Navigation Links
Memory relies on astrocytes, the brain's lesser known cells
Date:7/28/2014

LA JOLLAWhen you're expecting somethinglike the meal you've ordered at a restaurantor when something captures your interest, unique electrical rhythms sweep through your brain.

These waves are called gamma oscillations and they reflect a symphony of cellsboth excitatory and inhibitoryplaying 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. 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. As expected, healthy mouse spent more time with a new item placed in its environment than it did with familiar items. 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 goneas 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 quickthey'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.


'/>"/>

Contact: Chris Emery
press@salk.edu
Salk Institute
Source:Eurekalert  

Related medicine news :

1. Eating Berries Might Help Preserve Your Memory
2. Scripps Research scientists show how memory B cells stay in class to fight different infections
3. Sleep Can Sharpen Your Memory
4. Nutrient mixture improves memory in patients with early Alzheimers
5. Nutrient Drink Might Boost Memory in Early Alzheimers: Study
6. Drug shown to improve memory in those with Down syndrome
7. Strobe eyewear training improves visual memory
8. Wayne State develops better understanding of memory retrieval between children and adults
9. Sleep improves memory in people with Parkinsons disease
10. Frequent MRI Scanner Exposure Might Affect Memory: Study
11. Mathematics or memory? Stanford study charts collision course in brain
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Memory relies on astrocytes, the brain's lesser known cells
(Date:6/26/2016)... ... June 26, 2016 , ... Brent Kasmer, a legally blind and certified personal trainer is helping ... fitness app. The fitness app plans to fix the two major problems leading the fitness ... size fits all type program , They don’t eliminate all the reasons people ...
(Date:6/25/2016)... Viejo, California (PRWEB) , ... June 25, 2016 , ... ... to fit their specific project," said Christina Austin - CEO of Pixel Film Studios. ... fully customizable and all within Final Cut Pro X . Simply select a ...
(Date:6/25/2016)... ... June 25, 2016 , ... Conventional wisdom preaches the ... In terms of the latter, setting the bar too high can result in disappointment, ... just slow progress toward their goal. , Research from PsychTests.com reveals ...
(Date:6/24/2016)... ... June 24, 2016 , ... The Pulmonary Hypertension Association (PHA) ... will receive two significant new grants to support its work to advance research ... anniversary by recognizing patients, medical professionals and scientists for their work in fighting ...
(Date:6/24/2016)... ... June 24, 2016 , ... People across the U.S. ... magazine’s Code Talker Award, an essay contest in which patients and their families pay ... be presented at the 2016 National Society of Genetic Counselors (NSGC) Annual Education Conference ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... and INDIANAPOLIS , June ... receiving a Lilly Diabetes Tomorrow,s Leaders Scholarship is any ... scholarship winners, announced today online at www.diabetesscholars.org ... type 1 diabetes stand in the way of academic ... supported the Foundation,s scholarship program since 2012, and continues ...
(Date:6/23/2016)... -- Guerbet announced today that it has been named a ... One of 12 suppliers to receive the ... of Premier members through exceptional local customer service and ... lower costs. "We ... customer service from Premier," says Massimo Carrara , ...
(Date:6/23/2016)... 2016  Experian Health, the healthcare industry ... patient payment and care experience, today announced ... and services that will enhance the breadth ... These award-winning solutions will enable healthcare professionals ... in an ever-changing environment and redefine front-office ...
Breaking Medicine Technology: