Behaviorally, SRS was characterized in the mice by head nodding, forelimb clonus, rearing and falling.
From the nature.com
Indeed, when his ankle was flexed suddenly, it continued to jerk back and forth on its own three or four times before stopping, a phenomenon known as clonus.
From the well.blogs.nytimes.com
He was confused and agitated, his heart rate, body temperature and blood pressure were elevated, and he was trembling and had clonus, a sign of muscle hyper-reflexiveness.