Discoveries

Neurons often get most of the credit for keeping our brains sharp and functioning—as well as most of the blame when it comes to brain diseases. But star-shaped cells called astrocytes, another abundant cell in the human brain, may bear the brunt of the responsibility for exacerbating the symptoms of some neurodevelopmental disorders. Associate Professor Nicola Allen and colleagues have now identified a molecule produced by astrocytes that interferes with normal neuron development in Rett, fragile X, and Down syndromes.

Assistant Professor Sung Han, co-first authors Sukjae Joshua Kang and Shijia Liu, and colleagues have uncovered a molecular pathway that distills threatening sights, sounds, and smells into a single message: Be afraid. A molecule called CGRP enables neurons in two separate areas of the brain to bundle threatening sensory cues into a unified signal, tag it as negative, and convey it to the amygdala, which translates the signal into fear. The research may lead to new therapies for fear-related disorders such as PTSD or hypersensitivity disorders such as autism, migraines, and fibromyalgia.

The brain mechanisms that cause aggressive behavior have been well studied. Far less understood are the processes that tell the body when it’s time to stop fighting. Associate Professor Kenta Asahina and colleagues have now identified a gene and a group of cells in the brain that play a critical role in suppressing aggression in fruit flies. The findings have implications for disorders such as Parkinson’s disease, which can sometimes cause behavioral changes like increased aggression and combativeness.