The Hippocampus

Seahorse exhibit at the Georgia Aquarium



I love it when I read a book that makes me want to know more. Such was the case when I read The Year of Fog by Michelle Richmond. The story revolves around a woman whose young daughter disappears while the two are spending the afternoon on a foggy beach. She struggles to recall any detail that might help her find her missing daughter, who she believes is still alive.

The book touches on several concepts regarding memory, memory recall and the brain. I found these theories and facts fascinating and was particularly drawn to Richmond’s description of the hippocampus:  a seahorse-shaped portion of the brain responsible for memory and emotion. I immediately looked this up on the internet and found even more intriguing information about the hippocampus.

The hippocampus is the part of the brain involved in memory forming, organizing, and storing. It forms new memories and connects them to emotions and senses, which explains why certain smells and sounds trigger strong emotional memories. The hippocampus indexes memories, sending them to the appropriate part of the cerebral hemisphere for long-term storage and retrieval. It is also essential for creating new memories. As one site explained it, if you didn't have a hippocampus, you couldn't live in the present; you'd be stuck in the past of old memories. Which sparked a lightbulb moment in me: the hippocampus’ function must be related to Alzheimer’s.

It is. Alzheimer's disease severely affects the hippocampus first, before other parts of the brain.  So memory is usually the first thing to start to falter in Alzheimer's. A person without a properly functioning hippocampus lacks the ability to make new memories.  That is why someone with Alzheimer’s can’t recall recent visitors or phone calls. They can’t remember current conversations. They simply don’t have the ability to do so.

I found this insight absolutely frightening. Nothing scares me more than the idea of losing my memory. While there is some research into neurogenesis, or the birth of brand new brain cells in the hippocampus and frontal lobes, I couldn’t get past the image of that critical seahorse-shaped portion of my brain shriveling and shrinking. If only I knew how to prevent it from happening. I read that there is a connection between estrogen levels and the hippocampus; I want to delve deeper into that.

Basically, I want to find out what I can do to keep my little seahorse fully functioning.  And, while my seahorse is still working, I want to write a thank you note to Michelle Richmond for introducing me to my hippocampus in the first place.