Scientists reactivate memory in rats with light
Researchers from University of California-San Diego have found more evidence that strong connections between neurons in the brain are crucial for developing memories. And they were able to deactivate and reactivate fear memories in rats by using a flalshing light. Published in the journal Nature, the findings presented the first scientific evidence that long-term potentiation (LTP), which strengthens connections between neurons, can help form memories.
The scientists used a laser to control specific circuits within rats. When the rats received a shock accompanied by a sound, researchers triggered stimulation by lighting up a group of neurons associated with auditory fear memory. Varying the patterns of that stimulation increased LTP, thus strengthening neuron connections. They were also able to weaken neuron connections through long-term depression (LTD). So when a rat was shocked a second time, they would or wouldn’t be scared of the sound, depending on the strength of the neuron connections.
Therefore, they could end a memory by using LTD and bring a memory back by using LTP. When the rats died, the scientists were able to analyze the brain more closely. They found that the targeted neurons in the experiment exhibited signs of chemical sensitivity. This confirms the connection between the level of neuron strength and memory.
This new information could be used to better understand Alzheimer’s and other memory illnesses, such as post-traumatic stress disorder.
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Sourced from: medicalnewstoday.com, Scientists inactivate and reactivate memories in rats using light
Marijuana may cause sleep problems
The use of marijuana has been linked to a higher risk of sleep problems by new research from the University of Pennsylvania.
Marijuana use is very prevalent, with some reports suggesting that over half of U.S. adults have used it at some point in their life. Now that more and more states are decriminalizing the drug, scientists say it’s more important to study its impact.
For the study, researchers analyzed data from the 2007-2008 National Health and Nutrition Examination Survey. They looked at 1,811 adults aged 20-59 who had reported using cannabis. They collected sleep pattern information, what age the person first tried the drug and the number of times they had used it in the past month.
They found that both current and past marijuana users are significantly more likely to experience sleep problems than non-users. The research found a link between first time marijuana use in adolescence and higher risk for insomnia, but this research did not find a causal relationship between pot smoking and insomnia.
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Sourced from: Medical News Today, Does marijuana use cause sleep problems?
Skin cancer drugs show promising results
Researchers say that two drugs being tested to fight advanced skin cancer are proving to be effective in trials. The findings were released at the American Society of Clinical Oncology conference in Chicago.
The two experimental drugs, called pembrolizumab and nivolumab, block the biological pathway cancers use to disguise themselves from the immune system.
It’s very hard to treat cancer that has spread to other organs, and until a few years ago, the average survival rate was around six months.
In the pembrolizumab trial, researchers looked at 411 patients, and 69 percent of them survived at least a year. This drugs is also being tested against other types of tumors that use the same mechanism to trick the immune system.
The second drug, nivolumab, was tested in combination with existing immunotherapy, ipilimumab. In this trial of 53 patients, 85 percent survived after one year, and 79 percent after two years.
Researchers caution that these are Phase I, early stage trials, and that they’ll have a better idea of the effectiveness of the drugs after much larger Phase III trials in a year.
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Sourced from: BBC, Skin cancer trial results ‘exciting’