Deep in your brain there are probably several thousand neurons that will respond only to the sight of Lady Gaga. Several thousand others probably only crackle to the sight of Justin Bieber. It might be nice to reassign those neurons to loftier thoughts. For now, though, neurology can’t help you. What neurology can do for you (if you’re up for a little invasive brain surgery) is let you use those Gaga and Bieber neurons to control a computer.
A team of researchers has built on the previous discovery that specific neurons respond to the images of specific people–like Lady Gaga, or your grandmother. To harness these neurons, the researchers tried out an ingenious brain-machine interface based on images of celebrities who triggered particularly strong responses in 12 patients.
A patient could bring a digital image of a celebrity (like Marilyn Monroe) into the foreground by consciously focusing on the image, which meant that the celebrity-associated neurons were firing. As they describe in a paper in Nature, the patients quickly got the hang of it, activating patches of neurons at will. This has led researchers to wonder if people could one day control devices simply by visualizing certain people, things, or concepts.
You can get the rest of the story on this fascinating but intrusive technology, and can also see a video that Carl made about the experiments, at The Loom.
Ketamine for bipolar disorder. LSD for depression. It’s been a busy month for psychedelic drugs in the laboratory, as several studies showed that these drugs typically used recreationally—and illegally—affect the brain in ways that could make them useful for treating mental illness.
First came a small study in the Archives of General Psychiatry that we covered earlier this month, in which scientists tested 18 patients who on average had tried seven kinds of drugs to treat their bipolar disorder. When the researchers gave them small doses of ketamine—a powerful anesthetic that people use recreationally for the hallucinogenic side effects—the patients’ depressive symptoms lessened within a matter of minutes.
Astrocytes, it was long believed, were little more than the scaffolding of the brain—they provided a support structure for the stars of the show, the neurons. But a study out in this week’s Science is the latest to suggest that this is far from the whole story. The study says that astrocytes (whose “astro” name come from their star-shape) may in fact play a critical role in the process of breathing.
Astrocytes are a type of glial cell — the most common type of brain cell, and far more abundant than neurons. “Historically, glial cells were only thought to ‘glue’ the brain together, providing neuronal structure and nutritional support but not more,” explains physiologist Alexander Gourine of University College London, one of the authors of the study. “This old dogma is now changing dramatically; a few recent studies have shown that astrocytes can actually help neurons to process information” [Nature].
Gourine’s team peeked into the brains of rats to figure out the connection between astrocytes and breathing. In humans and in rodents, the level of carbon dioxide in the blood rises after physical activity. The brain has to adjust to this, setting the lungs breathing harder to expel that CO2.
Eleanor Maguire can’t read your mind. But she’s getting closer.
Two years ago the neuroscientist’s team used functional MRI scans of the brain to predict where in a virtual reality environment a person was “standing” just by looking at their brain activity. And now, in a study for Current Biology, she’s used fMRI scans, interpreted by a computer algorithm, to pick out the patterns of brain activity that indicate whether a person is remembering one movie versus another.
An fMRI scan measures the brain’s blood flow—associated with neuron activity—on the scale of voxels, three-dimensional “pixels” that each include roughly 10,000 neurons. The algorithm then interprets the changes voxel by voxel to learn the brain’s patterns of activity over time [ScienceNOW]. In this experiment, Maguire’s team showed their 10 participants three different movies. Each was short, only about seven seconds, but featured a different actress doing a different simple activity, like mailing a letter or drinking coffee. The scientists then asked the subjects remember the films while the team scanned their brains.
Thanks to a little technological ingenuity, we may soon get a look at what exactly is happening in the flying brain. In the journal Nature Neuroscience, Caltech researchers document how they managed to monitor the brain activity of fruit fly in flight.
“The challenge was to be able to gain access to the brain in a way that didn’t compromise the animal’s ability to fly, or to perform behavior,” said study researcher Michael Dickinson of Caltech. “We couldn’t just rip the brain out of the body and put it into a dish” [LiveScience]. Researchers have previously studied activity in the tiny brain of a living fruit fly, but only when it was restrained. Dickinson’s team created a way to look inside while the bug was flying around.
