Dr. Erin Bigler: So what I’m going to do now is I’m going to remove the temporal lobe from the insular cortex and just inside the insular cortex are the basal ganglia.
Gordon Johnson: Now these are the insular cortex are these two areas we talked about earlier.
Dr. Erin Bigler: That’s correct.
Gordon Johnson: And insular for inside?
Dr. Erin Bigler: Well or insulated.
Gordon Johnson: Okay.
Dr. Erin Bigler: So I’m going to pull this out here –
Gordon Johnson: You get extra points if you can put this all back together when you’re done.
Dr. Erin Bigler: Which I can. So now we’re looking at the temporal lobes from the bottom. And I’m going to flip it around here and we’ll see a very important structure of the brain and it is shown in green. And that is the hippocampus. So the hippocampus is this structure right here and notice where it is, it’s in the medial part or the inner part of the temporal lobe, and notice it’s got a head, it’s kind of wide and then it sort of narrows down and then it starts to project up. At this point, it becomes predominantly white matter and then all white matter and this is what’s referred to as the fornix. And the fornix then projects down to the thalamus that we’ll look at in a minute and then from the thalamus it projects through the rest of the brain.
Gordon Johnson: And see if we can get that a little bit better optically, because the light is a little tricky.
Dr. Erin Bigler: Oh, okay. Is that good?
Gordon Johnson: It’s great. When we look at this, we have a dark green, we have a lime green and we have a red. What’s the dark, darker green? Is the greener part all part of the hippocampus?
Dr. Erin Bigler: Well there is a commissure that goes across the brain that is reflected in this particular model.
Gordon Johnson: Okay.
Dr. Erin Bigler: But the main thing that I want to show is the green structure
Gordon Johnson: And what is the red?
Dr. Erin Bigler: So the red is actually the connection that goes to the amygdala, which is not shown here. The amygdala is just in front. We’re actually going to look at a 3D graphic that will depict that much better.
Gordon Johnson: Okay. And you were telling us about the fornix.
Dr. Erin Bigler: So this shows you the fornix and it’s a structure that then connects the hippocampus with the rest of the brain in terms of the memory network.