Finding and seeing the hippocampus
Here’s Harry. Harry’s looking to your left. His left ear would be right in the middle of this picture. Notice the green portion of the brain: this is called the temporal lobe. It lies right under your temple. Memories of names live in this left temporal lobe: particularly people’s names, names of animals, and names of tools. If you would like two paragraphs on “why these names?”, click here.
The portion of the brain that helps those names get into memory in the first place, this hippocampus thing we are talking about, is also part of this temporal lobe. But you can’t see it here, because it’s an inside fold, not these outside folds you see above. To see the hippocampus, we’ll have to use x-ray vision. Imagine you could just squint and see right through the temporal lobe to what’s underneath. Using some beautiful images from a great medical illustrator, here’s what you’d see:
limbic1_finished
Can you see the temporal lobe, there on the outside, just as before? We’re here to look at the purple part at the bottom: that’s the hippocampus. For the moment you can ignore all the other limbic system elements shown here; we’ll be back to learn more of them in other Tours.
So, there’s that purple thing, part of the innermost fold of the temporal lobe. How “inner” is that? To see that, imagine you could look straight down from the top of Harry’s head, and use your x-ray vision to see the hippocampus, outlined in purple — you could see how far toward the middle it sits:
hiptopcut (1)
Ignore the lines, they’re for the poor medical students who have to memorize all the latin names of the structures shown. You can see it on the left side, outlined; the right one is also shown — see it over there on the right, in shadow a bit? A few more structures have been deleted on the right so you can really see the entire “body” of the hippocampus there, and the “head” with its bulging folds.