Missing Brain Enzyme Causes Abnormal Fear Levels

A neuroscience study being conducted at USC has led researchers to connect abnormal levels of fear in mice models with a missing brain protein. Small amounts of learned fear are not only normal, they are actually healthy. Fear makes us cognizant of our important decisions, and keeps animals and humans from making unnecessarily risky choices. But there are cases of severe and unwarranted fear that perseveres even when there’s nothing to worry about. And a neuroscience and molecular biology study from the University of Southern California is now connecting instances of abnormal fear in mice models with missing brain enzymes MAO A and MAO B. Like humans, the MAO A and B enzymes sit side by side in mice. In the past, researchers have discovered that deficiencies in these enzymes cause developmental disabilities, including autism. The new studies on animal models also show that mice without the proteins all showed abnormal fear levels. In comparison to their litter mates, the mice missing their MAO A and B enzymes learned fear the way the rest did, but their fear responses continued long after they were no longer necessary. And while the rest of the mice would explore and discover things, the enzyme-free mice carried their phobic behavior into all areas of their life, even after the initial experiment was over. Their fear responses spilled over into every area of their life, and became a debilitating condition. With further study, the neurologic discovery could lead to new advancements in the treatments of fear and panic disorders in humans, as well as new ways to study autism origins.