“What underlies being conscious specifically, as opposed to just being awake? We know it’s not just the number of neurons involved. The cerebellum (the so-called ‘little brain’ hanging off the back of the cortex) has about four times as many neurons as the rest of the brain, but seems barely involved in maintaining conscious level. It’s not even the overall level of neural activity – your brain is almost as active during dreamless sleep as it is during conscious wakefulness. Rather, consciousness seems to depend on how different parts of the brain speak to each other, in specific ways.”