The hippocampus is part of the brain’s limbic system, the place where emotions are regulated. The hippocampus is believed to be involved in the formation of memories from experienced events…perhaps moving them from the emotionality of the rest of the limbic system into the temporal lobes (where supposedly memories are stored). Brain anatomy and function are much more complex than this, but since none of us have degrees in neurology…or at least I don’t…this oversimplification helps me understand.

Our brains have two hippocampuses (or hippocampi), which I found out recently are named this because they are shaped like sea horses and the genus of seahorse is Hippocampus.

Studies of adults (and now children) who have post-traumatic stress disorder (PTSD) show that their brains have smaller hippocampal volume. So researchers set out to figure out why. They had two theories. First that the trauma itself caused the hippocampus volume to get smaller, or second, that people with smaller hippocampus volumes were more prone to exhibit PTSD.

As they studied this, researchers noted that many times children with PTSD (as measured through salivary cortisol) didn’t seem to have abnormally smaller hippocampi. But as they followed these children and tested them 12-18 months after being diagnosed with PTSD, they found a significant negative correlation between the cortisol levels and hippocampal volume. In other words, if their cortisol levels stayed high their hippocampus volumes decreased.

Studies on twins, though, showed that some people just start out with smaller hippocampi, and that PTSD seems to affect them more severely.

Hmmm…

That’s what is so fascinating about our brains; and so maddening about finding answers for children who have been traumatized. Our brains seem to both have genetic predispositions to being certain ways AND are greatly affected by the environment.

As I read about this study in the blog, Mind Matters, I couldn’t help but think about how many parents of post-institutionalized children I’ve heard wonder why not all babies adopted from the orphanages where severe abuse or neglect was confirmed had the same level of dysfunction as others. Only the combination of genetic predisposition and environment explains this.

I personally think it explains autism and other neurological impairments, too. The answer isn’t either/or…it’s both genetics and environmental toxins that cause autism.

And while I love that someone’s doing the research that needs to be done, as parents we still ask the inevitable question that no one can really answer…”what should we do?” Knowing that our children’s seahorses in their brains were made smaller by their traumatic experiences coupled with their genetics is fascinating, but doesn’t help us “solve” it much, does it?

The bottom line is that trauma damages brains, and complicates lives of children who may already have several other genetic risk factors. Children who come to us through adoption often come from traumatic pasts.

Stopping or lessening the trauma seems to be the variable we (as a society) can change.

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