PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Penn-led team prevents memory problems caused by sleep deprivation

Penn-led team prevents memory problems caused by sleep deprivation
2014-11-19
(Press-News.org) Sleep is a critical period for memory consolidation, and most people don't get enough. Research has shown that even brief periods of sleep deprivation can lead to deficits in memory formation.

In a new study, published in the Journal of Neuroscience, a team led by scientists from the University of Pennsylvania found that a particular set of cells in a small region of the brain are responsible for memory problems after sleep loss. By selectively increasing levels of a signaling molecule in these cells, the researchers prevented mice from having memory deficits.

Robbert Havekes was the lead author on the study. He is a research associate in the lab of Ted Abel, the study's senior author and Brush Family Professor of Biology in Penn's School of Arts & Sciences. Coauthors from the Abel lab included Jennifer C. Tudor and Sarah L. Ferri. They collaborated with Arnd Baumann of Forschungszentrum Jülich, Germany, and Vibeke M. Bruinenberg and Peter Meerlo of the University of Groningen, The Netherlands.

In 2009, a group from Abel's lab published a study in Nature that identified the cyclic AMP, or cAMP, signaling pathway as playing a role in sleep-loss-associated memory problems. Whereas depriving mice of sleep impaired their spatial memory, restoring levels of cAMP in their brain prevented this effect.

"The challenge following this important study," Abel said, "was to determine if the impact of sleep deprivation was mediated by particular regions of the brain and particular neural circuits. We suspected that the hippocampus, the brain region that mediates spatial navigation and contextual memory, was critical."

In the current work, they set out to answer these questions. They targeted excitatory neurons because of their importance in transmitting signals in the brain and the fact that their functioning relies on cAMP signaling. The limitation of previous studies was that they lacked a way to increase cAMP in just one area of the brain in a cell-type specific fashion. Havekes, Abel and colleagues devised a way of doing this that they term a "pharmacogenetic" approach, blending genetic modification and drug administration.

They engineered a non-pathogenic virus to harbor the gene encoding the receptor for the protein octopamine, which triggers cAMP pathway activation in fruit flies but is not naturally found in the brains of mice. The researchers injected this virus into the hippocampus of mice so that the excitatory neurons in that region alone would express the octopamine receptor.

"It sounds weird. Why would you put a receptor there that is never going to be activated?" Havekes said. "The trick is, you follow that up by giving mice the ligand of the receptor, which is octopamine, and that will activate the receptors only where they are present."

The team confirmed that only the excitatory hippocampal neurons expressed the receptor and that they could selectively increase cAMP levels in only these cells by giving the mice a systemic injection of octopamine.

"This way, we could manipulate the cAMP pathways that we previously saw being affected by sleep deprivation but selectively in specific neural circuits in the brain," Havekes says.

With this pharmacogenetic tool in hand, Havekes, Abel and colleagues began the sleep deprivation tests with the mice expressing the octopamine receptor in their hippocampus. First the researchers trained mice in a spatial memory task. They put them in a box that had three different objects, each in a distinct location.

Then, because previous research had shown that cAMP signaling contributes to hippocampus-dependent memory consolidation in two time windows -- first directly after training and again three to four hours after training -- the researchers gave mice in the experimental groups injections of octopamine in both of these windows to boost cAMP levels.

Mice receiving the cAMP boost were divided into two groups: One was left to sleep undisturbed, while the other was sleep-deprived for five hours by gently tapping their cage or rearranging their bedding.

One full day after the initial training, all of the mice were tested again. This time, there was a twist: one of the objects originally in the box had been moved to a new location.

"If the mice had learned and remembered the location of the objects during their training, then they would realize, okay, this is the object that has moved, and they'll spend more time exploring that particular object," Havekes explained. "If they didn't remember well, they would explore all the objects in a random fashion."

The researchers found that the sleep-deprived mice that received the octopamine injections spent more time exploring the object that had moved, just as mice that had not been sleep deprived did. On the other hand, sleep-deprived mice that didn't express the receptor explored all the objects at random, a sign that they had failed to remember the locations of the objects from their initial training as a result of the brief period of sleep deprivation.

"What we've shown is this memory loss due to sleep deprivation is really dependent on misregulation of cAMP signaling in the excitatory neurons of the hippocampus," Havekes said.

