The Deepest Well: Healing the Long-Term Effects of Childhood Trauma and Adversity—A Transformative Guide to Understanding Childhood Trauma and Health

by Nadine Burke Harris

Some of the effects of cortisol are similar to those of adrenaline—it raises blood pressure and blood sugar, inhibits cognition (clear thinking), and destabilizes mood. It also disrupts sleep, which makes a lot of sense if you are living in a forest full of bears—better to be a light sleeper.

Children are compelled to give meaning to what is happening to them.

When there is no clear explanation, they make one up; the intersection of trauma and the developmentally appropriate egocentrism of childhood often leads a little kid to think, I made it happen.

There are two types of neuroplasticity, cellular and synaptic. Synaptic plasticity is a change in the strength of the connection across the junction from one brain cell to the next (the synapse). It’s kind of like changing your voice from a whisper to a shout. Cellular plasticity, however, is a change in the number of brain cells that are talking to each other, the difference between one person shouting and a whole stadium shouting. While synaptic plasticity is lifelong (it’s how an old dog learns new tricks), cellular plasticity happens most rapidly in the first years of life. About 90 percent occurs by the time a child turns six, but the rest of it stretches out until about age twenty-five.

Our experiences, both positive and harmful, determine which brain pathways are activated and continue to strengthen over time. In that sense, early experiences literally shape the brain.