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Ward Plunet
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Dopamine's yin-yang personality: It's an upper and a downer

For decades, psychologists have viewed the neurotransmitter dopamine as a double-edged sword: released in the brain as a reward to train us to seek out pleasurable experiences, but also a "drug" the constant pursuit of which leads to addiction. According to a new study from the University of California, Berkeley, that's only one face of dopamine. The flip side is that dopamine is also released in response to unpleasurable experiences, such as touching a hot tea kettle, presumably training the brain to avoid them in the future. The yin-yang nature of dopamine could have implications for treatment of addiction and other mental disorders. In illnesses such as schizophrenia, for example, dopamine levels in different areas of the brain become abnormal, possibly because of an imbalance between the reward and avoidance circuits in the brain. Addiction, too, may result from an imbalance in reactions to pleasure and pain.
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Performance on exercise test predicts risk of death from cardiovascular disease and cancer

Performance on an exercise test predicts the risk of death from cardiovascular disease, cancer, and other causes, reports a study presented today at EuroEcho-Imaging 2018. Good performance on the test equates to climbing three floors of stairs very fast, or four floors fast, without stopping. The findings underline the importance of fitness for longevity. The study included 12,615 participants with known or suspected coronary artery disease. Participants underwent treadmill exercise echocardiography, in which they were asked to walk or run, gradually increasing the intensity, and continue until exhaustion. Watch a video of the technique here. The test also generates images of the heart to check its function. During a median 4.7-year follow-up, there were 1,253 cardiovascular deaths, 670 cancer deaths, and 650 deaths from other causes. After adjusting for age, sex, and other factors that could potentially influence the relationship, each MET (metabolic equivalent) achieved was independently associated with 9%, 9%, and 4% lower risks of cardiovascular death, cancer death, and other causes of death during follow-up. The death rate from cardiovascular disease was nearly three times higher in participants with poor compared to good functional capacity (3.2% versus 1.2%, p<0.001). Non-cardiovascular and non-cancer deaths were also nearly three-fold higher in those with poor compared to good functional capacity (1.7% versus 0.6%, p<0.001). Cancer deaths were almost double in participants with poor compared to good functional capacity (1.5% versus 0.8%, p<0.001).
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Scientists identify 'youth factor' in blood cells that speeds fracture repair

During fracture healing, macrophages are found at the fracture site. But when they're depleted, fractures will not heal effectively. Macrophage populations and characteristics can change with aging. "We show that young macrophage cells produce factors that lead to bone formation, and when introduced in older mice, improves fracture healing," said Gurpreet Baht, Ph.D., assistant professor in orthopedic surgery and a lead author of the study. "While macrophages are known to play a role in repair and regeneration, prior studies do not identify secreted factors responsible for the effect," Alman said. "Here we show that young macrophage cells play a role in the rejuvenation process, and injection of one of the factors produced by the young cells into a fracture in old mice rejuvenates the pace of repair. This suggests a new therapeutic approach to fracture rejuvenation."
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Yes, the Octopus Is Smart as Heck. But Why?

It has eight arms, three hearts — and a plan. Scientists aren’t sure how the cephalopods got to be so intelligent.
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Scientists decode mechanism of remembering—and forgetting

It's a common expression to say that your brain is full. Although the brain doesn't literally fill up, in recent years researchers have discovered that the brain does sometimes push out old memories in order to take up new ones. Now, a team at Scripps Research has shown for the first time the physiological mechanism by which a memory is formed and then subsequently forgotten. The research, which was done in fruit flies, looked at the synaptic changes that occur during learning and forgetting. The investigators found that a single dopamine neuron can drive both the learning and forgetting process. The study was published in Cell Reports. "We believe this system is set up to remove memories that are unimportant and not necessarily supposed to last a long time," says first author Jacob Berry, Ph.D., a postdoctoral associate in the Department of Neuroscience on Scripps Research's Florida campus. "I find it elegant that all of this is done with the same neuron. Our paper highlights exactly how this is achieved."
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Researchers discover neural code that predicts behavior

Scientists at the National Eye Institute (NEI) have found that neurons in the superior colliculus, an ancient midbrain structure found in all vertebrates, are key players in allowing us to detect visual objects and events. This structure doesn't help us recognize what the specific object or event is; instead, it's the part of the brain that decides something is there at all. By comparing brain activity recorded from the right and left superior colliculi at the same time, the researchers were able to predict whether an animal was seeing an event. The findings were published today in the journal Nature Neuroscience.
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Large-scale study finds that the Mediterranean diet is best for your mental health

Admittedly, eating chocolate or ice cream to chase the blues away is so much more enjoyable than healthy alternatives. But a new study published in the journal Molecular Psychiatry says that a diet rich in fish, nuts and vegetables could help lower a person's risk of depression. Specifically, a plant-based diet of fruit, vegetables, grains, fish, nuts and olive oil – but little meat or dairy – appears to have benefits in terms of mood. The paper uses some sobering statistics to stress the mood disorder's prevalence and socioeconomic impact. Depression affects more than 300 million people worldwide, equivalent to 7 percent of all women and 4 percent of men. The World Health Organization estimates that about USD 1 trillion is lost each year because of low productivity caused by depression and anxiety disorders.
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Neuropixels technology ready for release

A transformative technology for detecting and recording neural activity in the brain is now available for researchers to purchase through imec, a leading nanoelectronics research center in Belgium. Neuropixels, a new neural-recording technology that lets scientists simultaneously monitor hundreds of neurons throughout an animal's brain, is now being made available for purchase by the research community. The technology vastly improves upon previous methods of detecting and recording neural activity in the brains of living animals, says Tim Harris, a senior fellow at the Howard Hughes Medical Institute (HHMI)'s Janelia Research Campus and leader of the Neuropixels collaboration. Researchers can now collect "more data – as good as they have ever taken – and it's easier to obtain than before," he says.
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Morphing brain DNA hints at a whole new way to treat Alzheimer’s

Brain cells are reshuffling their own DNA. The finding may explain how Alzheimer’s disease develops and pave the way for new treatments using existing HIV drugs. Most drugs for treating Alzheimer’s disease are designed to clear out clumps of beta-amyloid protein that build up in the brain of people with the condition. But they have had disappointing outcomes in clinical trials so far. While studying the gene responsible for making beta-amyloid – called APP – Jerold Chun at Sanford Burnham Prebys Medical Discovery Institute in California and his colleagues discovered something strange. The gene appeared to be able to reshuffle its DNA, allowing it to take thousands of different forms. The team found about 10 times more variants of the APP gene in brain cells from people with Alzheimer’s disease than without. These different forms were able to produce a range of toxic proteins in addition to beta-amyloid. The finding may explain why Alzheimer’s drugs that specifically target beta-amyloid have had limited success, says Chun. “They may be missing thousands of other toxic products that are a bit different or maybe very different,” he says.

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DNA vaccine reduces both toxic proteins linked to Alzheimer's

A DNA vaccine tested in mice reduces accumulation of both types of toxic proteins associated with Alzheimer's disease, according to research that scientists say may pave the way to a clinical trial. A new study by UT Southwestern's Peter O'Donnell Jr. Brain Institute shows that a vaccine delivered to the skin prompts an immune response that reduces buildup of harmful tau and beta-amyloid—without triggering severe brain swelling that earlier antibody treatments caused in some patients. "This study is the culmination of a decade of research that has repeatedly demonstrated that this vaccine can effectively and safely target in animal models what we think may cause Alzheimer's disease," said Dr. Roger Rosenberg, founding Director of the Alzheimer's Disease Center at UT Southwestern. "I believe we're getting close to testing this therapy in people."
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