This Week on NeuroScientistNews: 28 September – 2 October
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Genetic links to seasonal rhythms; drug treatment for depression; Alzheimer's disease and the immune system, and more.
♦ Genetic links to the seasonal clock
Over the past decade, the role of rhythms—whether daily or seasonal—in disease has received a tremendous amount of attention in research and clinical applications. There is growing interest in how rhythms govern our sleep-wake cycles, metabolism and food consumption, along with our mood. Recent efforts to discover the genetics underlying natural variation in these physiological and behavioral processes may uncover how altered or disrupted rhythms may contribute to psychiatric disorders and other diseases. One such disorder, seasonal affective disorder (SAD), is characterized by seasonal mood changes which is typically seen as autumn or winter depression that spontaneously remits during spring and summer.
♦ Two-drug combo helps older adults with hard-to-treat depression
More than half of older adults with clinical depression don't get better when treated with an antidepressant. But results from a multicenter clinical trial that included Washington University School of Medicine in St. Louis indicates that adding a second drug -- an antipsychotic medication -- to the treatment regimen helps many of those patients. The findings, from a study of 468 people over age 60 and diagnosed with depression, are published in The Lancet. The study was sponsored by the National Institute of Mental Health and is the largest of its kind ever undertaken in older people with depression.
♦ The neural mechanism of size constancy clarified
A group of researchers at Osaka University found that neurons in the monkey visual cortical area V4*1, one of the areas in the visual cortex, calculate the size of an object based on information on its retinal image size and the distance from the object. The neural mechanism for the perceptual phenomenon in which size was perceived to be stable even if the distance from the object changed (known as size constancy) was unknown. Many neurons in the visual cortex change their activity according to the size of visual stimulus. It was believed that neurons responded to the size of the image formed on the eye (retinal image); however, size constancy cannot be achieved by such cells alone.
♦ Connecting Alzheimer's disease and the immune system
The role of the immune system in Alzheimer's disease is a hot topic, but exactly how the two are connected and what interventions could help lower risk remain a mystery. In a new study published in Nature Neuroscience, researchers in the Ann Romney Center for Neurologic Diseases at Brigham and Women's Hospital (BWH) investigate how genetic risk factors for Alzheimer's disease may influence a key type of immune cell. Their results lay the groundwork for designing better therapeutic strategies and better prediction tools for risk of developing Alzheimer's disease.
♦ Meningitis model shows infection’s sci-fi-worthy creep into the brain
Scientists at Duke Medicine are using transparent zebrafish to watch in real time as Cryptococcal meningitis takes over the brain. The resulting images are worthy of a sci-fi movie teaser, but could be valuable in disrupting the real, crippling brain infection that kills more than 600,000 people worldwide each year.
