This episode dives into the intricacies of muscle twitches and their accompanying electrical activity through the lens of Derek Denny-Brown’s classic paper, “Fibrillation and Fasciculation in Voluntary Muscle." Published in 1938, this landmark study showcased the innovative use of electromyography to distinguish between various types of muscle contractions. Denny-Brown meticulously categorized “true fibrillation” from “false fibrillation”, providing crucial insights into the nature of these involuntary muscle movements. We’ll explore the distinctions between these categories, along with Denny-Brown’s observations on “fasciculations” and their implications for understanding abnormal motor neuron activity. Join us for a deep dive into the groundbreaking work of Derek Denny-Brown and the impact it has had on our understanding of muscle physiology.