And remember, we keep our supraesophogeal ganglion... to ourselves.

And it corresponds to a little cyst that is located below.

But what is unusual is what the cyst has formed around.

The stegosaurus has a massive cluster of nerves above the rump, the sacral ganglion.

Well it turns out it's these neuromodulators, just like the neuromodulators in that little tiny ganglion in the crabs.

So I really think that, as we learn more, it's going to turn out that the whole fly brain is just like a large version of this stomatogastric ganglion, and that's one of the reasons why it can do so much with so few neurons.

The photoreceptor cells are shown here at the top, and then the signals that are detected by the photoreceptors are transformed by various computations until finally that layer of cells at the bottom, the ganglion cells, relay the information to the brain, where we see that as perception.

The amazing thing about this is that it's controlled by a really tiny set of neurons, about two dozen neurons that can produce a vast variety of different motor patterns, and the reason it can do this is that this little tiny ganglion in the crab is actually inundated by many, many neuromodulators.