Research by a team at the University of California in Berkeley (including noted stress researcher Robert Sapolsky) published research in Molecular Psychiatry that finds chronic stress causes a decrease in neuron cell production and an increase in glial (connecting) cell production in the hippocampi of adult rats. The research has implications for how early stress causes changes that may show up as anxiety and mood disorders, according to the lead researcher.
Chetty, S., Friedman, A., Taravosh,-Lahn, K., Kirby, E., et al; Stress and glucocorticoids promote oligodendrogenesis in the adult hippocampus. Molecular Psychiatry. Online February 11, 2014. doi:10.1038/mp.2013.190
“You can imagine that if your amygdala and hippocampus are better connected, that could mean that your fear responses are much quicker, which is something you see in stress survivors,” she said. “On the other hand, if your connections are not so good to the prefrontal cortex, your ability to shut down responses is impaired. So, when you are in a stressful situation, the inhibitory pathways from the prefrontal cortex telling you not to get stressed don’t work as well as the amygdala shouting to the hippocampus, ‘This is terrible!’ You have a much bigger response than you should.” –