(The following is a simplified summary. More detailed information can be found at the Child Trauma Academy.)
There is now solid scientific proof of what's happening in the adolescent brain as it develops from birth. Considering the new research enables parents and other caregivers to better understand child brain development and how that impacts a child's behavior. The new information provides startling new evidence that may run counter to previously held beliefs about a child's brain function and how that affects overall child development.
When a child is born, there are billions of brain cells floating around in grey matter. The human brain is the only body part that is not fully formed at birth, and will continue to develop for more than 20 years. It's the connections of these billions of brain cells that lay the groundwork for adolescent brain development. If a child is nurtured in healthy ways, experiencing a loving, safe, secure world, those connections will involve appropriate hard wiring. If a child experiences fear, alarm or stress, the brain is flooded with fear and stress hormones, which puts a child in a state of panic and survival, hampering normal brain development.
The human brain develops in hierarchal fashion. There are six brain parts that are important to understand when examining child brain development. The first is the brain stem, which is responsible for managing life-sustaining functions such a breathing, body temperature and blood pressure. Next is the mid-brain (diencephalon), which is part of the brain that provides protection. This part is very reactive (sometimes called the reptilian brain), and is responsible for fight, flight, or freeze reactions. It is self-centered and self-serving. Next is the limbic system, which is the emotional "hot seat" of the brain responsible for feelings and emotional reaction. And then there is the cortex (pre-frontal) which is the thinking part of the brain responsible for problem solving.
Located in the limbic system is a part of the brain called the hippocampus. This is where a person's memories and interpretation of memories are stored. Every experience a child has is stored in his or her hippocampus and may be recalled later in life during similar experiences. And, finally, the amygdala is the "sentry" that determines which parts of the brain are in charge.
As the brain is hard wired from the bottom up (from mid-brain to cortex) as a result of healthy experiences, and as the hippocampus stores memories that are primarily within normal healthy ranges, the brain can operate more and more in an ever-maturing cortex that is in charge of the lower areas of the brain. However, if a child experiences feelings of stress, fear, emotional abandonment or trauma, the brain will dump large quantities of stress and fear hormones into his or her system. The hippocampus may then store memories associated with the stressful circumstances leading up to the hormone dump. These states of alarm can "over-wire" the mid-brain, making it denser and more dominant than it should be.
The amygdala works with the hippocampus to determine which part of the brain is in charge. A child's pre-frontal cortex is not fully developed until after age 20, so most of a child's brain activity is in the limbic system, hence the reason why most children usually will react emotionally to situations. Even in adults, the amygdala may eventually get stuck in the limbic system (what author Daniel Goleman calls "an amygdala hijacking"), whereas a person may over-react emotionally due to a flooding of hormones and an out of control amygdala. As the cortex develops, the amygdala will then decide whether more thinking or problem solving may be needed in a situation, rather than an emotional response.
So every experience and every relationship a child has from birth affects brain development and function. From a child's first breath, brain cell connections are being made based on what's being stored in the hippocampus, and how the brain is eventually hard-wired. A child with a brain that has been developed in healthy ways can allow the child the calmness to think and problem solve, while growing in emotional intelliegence.
Special thanks to Diane Wagenhals, Institute for Professional and Educational Development
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