AP Photo

When it comes to brains, size really doesn’t matter too much. That one-and-a-half-kilogram lump of electrochemical jelly inside your skull contains approximately 90 billion neurons, or nerve cells, and is roughly a thousand times larger than that of the mouse, which contains about 100 million neurons. It’s the way these neurons are organised, rather than the number of cells or total size, that seems to be more important; more specifically, it’s the way that neurons are connected to each other.