As you know, the brain has billions of neurons. They are arranged in complex circuits that allow you to make decisions, control movement, perceive the world, and so on. MIT Neuroscientists have reported that simple mathematical computations underlie these brain circuits. No surprise, deciphering those circuits is critical to understanding how the brain works and what goes wrong in neurological disorders. According to Mriganka Sur, the Paul E. Newton Professor of Neuroscience and senior author of the Nature paper, two major classes of brain cells repress neural activity in specific mathematical ways: One type subtracts from overall activation, while the other divides it. “These are very simple but profound computations,” Sur said. There is growing evidence that alterations in excitation and inhibition are at the core of many subsets of neuropsychiatric disorders. Hopefully, these findings will help scientists learn more about diseases thought to be caused by these imbalances, including autism, bipolar disorder, and schizophrenia.