Prof. Takao Hensch Submitted: Early life experience shapes brain function – from motor skills to language and emotions. We explore the biological basis of these windows of opportunity and vulnerability and how they are derailed in mental illnesses. Integrating molecular, cellular and systems neuroscience, our work has revealed these “critical periods” are themselves plastic and reversible. Specific, inhibitory (GABA) circuits trigger their onset timing, while “brake”-like factors actively prevent circuit rewiring as they close. Translational research inspired by this work targets recovery from neurodevelopmental disorders, such as amblyopia, epilepsy and autism spectrum disorders, as well as the potential for recovery of function later in life.