When we slip into sleep and embark on a subconscious journey through our dreams, what exactly is our brain up to? Theoretical physicist, best-selling author, and all around cool guy Michio Kaku returns to Big Think to discuss the science of dreaming, as well as everything Freud got right about our subconscious:

Kaku's most recent best-seller, The Future of the Mind, places its focus on how science explores consciousness. In the interview above, he begins with a discussion of Freud, who Kaku believes may not have been "totally wrong":

"There are many textbooks which simply dismiss Freudian psychology calling it nuts. That is nothing but the sexual fantasies of a repressed [Viennese] scientist of the last century. But now we realize there’s more to it. First of all the unconscious mind. We can actually see the brain in motion and we realize that much of the activity is totally unconscious. Just like what Freud predicted."

Not only was Freud right about unconscious activity, Kaku also mention that neuroscientists utilizing brain scans can identify parts of the brain that correspond with ego, the id, and superego:

"The ego is basically your prefrontal cortex. That is who you are. When you wonder where am I anyway. Well, you’re right there. You are sitting right behind your forehead. And then your desires. We see the pleasure center right there at the center of the brain. That is the libido. We see where the pleasure center is located. And then your conscience is right behind your eyes. The orbital frontal cortex right behind your eyes is where your conscience is. And so we actually see that in motion."

And then, on to dreaming. Like his unique brand of psychology, Freud's work on dreams has been largely dismissed by modern scientists. Kaku notes that brain scans again are able to track the status of your control center while you sleep:

"We realize that it comes at the back of the brain, the very primitive part of the brain and that certain parts of the brain are shut off when you dream. First of all your prefrontal cortex is basically shut off, it’s quiet. Your orbital frontal cortex that is your conscience is also shut off. But that part of the brain is your fact checker. The part of the brain that said, 'Hmmm, that’s not right. Something’s wrong' is right behind your eyes. That’s shut off.

What is active when you dream is your amygdala. Now what does your amygdala govern? Fear and emotions."

So basically, your brain's fact checker rests while its emotional daredevil keeps roaring. Even though your rational brain goes dormant, there are still methods to breaking through the state of analytical paralysis. Experiments at the Max Planck Institute in Germany have revealed that controlling the direction of your dreams -- a phenomenon often called lucid dreaming -- is testable, reproducible, and totally legitimate. The ability to direct one's own dreams (and perhaps the dreams of others à la Inception) could become a major focus of near-future neuroscientific research:

"One day we may be able to brain scan the brain as you dream and put it on a screen. In which case somebody will be able to see you dream and know the direction of the dream and you are conscious of the process."