Building and burying fear memories in the brain

The world is a dangerous place. Whether this danger takes the form of an automobile careening toward you or a verbal threat from a stranger, your brain is highly adapted to perceive such threats, organize appropriate defensive behaviors, and record the circumstances surrounding the experience. Indeed, memories of fearful events serve a critical biological function by allowing humans and other animals to anticipate future dangers. But these memories can also feed pathological fear, yielding crippling clinical conditions such as panic disorder. In this review, the author will examine how the brain builds fear memories and how these memories come to be suppressed when they no longer predict danger. The review will focus on the fundamental role for synapses in the amygdala in acquiring fear memories and the function of neural circuits interconnecting the amygdala, hippocampus, and prefrontal cortex in modulating the expression of such memories once learned. The discovery of the neural architecture for fear memory highlights the powerful interplay between animal and human research and the promise for understanding the neurobiological mechanisms of other complex cognitive phenomena.