The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma

by Bessel van der Kolk

Right above the reptilian brain is the limbic system. It’s also known as the mammalian brain, because all animals that live in groups and nurture their young possess one. Development of this part of the brain truly takes off after a baby is born. It is the seat of the emotions, the monitor of danger, the judge of what is pleasurable or scary, the arbiter of what is or is not important for survival purposes. It is also a central command post for coping with the challenges of living within our complex social networks. The limbic system is shaped in response to experience, in partnership with the infant’s own genetic makeup and inborn temperament. (As all parents of more than one child quickly notice, babies differ from birth in the intensity and nature of their reactions to similar events.) Whatever happens to a baby contributes to the emotional and perceptual map of the world that its developing brain creates. As my colleague Bruce Perry explains it, the brain is formed in a “use-dependent manner.”5 This is another way of describing neuroplasticity, the relatively recent discovery that neurons that “fire together, wire together.” When a circuit fires repeatedly, it can become a default setting—the response most likely to occur.