Mouse Hippocampal Anatomy

Man, you are serious, if you've followed me all the way down here.  All right then, here's an orientation to the anatomy which lies behind the photographs in the second half of Chapter 7.. 

You already learned about the human hippocampus in Chapter 6, or perhaps by taking the Brain Tour about memory. Here's how it looks in a mouse: 

On the left, you can see a dark stripe which loops around in a zig-zag.  There is a symmetrically matched version on the right.  These are the left and right hippocampi in a mouse.  They seem large, perhaps, compared to the size of the hippocampi in humans, which take up much less space compared to the total human brain volume.  But that's because our cortex is so much larger than a mouse's.  In an animal without much cortex, the hippocampus takes up a much greater percentage of brain space. 

The red circle marks the shape you need to remember in the photos below.  This is the "dentate gyrus" of the hippocampus (Why that name?), which turns out to be a region of very hot action in neurogenesis.  Look for this shape: 

because now we're going to look at the tip of that shape, so that in the photo below it will look more like this:


With that orientation, then, here's a look at neurogenesis in a mouse brain. The arrow tips all point at nuclei of brand new cells


Now perhaps you can see where you are, in the rest of the story about neurogenesis in Chapter 7.  (Use that link to go back).