Cells just keep surprising us. Researchers have now found that, with a little genetic tweaking, they can transform skin cells into brain cells without having to first reprogram them to act like multipurpose stem cells. This finding, the first of its kind, is in this week’s edition of the journal Nature.
The researchers did their study on mice. They induced the change by inserting only three genes into cultured skin cells. Once those three genes activated, the skin cells converted into fully functioning nerve cells that even formed synapse connections with the other converted nerve cells [Popular Science]. That change took less than a week, a surprisingly rapid rate. Said team member Marius Wernig: “These are fully functional neurons. They can do all the principal things that neurons in the brain do” [AFP].
Scientists have figured out a way to switch brain cells on and off like light bulbs, but instead of using a clapper, they’re using microbial proteins and lasers. Ed Boyden, a neuroscientist at the Massachusetts Institute of Technology, has developed a way to shut down parts of a brain just by shining light on them. When the light is turned off, the brain switches back on [Forbes].
The research team says their technology will help neuroscientists probe the brain’s circuitry by silencing certain regions and studying the effects. The technique, which was described in the journal Nature, could one day be used to shut down overactive regions of the brain often found in people with epilepsy, depression, Parkinson’s disease, and blindness.
Scientists recently used treadmill exercise, drugs, and electrical stimulation to train paralyzed rats to walk once again, demonstrating a way to possibly treat spinal injuries in humans, which at present are basically untreatable.
In a spinal injury, the neural circuits connecting the brain to the muscles that control walking become damaged or severed, leaving an individual paralyzed. In able-bodied people, these “walking circuits” spring into action when they receive a signal from the brain, but if the spinal cord is damaged, the message from the brain never arrives. When contact with the brain is lost, the circuits shut down [The Guardian]. In the study, published in Nature Neuroscience, researchers manipulated these circuits and produced movement that was “almost indistinguishable” from normal walking. See for yourself in the embedded video.
Experiments conducted on squid brains in the early days of neuroscience created misunderstandings about the workings of the human brain that have persisted for 70 years, according to a new study. While the squid experiments did shed light on how messages are transmitted between brain cells with electrochemical signals (and led to a Nobel Prize for the experimenters), researchers are just now realizing that the results gave scientists a confused idea about the efficiency of neurons.
The story begins seventy years ago when a pair of British physiologists, Alan Hodgkin and Andrew Huxley, took the first stab at figuring out how neurons transmit electrical signals, known as action potentials. Because most neurons are small–in humans, a cubic millimeter of gray matter can contain 40,000 neurons–the duo turned to squid, which contain a giant axon, the long thin part of a neuron through which action potentials travel [ScienceNOW Daily News]. Those early experiments found that transmitting the action potential along the axon was a very inefficient process that used a great deal of energy, and neuroscientists ever since have assumed that mammal brains had the same inefficient wiring.
Researcher Henrik Alle, lead author of the new study published in Science, decided to reexamine the old assumptions. “I saw this old work,” says Alle. “I thought I cannot believe personally that nature would waste such energy.” Alle figured that nature would have made the process more efficient in mammals, whose brains send a huge number of messages [NPR News].
A chemical compound similar to the blue food dye found in blue M&Ms and blue Gatorade could one day be used to treat people with spinal injuries, and could reduce damage and improve mobility, according to a new study. Researchers found that when they injected the compound Brilliant Blue G (BBG) into rats suffering spinal cord injuries, the rodents were able to walk again, albeit with a limp. The only side effect was that the treated mice temporarily turned blue [CNN].
The same research team had previously shown that ATP, a vital energy source that keeps the body’s cells alive, quickly pours into the area surrounding a spinal cord injury after it occurs. Unfortunately, the release of ATP at hundreds of times the normal level kills off healthy, uninjured motor neuron cells by flooding them with a deluge of molecular signals, making the initial injury worse [BBC News]. In the new experiment, described in the Proceedings of the National Academy of Sciences, the blue compound prevented ATP from latching on to the motor neuron cells, and therefore prevented the secondary damage that occurs in the hours after a spine injury.
In a new study, researchers attached electrodes to individual neurons in monkeys’ brains and then rerouted those neuronal signals through a brain-machine interface, which converted them into electrical signals that controlled the monkeys’ own paralyzed muscles. Researchers say this roundabout feat of bioengineering could eventually lead to new treatments and prosthetics for paralyzed people.
