In this week’s Medical Discovery News with UTMB’s David Niesel and Norbert Herzog: Research shows chronic stress leads to mood disorders such as depression, which has enormous effects on the brain. It changes brain cell behavior and the structure of brain tissues. For example, the hippocampus, which is the brain’s memory center, can shrink in people with a history of depression. And neurons, which are cells that transmit brain signals, can slow down.