Did you know childhood trauma can causes massive changes in the hippocampus, shrinking it so that new, long-term explicit memories cannot form? (The hippocampus is crucial for organizing our short and long term memory.)
Did you know that a traumatized person’s hippocampus is 18% smaller than that of a depressed adult without childhood trauma.
Now here’s an amazing fact: Until very recently doctors and scientists thought that if the brain was broken, you could not fix it. Now we know that as people recover from depression, their memories return, and research suggests that new neurons (or brain cells) are created in the brain stem and hippocampi can grow back!
Brain scientists suspect a stress hormone called “glucocorticoid” kills cells in the hippocampus so it cannot make the synaptic connections in the neural networks that make learning and explicit long-term memory possible (see below for explanation of explicit memory.)
Studies on baby animals taken from their mothers show that a gene turns on the switch for glucocorticoid production. It gets turned on and stays on. Studies on adult survivors of childhood abuse also show signs of glucocorticoid supersensitivity.
We are now begining to understand that depression, high stress, and childhood trauma all release glucocorticoids, which kill hippocampus cells.
The shrunken hippocampus in survivors of trauma is an important discovery. It helps us understand why counselors watch their clients struggle to find explicit memories of their childhood.
So much for the bad news. Now here’s the good news:
1). Antidepressant medications (SSRI’s) increase the number of stem cells that become new neurons in the hippocampus.
2). Counseling helps change the chemical makeup of the brain.
This was a complex subject so let me summarize: Many believe the brain can heal itself. Counseling and Antidepressants can actually cause neurogenesis (new cell growth) in the hippocampus.
*Implicit memory in a two-year old is the kind of memory where we learn some procedure or group of automatic actions where words are not required. They are usually unconscious. Explicit memory, or declarative memory, connects specific facts and events. It begins to develop when a child is almost two years old. It is the type of memory that connects facts and events. It is supported by language)
*Material taken from The Brain That Changes Itself by Norman Doige, M.D.