The implant exploits the fact that even when the neural connection between a brain region and the muscles it controls is severed or damaged by, say, a stroke or spinal injury, the controlling neurons remain active. For example, people living with quadriplegia who try to move their arm still generate arm-movement signals in the motor cortex of their brain, even after several years of paralysis [New Scientist]. The new study is the first to send the signals back to the user’s own muscles, as opposed to related research in which the signals are fed into electronic devices.
A small study has found that the brains of men and women are wired differently in a region that is related to speech, memory, and hearing. Researchers studied the brain tissue from four men and four women who were all having a small portion of their brains excised as a treatment for epilepsy. They found that in the brain region called the temporal neocortex, men have a higher density of synapses, which are the connection points between brain cells.
For many years, scientists have searched for structural variations between men’s and women’s brains to explain psychological studies showing that, overall, the sexes think and act differently. Past studies found differences in brain mass and neuron density, but “they were hyped and untrustworthy,” [neuroscientist Edward] Jones says. This study is meticulously detailed, he notes. It is the first to show gender differences on such a fine scale — at the synapse [Science News].
Researchers have gotten an amazingly close look at the human brain’s methods of short-term memory formation and recollection. A new study has examined the activity of individual brain cells, and found that the same neurons that fire when a person gets their first look at something fire again when they recall it.
Scientists at the University of California, Los Angeles, (U.C.L.A.) showed 13 volunteers—epilepsy patients with therapeutic electrodes implanted in their brains—several five- to 10-second clips from videos such as The Simpsons. The researchers found that a small sample comprising some 50 neurons in the hippocampus and entorhinal cortex (memory centers in the brain) fired in distinctive repeatable patterns that differed for each clip [Scientific American]. A few minutes later, when researchers asked the volunteers to think back to the film clips and say what came to mind, the neurons fired in the same distinct patterns when they mentioned each clip.
Researchers have built a “biological brain” for a robot using a dish full of rat neurons, and have harnessed the neurons’ electric signals to navigate the robot around a pen. Researchers say the experiment should add to their understanding of how brain cells function, and could provide insight into what goes wrong in neurons affected by diseases like Alzheimer’s and Parkinson’s.
The robot’s controller nestles inside a small pot containing a pink broth of nutrients and antibiotics. Inside that pot, some 300,000 rat neurons have made – and continue to make – connections with each other. As they do so, the disembodied neurons are communicating, sending electrical signals to one another just as they do in a living creature [New Scientist]. The neurons’ automatic drive to connect and communicate may be an indication of how sturdy brain cells are; researcher Steve Potter, who has been involved in similar experiments, says that brain cells have “evolved to reconnect under almost any circumstance that doesn’t kill them” [Telegraph].
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
From Carl Zimmer:
Ketamine
Astrocytes, it was long believed, were little more than the scaffolding of the brain—they provided a support structure for the stars of the show, the neurons. But a 
Eleanor Maguire can’t read your mind. But she’s getting closer.
Thanks to a little technological ingenuity, we may soon get a look at what exactly is happening in the flying brain. In the journal Nature Neuroscience, Caltech researchers 
Cells just keep surprising us. Researchers have now found that, with a little genetic tweaking, they can transform skin cells into brain cells without having to first reprogram them to act like multipurpose stem cells. 
Scientists have figured out a way to switch brain cells on and off like light bulbs, but instead of using a clapper, they’re using microbial proteins and 
Experiments conducted on squid brains in the early days of neuroscience created misunderstandings about the workings of the human brain that have persisted for 70 years, according to a new study. While the squid experiments did shed light on how messages are transmitted between brain cells with electrochemical signals (and led to a 
A chemical compound similar to the blue food dye found in blue M&Ms and blue Gatorade could one day be used to treat people with spinal injuries, and could reduce damage and improve mobility, according to a new study. Researchers found that when they injected the compound Brilliant Blue G (BBG) into rats suffering spinal cord injuries, the rodents were able to walk again, albeit with a limp. The only side effect was that the treated mice temporarily turned blue [
In a new study, researchers attached electrodes to individual 
A small study has found that the brains of 
Researchers have gotten an amazingly close look at the human brain’s methods of short-term 
Researchers have built a “biological brain” for a 
