【2017年整理】科学家在大脑中发现新睡眠节点.docx

A sleep-promoting circuit located deep in the primitive1 brainstem has revealed how we fall into deep sleep. Discovered by researchers at Harvard School of Medicine and the University at Buffalo2 School of Medicine and Biomedical Sciences, this is only the second sleep node identified in the mammalian brain whose activity appears to be both necessary and sufficient to produce deep sleep. Published online in August in Nature Neuroscience, the study demonstrates that fully3 half of all of the brains sleep-promoting activity originates from the parafacial zone (PZ) in the brainstem. The brainstem is a primordial4 part of the brain that regulates basic functions necessary for survival, such as breathing, blood pressure, heart rate and body temperature. The close association of a sleep center with other regions that are critical for life highlights the evolutionary5 importance of sleep in the brain, says Caroline E. Bass6, assistant professor of Pharmacology and Toxicology in the UB School of Medicine and Biomedical Sciences and a co-author on the paper. The researchers found that a specific type of neuron in the PZ that makes the neurotransmitter gamma-aminobutyric acid (GABA) is responsible for deep sleep. They used a set of innovative7 tools to precisely8 control these neurons remotely, in essence giving them the ability to turn the neurons on and off at will. These new molecular9 approaches allow unprecedented10 control over brain function at the cellular11 level, says Christelle Ancelet, postdoctoral fellow at Harvard School of Medicine. Before these tools were developed, we often used electrical stimulation12 to activate13 a region, but the problem is that doing so stimulates14 everything the electrode touches and even surrounding areas it didnt. It was a sledgehammer approach, when what we needed was a scalpel. To get the precision required for these experiments, we introduced a virus into the PZ that expressed a designer receptor on GABA neurons only but