As a next step, the group would like to explore what cAMP is doing to help consolidate memory. They would also like to investigate how other cell types in the brain, such as astrocytes, might be affected. And finally, while this study focused on the impact of a brief period of sleep deprivation, Havekes is curious to know how not getting enough sleep on a daily basis, as is more similar to human experiences, might be affecting memory.

"Thinking about people who do shift work or doctors who work long hours, if we can tackle the cognitive problems that result from sleep loss, that would be a great thing," Havekes said.

"At least in the mouse using these sophisticated tools, we're able to reverse the negative impact of sleep deprivation on cognition," Abel said.

INFORMATION:


[Attachments] See images for this press release:
Penn-led team prevents memory problems caused by sleep deprivation

ELSE PRESS RELEASES FROM THIS DATE:

Cedars-Sinai study of Lou Gehrig's disease shifts 'origin' focus to brain's motor neurons

2014-11-19
LOS ANGELES (STRICTLY EMBARGOED UNTIL 5 P.M. EST on NOV. 11, 2014) - Lou Gehrig's disease, also known as amyotrophic lateral sclerosis, or ALS, might damage muscle-controlling nerve cells in the brain earlier in the disease process than previously known, according to research from the Cedars-Sinai Board of Governors Regenerative Medicine Institute. The findings, published in the Nov. 12 Journal of Neuroscience, could shift researchers' attention from the spinal cord to the brain's motor cortex as the disease's initial point of dysfunction. "In this study, we show the ...

Home exercise can ease hopelessness in coronary heart disease patients

2014-11-18
Home exercise can ease feelings of hopelessness in people with coronary heart disease, according to a small study presented at the American Heart Association's Scientific Sessions 2014. Feeling hopeless can be dangerous because it can discourage people from taking healthful steps such as exercising or quitting smoking, said Susan L. Dunn, Ph.D., R.N., lead author of the study and a professor of nursing at Hope College in Holland, Michigan. People with hopelessness may also suffer from depression, which is marked by a loss of interest in activities they normally enjoy. "For ...

New wireless ECG saves treatment time for people with severe heart attacks

2014-11-18
A new trans-satellite wireless 12-lead ECG can identify the most severe type of heart attack swiftly and save significant time from ambulance to angioplasty, according to research presented at the American Heart Association's Scientific Sessions 2014. An ECG measures the electrical activity of the heart and helps medical personnel determine if a person had an ST-elevation myocardial infarction (STEMI). Angioplasty, also known as percutaneous coronary intervention (PCI), is a procedure in which an inflatable balloon opens a blocked artery to restore blood flow to the heart. During ...

People who gained weight after quitting smoking still had lower death risk

2014-11-18
In a small study in Japan, people who stopped smoking didn't face increased death risk if they gained weight, according to research presented at the American Heart Association's Scientific Sessions 2014. "Quitters had a significantly lower risk of death compared to smokers regardless of their weight change after they stopped smoking," said Hisako Tsuji, M.D., lead author of the study. Researchers compared deaths from all causes in 1,305 Japanese adults who quit smoking to deaths among 2,803 Japanese smokers. Participants in both groups were 65 percent men, average age ...

Education and feedback may help improve heart health among high-risk groups

2014-11-18
Using a smart phone app for education and feedback about heart-healthy behavior may decrease the risk for heart and blood vessel disease among young black women, researchers said in a pilot feasibility study presented at the American Heart Association's Scientific Sessions 2014. "We need to raise awareness among women and their healthcare providers of gender and racial differences in cardiovascular disease," said Jo-Ann Eastwood, Ph.D., study lead author and associate professor at the University of California, Los Angeles School of Nursing. "Women are social by nature, ...

Patients counseled on genetic heart disease risk feel they have more control over fate

2014-11-18
Adults counseled on their genetic risk of coronary heart disease believe they have more control over their fate, according to research presented at the American Heart Association's Scientific Sessions 2014. Researchers examined the impact of disclosing risk of 10-year heart disease with or without genetic risk information to 207 patients (48 percent male, average age 58) participating in Myocardial Infarction GENES (MI-GENES), a randomized controlled study. The study's key elements included a risk score based on established risk factors and a genetic risk score based ...

