Posts Tagged ‘brains’
US Government Archived Bin Laden’s Sister’s Brain For DNA Comparison
It’s predictable that the U.S. government, not leaving anything to chance, used DNA to identify Osama Bin Laden’s body. What is more than a little creepy, is that they matched his DNA to that of his sister, who died several years ago of brain cancer, and whose brain the FBI has kept in its hall of brains since then.
The FBI had immediately subpoenaed her body upon her death, in the hopes that it could be used for this exact purpose. They preserved her brain as well as blood and tissue samples to create a DNA profile. This profile, among other things like facial recognition, was used to confirm that the man shot in the raid on the compound in Pakistan, was in fact Bin Laden. The DNA test was conducted in Afghanistan, after which Bin Laden was buried at sea.
Neuroscientists Engineer Mice That Make Better Decisions
Researchers at Columbia University engineered mice to produce a surplus of new neurons in the hippocampus. They found the mice were superb at learning to discriminate between experiences, which typically gets harder with age and with some anxiety disorders. Specifically, the mice were better able to differentiate between a chamber where they got a foot shock and a similar-looking chamber where they were safe.
Adult brains make new neurons all the time, a process called neurogenesis, but many of them don’t survive; certain diseases, like Alzheimer’s, inhibit their growth and function. Neuron creation can impact moods and learning abilities, so drugs that can boost their creation could be useful treatments for depression, anxiety and memory problems.
To enhance the mice brains, researchers led by Columbia neuroscience and pharmacology professor René Hen and postgraduate researcher Amar Sahay turned off a gene that kills new neurons in the adult brain, giving the mice a proliferation of new brain cells. This led to improved pattern separation, like distinguishing between the good and bad chambers. Treatments like this could be effective for things like post-traumatic stress disorder, Hen said in a — PTSD patients experience fear and other emotions when they are reminded of a similar bad experience.
“Even though I may remember 9/11, when I see an airplane over New York City, I am able to recognize that it’s a different situation and process it accordingly, while someone in the same situation with PTSD may re-experience the traumatic memory of 9/11 and have a panic attack,” Hen said. Novel neurons could help the PTSD patient separate the events, Hen added.
The mice with enhanced neurogenesis abilities didn't show any outward anti-anxiety behavior — like exploring potentially dangerous situations — until they got some exercise: four weeks of running on hamster wheels.
The research suggests that combined with exercise, drugs that allow improved neurogenesis could help improve cognitive function — an interesting treatment for anything from neurodegenerative disorders to simple anxiety.
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Talk To The Hand: A New Interface For Bionic Limbs
Light bridges the communication gap between man and machine.
Previously, scientists surgically connected electrodes to the nervous system, but they seemed to harm the body’s tissues, making the implant fail within months. In 2005, scientists discovered that they could stimulate a neuron to send a message by shining infrared light on it. Last September, DARPA, the Pentagon’s R&D branch, awarded $4 million to a project led by Southern Methodist University engineers to attempt to connect nerves to artificial limbs using fiber optics.
The team suspects that flexible glass or polymer fiber optics will be more flesh-friendly than rigid electrodes. In addition, optical fibers transmit several signals at once, carrying 10 times as much data as their electrical counterparts. “Our goal is to do for neural interfaces what fiber optics did for the telecom industry,” says electrical engineer Marc Christensen, who is leading the SMU group. Transmitting more information faster should give bionic limbs more lifelike movements.
This month, the team will implant optical fibers to stimulate a rat’s rear leg. If it works, Christensen says, in about a decade, robotic arms could be as graceful as Steve Austin’s six-million-dollar one.
How Artificial Nerves Work
Sensing The Limb
When someone’s prosthetic hand touches a ball, for example, it would trigger an optical fiber in the arm to pulse a pattern of infrared light like Morse code. These light messages stimulate a sensory nerve to fire in a similar pattern, instructing the brain that the hand is feeling a round object.
Moving The Limb
Thinking about squeezing the ball sends electrical impulses from the brain to a motor nerve. When it reaches the optical fiber implanted in the nerve, the signal deforms thousands of the fiber’s spheres. This changes the pattern of light in the fiber, which instructs the prosthetic hand to grip the ball.
New Imaging Method Opens a Long-Term Porthole Into the Deep Brain
Whole-brain scans like functional magnetic resonance imaging allow scientists to watch brain activity unfold, but they don’t provide the level of detail you might need to watch degenerative diseases or cancer at work. Traditional light microscopes can only go so far, however, penetrating about 1/32 of an inch of tissue before it’s too dark to see. Scientists have been able to peer deeper by using micro-optics, but this is also just a snapshot of one moment in time, and it’s almost impossible to return to the same spot twice. What’s more, the act of taking a peek — shoving a micro-optical device deep into the brain — can cause injury or infection.
Mark Schnitzer, a Stanford biology and applied physics professor, outlines a new option in this week’s issue of Nature Medicine. It starts with implanting tiny glass tubes, about half the width of a grain of rice, into the deep brain of a mouse. Once the tubes are in place, the brain is protected from the outside environment, and scientists can stick a tiny endoscope inside. The glass tube has a window on the end through which scientists can image neurons and monitor them over time.
“It's a bit like looking through a porthole in a submarine,” Schnitzer said in a Stanford news release.
The technique allows researchers to monitor individual cells as well as changes in individual animals, by comparing healthy tissue to diseased tissue. It could help researchers better understand aggressive brain cancers, for instance, which are known to be more deadly when they start in the deep brain as opposed to the surface. The method could be used for deep-tissue imaging studies in other parts of the body, too, Schnitzer said.
“We’re bringing the power of the microscope to tissues that lie beneath the penetration of light into the brain,” he said.
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Improve Your Math Skills With An Electric Jolt To Your Brain*
Patients were asked to learn new symbols to represent numbers, then, while they were on TDCS, they attempted to organize the numbers. Participants whose brains were being stimulated demonstrated an improved ability to perform the task. The amazing part is that, when tested again six months later, they retained their higher performance level. The current helps the affected nerves to fire more quickly, making it easier to learn information.
The next trials will involve patients who have lower-than-average number processing skills, and Oxford scientists hope to one day develop a device to deliver TDCS. While it may be some time before such brain-zapping is widely administered, this treatment could help the significant portion of the population (nearly 20 percent) with moderate to severe math disability, and possibly those with difficulty in other subjects as well.
* Do not zap your brain with electricity except under professional supervision.
Improve Your Math Skills With An Electric Jolt To Your Brain*
Patients were asked to learn new symbols to represent numbers, then, while they were on TDCS, they attempted to organize the numbers. Participants whose brains were being stimulated demonstrated an improved ability to perform the task. The amazing part is that, when tested again six months later, they retained their higher performance level. The current helps the affected nerves to fire more quickly, making it easier to learn information.
The next trials will involve patients who have lower-than-average number processing skills, and Oxford scientists hope to one day develop a device to deliver TDCS. While it may be some time before such brain-zapping is widely administered, this treatment could help the significant portion of the population (nearly 20 percent) with moderate to severe math disability, and possibly those with difficulty in other subjects as well.
* Do not zap your brain with electricity except under professional supervision.
Instant Expert: Rebuilding Human Minds
Scientists hope to strengthen aging brains by tweaking the behavior of DNA
Memory Lost, Memory Gained
HOW WE MAKE MEMORIES
The process of forming long-term memories—those that persist for more than a few dozen seconds—is poorly understood, but here’s what we know: Neuroscientists have evidence that the brain’s hippocampus is central to the process. To consolidate a memory, a cascade of electrical pulses fire across the gaps between neurons, called synapses. This triggers the release of neurotransmitters, which form new connections between neighboring neurons. But neurotransmitters can’t be synthesized without each cell tapping into its DNA.
HOW GENES AFFECT MEMORY
Long-term memories are less likely to be formed if certain genes are not activated, which is why it’s at the genetic level that scientists are trying to effect change. Normally, inside cell nuclei, DNA tightly wraps around a protein spool, called a histone. A small molecule called an acetyl group attaches to a particular histone known as H4. When this happens, the DNA wrapped around the spool loosens slightly. The loosening of the DNA makes it more available for the biological process, called transcription, that permits the gene to be expressed into neurotransmitters.
HOW MEMORY IS LOST
In age-related memory loss, the H4 histones don’t have enough acetyl groups attached to them. DNA remains tightly wound around the histone spool, so the genes on the spool that control memory formation remain suppressed.
HOW WE MIGHT GET IT BACK
To reverse the memory loss, doctors inject a compound called a histone deacetylase inhibitor. It ensures that the H4 histones have plenty of attached acetyl groups, so the DNA wrapped around the histone once again becomes available for transcription. The memory-formation instructions encoded in the DNA can be used to make proteins, helping restore memory formation.
FAQs
I’M STILL PRETTY YOUNG, SO WHY CAN'T I REMEMBER WHERE I PUT MY KEYS?
Cut yourself some slack. Occasional memory glitches can be caused by something as simple as not paying attention to your surroundings, lowering the likelihood that a particular memory will be encoded. Even though these glitches are more common after 40, in most cases, they don’t signify the onset of early senility. You probably don’t need to worry unless you start forgetting a good portion of your vocabulary or losing the capacity to do easy math problems.
HOW CAN I TELL IF I MIGHT LOSE MY MEMORY LATER IN LIFE?
You can’t know for sure. But you may be more at risk if you have high cholesterol, a family history of dementia, drink heavily, or participate in sports that involve multiple blows to the head.
Essential Jargon
HISTONE: Histones are crucial in the process of condensing and packing DNA within a cell’s nucleus. An octa-mer of histones package DNA into a structure called a nucleosome. Histone H4 is one of five histone groups.