Early stress might make brains grow up too fast
“The evolutionary push is for you to pass on your genes…We hypothesize that stress drives a reallocation of developmental resources from development of the full brain to development of limbic structures that are important for reproduction.”
The results showing reduced growth but faster hippocampus maturation appear to support an evolution-based hypothesis that mice—and perhaps people, too—interpret early stress as a cue to adapt brain development to match a world where long-term survival seems unlikely, Bath says.
“In the case of development, the stress may be providing a signal about the hospitability of the environment.”
In other words, rather than invest for the long run in optimally refined systems in the cortex for learning rules and suppressing emotional responses, mice may instead invest in accelerating the maturation of more primal systems, such as the hippocampus, to support short-term priorities, like racing to survive long enough to reproduce at least once.
…stress incurred early in life attenuates neural growth. Now a new study with male mice exposed to stress shows that the hippocampus reaches some developmental milestones early—essentially maturing faster in response to stress.
The findings…may lend some credence to the expression that children facing early adversity have to “grow up too fast.”…certain traits in humans and rodents—such as fear-driven learning and memory, sexual development, and neural connectivity among some brain regions—were accelerated, rather than stunted, after early life stress. Some of these qualities, particularly memory and emotion regulation, involve the hippocampus.
Focus on short-term priorities
What they found…was that the hippocampus appeared to mature significantly faster in the stressed mice during their seven weeks from birth to early adulthood.