC)]

The little white nub under the plane fires truck-killing lasers.

For those of us living in fear of a deadly truck uprising, Maximum Overdrive must have scared someone, we can finally rest easy knowing that Boeing [NYSE: BA] recently used a laser attached to a C130H aircraft to kill a pickup. Melting the hood of the truck was a significant step for the Advanced Tactical Laser (ATL), proving it could defeat ground based targets with high precision. The test took place on August 30th at White Sands Missile Range in New Mexico. Military lasers, besides looking really cool for science fiction junkies, also demonstrate that the rapid development of technology could have repercussions in international power politics. Check out the short but sweet video Boeing just released after the break.

While it seems inefficient at this stage, putting a hole in a truck with a laser is just a precursor to a different kind of warfare. We’ve discussed how advancements in robotic weaponry and drones are changing war, and a similar level of change may come from ultra-precise mid to long range weapons. An identified target could be hit from flight without the target being aware of the danger and with little to no collateral damage. Considering the recent record of conventional ordinance, that precision could mean sparing the lives of hundreds of thousands of innocent civilians.

The ATL is a chemical oxygen iodine laser (COIL) which produces hundreds of kilowatts of destructive power in the infrared. That means you, I, and the truck can’t see what’s hitting it. As impressive as that may be, you’re not going to have lasers in the hands of soldiers anytime soon. They take a lot of energy to run (the ATL reportedly consumes megawatts), are bulky (the ATL weighs 5,000+ kg) and aren’t known for being easy to operate. The ATL has a special beam control system in order to acquire targets and guide the laser to where it should strike.

In a critical light, the recent test shows how the US can spend millions of dollars just to disable a truck. I do the same thing unintentionally all the time for free. Still, according to the press release, Boeing is very happy with the ATL. The bottom line, they say, is that it works. As long as progress is being made a useful laser system will eventually be created, and that potential is worth the money.

Integrated Defense Systems, the division of Boeing responsible for the test, is one of the major players in the US weapons development industry with 70,000 employees worldwide. Putting lasers in the sky is just one of their goals, but it’s an important one. A closely related project, the Airborne Laser (ABL) is one of the leading candidates for missile defense during the boost phase. ABL could be, though it is still unproven, a means of defeating missile strikes from developing nuclear powers.

By killing nukes or saving lives through better precision, lasers have some considerable positive potential. However, you can’t watch a laser cut a hole in a truck without thinking of the damage the weapon could achieve against a person. Today, anti-personnel lasers largely see use in clandestine strikes against the eyes of pilots, not as fieldable weapons. The success of the recent test, however, shows that once tactical lasers like the ATL become cheap enough they could be used to devastating effect against living targets.

Laser sniping from an airplane is a scary prospect. With robotic weapons, you worry about removing humans from the decision to kill someone. With laser weapons, you worry about accountability. Long range and completely silent, a laser strike could kill a person and would probably not be recognized as an attack by those around him or her.

As armed conflicts evolve, modern militaries seem focused on selective and effective targeting. That is, they want to know who to kill and they want to hit just that person whereever they may be. Improved sensing, computer enhanced decision making, and tactical lasers seem poised to deliver that military goal. I have mixed feelings about the capability. Certainly you could save lives if the only people killed in a war were combatants, but distancing humans from the death they cause seems unlikely to improve moral decision making. As cool as the ATL is, it is still uncertain if it bodes well or ill for the future of warfare. And I sort of feel sorry for the truck.

[photo credit: Boeing]
[video credit: Boeing]

Inside the target chamber. Courtesy of NIF

Today marks the opening ceremony, with big names like Energy Secretary Steven Chu, laser pioneer Charles Hunt Townes, and even the Governator in attendance. Housed at the infamous Lawrence Livermore National Laboratory in California, the NIF was 12 years and 3.5 billion dollars in the making.  The facility covers three football fields, ten stories, and contains sixty miles of mirrors, fiber optics, crystals and light amplifiers. Funded by the Department of Energy, the NIF hopes to begin experiments next year.

So how does one go about creating a mini star? The NIF uses 192 high powered lasers, capable of delivering a two million joules of ultraviolet energy. From their source, the lasers travel over 1,000 feet through a series of amplifiers, exponentially increasing their power before they reach their destination: the spherical “target chamber.” Here, each laser in the room is pointed at a single drop of hydrogen fuel about the size of a BB pellet. By blasting the hydrogen with extreme heat simultaneously from all sides, the lasers will fuse the hydrogen together to form helium, a reaction that releases a whole lot of energy.

If a fusion reaction can produce enough energy to fuel itself (i.e. start a chain reaction), it has reached the point of ignition. The only man-made fusion reactions that have ever achieved ignition were anything but controlled; they were hydrogen bombs. For over fifty years, physicists have argued about whether or not fusion energy could ever be harnessed without blowing up in your face.  The NIF is built to solve that question.

