科学美国人60秒:Childhood Stress Decreases Size of Brain Regions

Children who experience neglect, abuse and poverty have a tougher time as adults than do well-cared-for kids. Now there’s evidence that such stress can actually change the size of brain structures responsible for learning, memory and processing emotion. The finding is in the journal Biological Psychiatry. [Jamie L. Hanson et al, Behavioral Problems After Early Life Stress: Contributions of the Hippocampus and Amygdala]

Researchers took images of the brains of 12-year-olds who had suffered either physical abuse or neglect or had grown up poor. From the images the scientists were able to measure the size of the amygdala and hippocampus—two structures involved in emotional processing and memory. And they compared the sizes of these structures with those of 12-year-old children who were raised in middle-class families and had not been abused. And they found that the stressed children had significantly smaller amygdalas and hippocampuses than did the kids from the more nurturing environments.

Early stress has been associated with depression, anxiety, cancer and lack of career success later on in adulthood. This study on the sizes of brain regions may offer physiological clues to why what happens to toddlers can have such a profound impact decades later.

—Christie Nicholson