Hippocampus
The researchers performed a series of experiments on adult rats, focusing on the hippocampus region of the brain (which regulates memory and emotions). During the experiments, they found the neural stem cells behaved differently than expected. Prior to this study, the general belief was that these stem cells would only become neurons or astrocyte cells, a type of glial cell. However, under stress, these cells became another type of glial cells, oligodendrocyte, which are the myelin-producing cells. These cells also help form the synapses, which are the communication tools that allow nerve cells to exchange information.
Thus, chronic stress causes more myelin-producing cells and fewer neurons. This disrupts the balance in the brain, causing communication in the brain cells to lose its normal timing, which could lead to problems.