When people experience trauma like Ford’s, their brain stem takes control. This knotty structure at the base of the skull is responsible for our survival instincts and autonomic body processes, and is often described as the oldest part of the brain. The brain stem reacts to trauma by sending the body into “fight, freeze or flight” survival mode, where any non-essential functions are shut down. At the same time, the sympathetic nervous system floods the body with stress hormones like norepinephrine, helping the person to get away from, or fight, whatever is causing them trauma. Eventually, things go back to normal—but the event can cause long-lasting changes to deeper structures of the person’s brain. A meta-analysis published in the American Journal of Psychiatry earlier this year examined 66 studies over 31 years, and found that people who suffered from post-traumatic stress disorder had “reduced brain volume, intracranial volume, and volumes of the hippocampus, insula, and anterior cingulate.” (The hippocampus is responsible for memory function, and helps us to distinguish between the present and the past.)

The symptoms are many and various, ranging from cardiorespiratory problems to major depression. But one common result is a complicated relationship with memory. Patients often experience powerful and precise flashbacks of the triggering event itself, while suffering more general memory loss.

At the Kavanaugh hearing, Ford explained her own PTSD, and how it continues to affect what she can and cannot remember about the events of 1982. She’s not simply testifying as a primary witness and victim, but a credible expert witness. Ford is a person who experienced trauma, but she’s also a scientist who knows how that trauma works—and why some memories stick for decades, even while others slide away.

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