One of the best-studied areas in the brain and body’s stress response system is called the hypothalamic-pituitary-adrenal axis. The first two organs of the brain are directly responsible for releasing the adrenaline hormone into the blood. In the HPA system, the perception of a threat triggers the body’s release of stress hormones that end up acting on receptors in the brain. Stress hormones known as glucocorticoids trigger the amygdala, the brain’s threat-detecting center, into high alert so it can tell the body to fight or flee. But this is far from an optimal brain state for learning. Short-term, stimulating the amygdala into a fight-or-flight response also entails shutting down other brain systems, including those responsible for learning and memory. Long-term, stress hormones can do permanent damage to those systems.
Some researchers believe that childhood stress might lead to learning problems in other ways as well. When the brain attempts to cope with stress, it raises the levels of dopamine, one of the brain’s own natural chemicals for transmitting signals between cells that also imparts a feeling of satisfaction and well-being. But high dopamine levels interfere with the proper function of the prefrontal cortex. This area in the very upper front of the brain is responsible for many of the kinds of behavior children are supposed to be in the process of trying to learn planning, organizing, focusing, and tuning out distractions. Not coincidentally, perhaps, many researchers believe Attention Deficit-Hyperactivity Disorder (ADHD) is linked to an imbalance in the brain’s dopamine system. Therefore, chronic stress early in life might lead, or at least contribute, or the development of a learning of a learning disability.
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