Memory relies on astrocytes, the brain’s lesser known cells
When you’re expecting something—like the meal you’ve ordered at a restaurant—or when something captures your interest, unique electrical rhythms sweep through your brain.
These waves are called gamma oscillations and they reflect a symphony of cells—both excitatory and inhibitory—playing together in an orchestrated way. Though their role has been debated, gamma waves have been associated with higher-level brain function, and disturbances in the patterns have been tied to schizophrenia, Alzheimer’s disease, autism, epilepsy and other disorders.
Now, new research from the Salk Institute shows that little known supportive cells in the brain known as astrocytes may in fact be major players that control these waves.
In a study published July 28 in the Proceedings of the National Academy of Sciences, Salk researchers report a new, unexpected strategy to turn down gamma oscillations, by disabling not neurons but astrocytes—cells type traditionally thought to provide more of a support role in the brain. In the process, the team showed that astrocytes, and the gamma oscillations they help shape, are critical for some forms of memory.
"This is what could be called a smoking gun," says co-author Terrence Sejnowski, head of the Computational Neurobiology Laboratory at the Salk Institute for Biological Sciences and a Howard Hughes Medical Institute investigator. "There are hundreds of papers linking gamma oscillations with attention and memory, but they are all correlational. This is the first time we have been able to do a causal experiment, where we selectively block gamma oscillations and show that it has a highly specific impact on how the brain interacts with the world."
A collaboration among the labs of Salk professors Sejnowski, Inder Verma and Stephen Heinemann found that activity in the form of calcium signaling in astrocytes immediately preceded gamma oscillations in the brains of mice. This suggested that astrocytes, which use many of the same chemical signals as neurons, could be influencing these oscillations.
To test their theory, the group used a virus carrying tetanus toxin to disable the release of chemicals released selectively from astrocytes, effectively eliminating the cells’ ability to communicate with neighboring cells. Neurons were unaffected by the toxin.
After adding a chemical to trigger gamma waves in the animals’ brains, the researchers found that brain tissue with disabled astrocytes produced shorter gamma waves than in tissue containing healthy cells. And after adding three genes that would allow the researchers to selectively turn on and off the tetanus toxin in astrocytes at will, they found that gamma waves were dampened in mice whose astrocytes were blocked from signaling. Turning off the toxin reversed this effect.
The mice with the modified astrocytes seemed perfectly healthy. But after several cognitive tests, the researchers found that they failed in one major area: novel object recognition. A healthy mouse spent more time with a new item placed in its environment than it did with familiar items, as expected.
In contrast, the group’s new mutant mouse treated all objects the same. “That turned out to be a spectacular result in the sense that novel object recognition memory was not just impaired, it was gone—as if we were deleting this one form of memory, leaving others intact,” Sejnowski says.
The results were surprising, in part because astrocytes operate on a seconds- or longer timescale whereas neurons signal far faster, on the millisecond scale. Because of that slower speed, no one suspected astrocytes were involved in the high-speed brain activity needed to make quick decisions.
"What I thought quite unique was the idea that astrocytes, traditionally considered only guardians and supporters of neurons and other cells, are also involved in the processing of information and in other cognitive behavior," says Verma, a professor in the Laboratory of Genetics and American Cancer Society Professor.
It’s not that astrocytes are quick—they’re still slower than neurons. But the new evidence suggests that astrocytes are actively supplying the right environment for gamma waves to occur, which in turn makes the brain more likely to learn and change the strength of its neuronal connections.
Sejnowski says that the behavioral result is just the tip of the iceberg. “The recognition system is hugely important,” he says, adding that it includes recognizing other people, places, facts and things that happened in the past. With this new discovery, scientists can begin to better understand the role of gamma waves in recognition memory, he adds.
i hate this
this is terrifying
All horses are the prepared vessels of an angry god.
(Source: actionactioncut, via omgtsn)
People look down on McDonald’s employees but fail to realize that if all these folks left McDonald’s and pursued “better careers” your ass wouldn’t be able to get a McDouble with an Oreo McFlurry at 3am.
You can’t demand a service while simultaneously degrading those who provide it for you.
You can’t demand a service while simultaneously degrading those who provide it for you.
Have you ever been to earth?
