Trauma is parts (Part 2): Split-brain studies
The "Part One" post on this topic explained that psychological trauma is more a brain injury than a mental illness. Networks of neurons in the mind responsible for defense (fight, flight, etc.) get stuck in trauma time when, during terrible helplessness, they remain unresolved. And if that trauma is chronic in childhood, there can be more than one part, and those parts contain larger, more functional, sections of the mind, resulting in symptoms that cause some clients to think they might be schizophrenic. Please read the first post either before or after this one [click here].
Split brain research: a 5 minute video that helps explain complex trauma (but isn't about trauma)
In some cases of severe epilepsy (seizures), it is necessary to cut the brain down the center to prevent electrical impulses from crossing over. This saves people's lives, and they are for the most part able to live a totally normal life. However, there are some interesting symptoms, and the following video explains classic research into this. If you have been to college and took Psychology 101, you may remember this.
Now, to understand dissociative psychological trauma, think of the "parts" of the brain in the video (left and right) and replace that concept with "parts" of the brain cut apart in trauma (defense systems, childhood attachment systems). They aren't fully sharing information. Someone can fully feel that they do not know something, when part of them knows it very well. In fact, some clients are been able to write down parts of what happened to them, even while verbally stating that they know nothing about it! It's not strange or unexpected, just like split-brain individuals in the video. As I mentioned, trauma is more of a physical injury than a mental illness--football players and veterans with traumatic brain injuries develop symptoms that look like PTSD.
One important point is, in the case of early childhood psychological trauma, there can be an extreme phobia of "parts," even the concept of them. When these parts of the brain that contain more material than just "fight/flight," such as childhood attachment functions and other complex systems (play, eating, caring, etc.), they can get more elaborate than simple emotional parts--elaborate enough to seem like different people acting separately. In this case, childhood trauma is very much like the split brain study, only involving nightmarish, horrifying elements that we'd rather not delve into. Education such as this post on the science of the matter is comforting to clients, as they begin to realize that when they acknowledge the splits in their brain, they become more able to communicate with themselves to tell the story of the trauma and heal it. In most cases with children, if there had been a caring adult to listen to the story, the trauma would have resolved itself. The part of self doing everyday life becomes that adult in therapy, and then the mind starts to weave back together--no more "parts," just one big healthy mind.
Here's one last point, on the topic of the phobia of parts. New research appears to indicate that split-brain individuals do NOT have separate consciousnesses! That means that they are NOT different people [click here for link].
In the same way, traumatized parts of self that act somewhat independently are a physical reality, but the idea of "multiple personalities" is entirely wrong. A chronically traumatized client is ONE personality, fractured and not on the same page with themselves. Therapy is essentially about getting parts of the brain to reconnect, which involves living life in new ways, developing self-compassion, and treating traumatic memories.