Healthy diet linked to decreased blood-pressure measurements

2014-11-18
A heart-healthy diet is related to decreased blood pressure measurements, researchers said in a study presented at the American Heart Association's Scientific Sessions 2014. Elevated blood pressure is a major risk factor for the development of heart and blood vessel disease. It is known that following U.S. dietary guidelines can decrease the risk for heart and blood vessel disease, their effects on specific blood pressure measurements were unclear. In this study, researchers found that blood pressure measurements were higher among study participants who did not follow ...

Social media strategy may increase public awareness about donor heart needs

2014-11-18
Using social media to deliver both emotional and concise medical content as well as the need for heart transplants and organs resulted in a higher engagement with members, according to research presented at the American Heart Association's Scientific Sessions 2014." "Social media has not been used extensively in the healthcare industry, and if we can effectively bridge the gap between health education and medicine using social networks and peer influence, we can potentially have many beneficial applications to the healthcare system," said Mohammad Soroya, lead author ...

Youths with a family history of substance use disorders have less efficient forebrain

2014-11-18
Youths with a family history of alcohol and other drug use disorders have a greater risk of developing substance-use disorders (SUDs) themselves than their peers with no such family histories. A new study examines forebrain activity in youths with and without a family history of SUDs. Findings indicate that youths with a family history have forebrain regions that function less efficiently. Researchers and clinicians know that youths with a family history of alcohol and other drug use disorders (FH+) have a greater risk of developing substance-use disorders (SUDs) ...

Chronic alcohol intake can damage white matter pathways across the entire brain

2014-11-18
Chronic misuse of alcohol results in measurable damage to the brain. A new study uses high-resolution structural magnetic resonance (MR) scans to compare the brains of individuals with a history of alcoholism versus those of healthy light drinkers. The abstinent alcoholics showed pronounced reductions in frontal and superior white matter tracts. Chronic misuse of alcohol results in measurable damage to the brain. Chronic drinking may be particularly damaging to the integrity of frontal white matter tracts, which can interfere with cognitive and inhibitory control ...

LAST 30 PRESS RELEASES:

Mysterious ‘Dark Dwarfs’ may be hiding at the heart of the Milky Way

Real-world data shows teclistamab can benefit many multiple myeloma patients who would have been ineligible for pivotal trial

Scientists reveal how a key inflammatory molecule triggers esophageal muscle contraction

Duration of heat waves accelerating faster than global warming

New mathematical insights into Lagrangian turbulence

Clinical trials reveal promising alternatives to high-toxicity tuberculosis drug

Artificial solar eclipses in space could shed light on Sun

Probing the cosmic Dark Ages from the far side of the Moon

UK hopes to bolster space weather forecasts with Europe's first solar storm monitor

Can one video change a teen's mindset? New study says yes - but there’s a catch

How lakes connect to groundwater critical for resilience to climate change, research finds

Youngest basaltic lunar meteorite fills nearly one billion-year gap in Moon’s volcanic history

Cal Poly Chemistry professor among three U.S. faculty to be honored for contributions to chemistry instruction

Stoichiometric crystal shows promise in quantum memory

Study sheds light on why some prostate tumors are resistant to treatment

Tree pollen reveals 150,000 years of monsoon history—and a warning for Australia’s northern rainfall

Best skin care ingredients revealed in thorough, national review

MicroRNA is awarded an Impact Factor Ranking for 2024

From COVID to cancer, new at-home test spots disease with startling accuracy

Now accepting submissions: Special Collection on Cognitive Aging

Young adult literature is not as young as it used to be

Can ChatGPT actually “see” red? New results of Google-funded study are nuanced

Turning quantum bottlenecks into breakthroughs

Cancer-fighting herpes virus shown to be an effective treatment for some advanced melanoma

Eliminating invasive rats may restore the flow of nutrients across food chain networks in Seychelles

World’s first: Lithuanian scientists’ discovery may transform OLED technology and explosives detection

Rice researchers develop superstrong, eco-friendly materials from bacteria

Itani studying translation potential of secure & efficient software updates in industrial internet of things architectures

Elucidating the source process of the 2021 south sandwich islands tsunami earthquake

Zhu studying use of big data in verification of route choice models

[Press-News.org] Penn-led team prevents memory problems caused by sleep deprivation