On earth, we use the word “burrito” to describe a tortilla filled with things you eat. Pretty simple stuff, and I’m surprised you at least got that part right. My burrito was, in fact, filled with food. In this, you and I agree and are friends. But this is also where my lifelong hatred begins for you and anyone else whose brain has been repeatedly scrubbed with the same mixture of bleach and Pop Rocks as yours has. Because that should have killed you, but left you around long enough to do what you did to me today. Let me explain:
You’re an idiot.
Let me further explain:
Burritos are eaten from one end to the other. So that means when you assemble a burrito with motherfucking ZONES of ingredients going that direction, you create a disgusting experience for the burrito’s end user. When you make a burrito, you should put the ingredients in layerslengthwise. That way, every bite has AT LEAST A FUCKING CHANCE of getting at least two types of ingredients, and there is little chance of becoming almost hopelessly trapped in a goddamned cilantro cavern.
Have you ever eaten one of the things you make all fucking day? You should try one. They are pretty good WHEN YOU ARE NOT WILLING YOURSELF THROUGH THE FUCKING EMPIRE OF SOUR CREAM ONLY TO END UP IN LETTUCE COUNTRY.
When you eat a burrito, you don’t stand it up and bite down on it lengthwise like a fucking Rancor. Humans can’t usually dislocate their jaws, and I’m not a fucking pelican. But you must think that’s how it’s done, since that would be THE ONLY FUCKING WAY to take a bite of your crapstrosity and have it taste like a burrito.
And guess what else, player? You probably can’t guess anything, because I’m pretty sure you’re just a mop with a hat on it that fell over and spilled some shit into a tortilla, but just in case, here’s what:
Humans also don’t eat burritos like fucking corn on the cob. Like a fucking typewriter from one end to the other a little at a time and then DING next line. But today I wish I had tried that. Because at least THEN I would be able to eat some rice, then beans, then be all like HEY BEANS I’LL BE RIGHT BACK JUST GOING OVER HERE TO THE GUACAMOLE FOR A SECOND.
My experience was more like HEY BEANS IT’S JUST GOING TO BE YOU AND I FOR A MINUTE UNTIL I CAN FUCKING EXCAVATE THE RICE FROM BENEATH YOU BUT BY THEN YOU WILL BE A FADING MEMORY OH HEY I WAS WRONG I’M IN THE FUCKING CHEESEOSPHERE NOW RICE MUST BE NEXT I HOPE IT’S NOT ANOTHER FUCKING SALSA POCKET.
You built this thing like a fucking pack of LifeSavers.
And don’t even fucking think I’m about to open this shit up and re-engineer your nonsense 90 degrees. I ALREADY PUT A HOLE IN IT WITH MY FUCKING MOUTH. YEAH. THAT’S HOW I DISCOVERED YOU FUCKING SUCK AT LOOKING AT THINGS. I AM NOT GOING TO DO FUCKING TORTILLA ORIGAMI TO GET THIS SHIT BACK TOGETHER, ONLY TO END UP WITH A BURRITO THAT’S BEEN SHOT IN THE GUT AND IS BLEEDING YOUR INEPTITUDE.
What’s that? I should ask you to mix it up first next time? IS THIS JAMBA JUICE? I DON’T WANT TO DRINK MY FUCKING BURRITO THROUGH A BENDY STRAW, AND I DON’T WANT A PILE OF BURRITO SOUP IN A FLOUR CAN.
I just want a burrito.
You’re the worst thing that has ever happened to the universe, you owe everyone everywhere an apology for this burritobomination, and I hope your babies look like monkeys.
UPDATE FOR EVERYONE WHO SAID “JUST EAT IT WITH A FORK”:
A fucking fork?
I DIDN’T ORDER THE FUCKING COBBURRITO SALAD.
If anyone ever handed me a burrito with a fork, THEY WOULD BE WEARING A BRAND NEW BURRITO HAT FROM MY FALL COLLECTION TEN SECONDS LATER.
That’s like buying a car and having them hand you a fucking wrench with the keys. Like YEAH WE KNOW THIS MOTHERFUCKER’S GOING TO EXPLODE AND BE SPREAD ACROSS EIGHT LANES AS SOON AS YOU HIT THE GAS, BUT SHIT, WE GAVE YOU A WRENCH, SO BE COOL.
Jesus already gave me two burrito forks. One at the end of each arm. They’re called fucking HANDS.
A fork. My god. I haven’t cried since I was six, but I’m fucking sobbing now.
People eat burritos with forks?
God is sorry he made us.
I always need this on my blog.
I can’t be laughing this hard in the morning.