Check out a video about the new facility:

Will it work?  No one is really sure. The facility can’t make enough energy for ignition yet, and might not ever be able to. To critics, this makes the NIF a massive (and expensive) gamble. Running the lab will cost about $140 million per year, which doesn’t even touch the 3.5 billion already invested. The construction process was rife with delays, setbacks, and budget increases (the project was initially priced at $1 billion). It will still take years of experimentation before the facility produces any real results, and the possibility of ignition is still a big, fat maybe.

The hydrogen fuel pellet targeted for fusion. Courtesy of NIF

The applications of this research are unbelievably diverse. Besides the ultimate goal of creating an energy source, the facility will be used to study how nuclear fusion takes place within both stars and at the core of planets. Our mini star could also provide some hints as to what happened around the time of the Big Bang, a tricky theory to test out in the lab. The NIF will also be used to national security ends, running simulations on the status of our aging nuclear arsenal. This is especially important given the nuclear testing moratorium established in 1992, making live bomb testing a no-no.

If the project succeeds, it could create a renewable, carbon-free energy source of unimaginable value.  To its critics, it’s an expensive wet dream of physicists that will never live up to its costs. To repeat the classic refrain of speculative science, time will tell. Personally, as a Bay Area resident, I’m pretty excited about the idea of having a small star burning about 30 miles from my house. Let’s just hope they earthquake-proofed the thing.

The University of Texis at Austin reports that Professor Adela Ben-Yakar and colleagues have developed a femtosecond laser “microscalpel” that is so precise that it can destroy a single cell while leaving nearby cells intact.  According to the article:

“Within a few years, Ben-Yakar expects to shrink the probe’s 15-millimeter diameter three-fold, so it would match endoscopes used today for laparoscopic surgery. The probe tip she has developed alsocould be made disposable — for use operating on people who have infectious diseases or destroying deadly viruses and other biomaterials.”

“Femtosecond lasers produce extremely brief, high-energy light pulses
that sear a targeted cell so quickly and accurately the lasers’ heat
has no time to escape and damage nearby healthy cells. As a result, the
medical community envisions the lasers’ use for more accurate
destruction of many types of unhealthy material. These include small
tumors of the vocal cords, cancer cells left behind after the removal
of solid tumors, individual cancer cells scattered throughout brain or
other tissue and plaque in arteries.”

“A commercially available femtosecond laser system and microscope was
developed recently for LASIK and other eye surgeries, but the system’s
bulk limits its usefulness. Ben-Yakar’s laboratory has overcome
technological challenges to create a microscope system that can deliver
femtosecond laser pulses up to 250 microns deep inside tissue. The
system includes a tiny, flexible probe that focuses light pulses to a
spot size smaller than human cells.”

Adela Ben-Yakar has had success using similar laser devices to cut the connections (the axons) between individual nerve cells in a hunt for genes that control nerve regrowth after injury.

Recently researchers have devised an alternative solution to nerve stimulation: zapping them with a laser beam. Laser based nerve stimulation overcomes many of the problems associated with electrical stimulation: it requires no physical contact with the nerve cells and the laser can be tuned to precisely hit only the nerve cells that are desired. Laser based nerve stimulation could unleash a revolution in our ability to interface with nerve cells. For example, the precision offered by laser interfacing with human nerves may aid efforts to develop prosthetic limbs that are as dexterous as real human limbs.

The Long:

This breakthrough in laser based nerve stimulation has created a flurry of press in recent months. In addition to the ieee article referenced above, another excellent article came from the researchers published by spie here. Interestingly, the exact mechanism by which laser light is able to cause neuron stimulation is unknown, as quoted here by the spie article:

“A conceptual understanding of how laser light stimulates neural tissues
is crucial for the further optimization of the technique, allowing it
to reach its full potential. The current hypothesis—based on a number
of mechanistic experiments—is that the laser activates nerves by a
transient, thermally induced mechanism. At the stimulation threshold,
experiments suggest that the maximum nerve-surface temperature increase
is less than 9°C, well below the 45–50°C tissue temperatures required
for the onset of tissue damage. Future experiments will reveal if
stimulation arises through a direct membrane interaction or an indirect
effect leading to membrane depolarization.”

The article offers a fantastic picture that demonstrates the superior nature of laser based stimulation over electrical stimulation in its ability to target only the desired nerve cells without accidentally stimulated nearby neurons. In the picture below we see that the electrical stimulation caused the target nerve to stimulate but also caused unwanted stimulation of nearby nerves. The laser based stimulation avoided this unwanted stimulation.