Anxiety is the sum of its parts

摘要

We all know anxiety. We might have experienced it while waiting to hear about a promotion at work, or on our way to see the doctor because she wants to talk about test results in person. A diffuse uneasiness, sometimes accompanied by perspiration and subtle changes in breathing, anxiety ebbs and flows depending on life's circumstances, and can even occur for no apparent reason. The condition can be healthy and adaptive, but research in the United States1 shows that, for roughly one-third of people, anxiety is a debilitating disorder at some point in their lives. Nevertheless, answers to important questions - such as how different neuronal populations represent anxiety, and how the various components of the anxious state are constructed and represented in neural circuits - remain elusive. In two studies in this issue, Jennings et al. (page 224) and Kim et al.(page 219) address these questions using optogenetics to manipulate distinct neuronal subpopulations in mice and so dissect out the contribution of intermixed but functionally distinct cell groups.