It weighs a mere 3 pounds, but a single cubic centimeter has as many connections as there are stars in the Milky Way Galaxy. This marvel of complexity is the human brain, and it's the subject of the six-part series "The Brain with David Eagleman," premiering Oct. 14 on PBS.

Eagleman, a noted neuroscientist, New York Times best selling author and Guggenheim Fellow, takes viewers on a fascinating journey inside their heads.

PHOTOS BREAK: 8 natural mysteries that can't be explained

"The show isn't about brain anatomy, strange brain traumas or diseases. It's about your brain and what we can learn from studying normal brains," says Eagleman. "The goal was to make it around these really big questions — What is reality? Who am I? How do I decide? Who's in control? Who will we be? — and tie human stories and neuroscience into everything we talk about. There's a narrative that takes place over each episode and a bigger thread that connects all six. It's me guiding the viewer into their inner cosmos. It's a journey into the brain and what it means to be a human. It’s the story of you, how your brain functions and all of the stories I cover are toward that end."

One of them is about a girl who has epilepsy and had half her brain removed. "If you do that kind of surgery under the age of eight, a child will be totally fine. All of the functions that would have been taken care of with the other hemisphere get mapped onto the remaining hemisphere and the person's just fine. You can't do that in an adult. They'll die. But children's brains are sufficiently plastic," explains Eagleman.

Another story "has to do with a very fascinating study about hundreds of nuns and priests who all agreed to donate their brains upon their deaths. The researchers were really surprised when they discovered that about a third of the brains, when they looked at them under the microscope at autopsy, had the signs of Alzheimer's disease in them. And yet, none of the cognitive symptoms were apparent when the people were alive. Why? It's because the nuns who lived together in these convents keep very cognitively active because they're socializing, they've got tasks, they're doing things, as opposed to many people who retire and sit around and don't do much of anything and then they have cognitive decline. If you keep your brain active, you're making new pathways. You're finding new ways to get from A to B even as parts of the tissue are dropping out."

Eagleman explores "the issue of the social brain and how so much of our circuitry is devoted towards other brains and dealing with other brains" in another episode. "We're extremely wired up to be a social species. It's what holds us together. Empathy is the glue that allows us to step into each other's shoes and I explore this issue to try to understand what it is about things like genocide: What happens at a societal level that allows people to dehumanize other groups, and what it takes to rehumanize," he says.

He traveled to Sarajevo to interview survivors of the genocide there, seeking to understand how our knowledge about the brain maps onto the world we live in and what can be done about it, and how we can structure things at a governmental level, and to try to make a better place given the knowledge we have."

Another theme is control. There is, Eagleman says, "all the stuff that your brain is doing under the hood that you have no access to. When you learn how to ride a bicycle at first, you pay a lot of attention but once you know how to do it you don’t think about it. Almost everything that’s happening in the brain including what you believe and how you act, your personality and your reactions are happening under the hood, inaccessible to your consciousness."

He also covers advances in brain-computer interfaces, including a woman who could not control her limbs until two electrode were implanted in her motor cortex. She can now operate a robotic arm from across the room. Some ideas may not be a farfetched as they seem. Will it be possible to download our consciosmess into a computer? "The speculation is that if you could make a Xerox copy of all the details of your brain and simulate that in the computer, it would be just like you," Eagleman says. Other future-of-the species topics include the search for immortality. "I visited a place in Arizona that freezes people in the hope that they’ll be able to revive them in 100 years."

Eagleman, who runs a research laboratory at Baylor College of Medicine, is involved in several projects that are covered in the series. One of them, the subject of a TED Talk he gave in March, is a vest system that helps the deaf hear by translating special patterns of sound. "This is about the brain figuring out how to unlock the code and what to do with it. It turns audio into patterns of vibration on the torso. The brain will figure out how to interpret that so they can come to hear the world through their torso. Other things we're doing in my lab have to do with real time feedback in brain scanning to help cure addiction to crack cocaine," he says.

Eagleman, who grew up idolizing Carl Sagan, originally wanted to be an astrophysicist. "But in my junior year of college I stumbled upon a magazine article about the brain and then went to the library and checked out every book I could find on the brain," he says. "A friend suggested I become a neuroscientist and get paid to figure out how the brain works."

Now he's written several books of his own, including "Incognito: The Secret Lives of the Brain," "Synesthesia," "Why the Net Matters," the novel "Sum" and the newly released "The Brain: The Story of You," a companion text to the TV series. A 1,000-page textbook on cognitive neuroscience for Oxford University Press will be out this month, and in 2016, "Wired," about brain plasticity, and another book "about creativity and the cognitive software that‘s running in all humans that explains the human invention around us."

But it's the far more vast reach of television that particularly excites him. "Television is wonderful as a medium to tell important stories," says Eagleman, who has plenty of ideas that are under discussion for future neuroscience programming. "The study of the brain matters in everything in our lives, including our social policy and the history of our species. The brain is squarely at the center of everything in our lives — why we love, why we wage war, why we become anxious, why we gain wisdom, how we educate our children, how we can improve our system of justice," he says. "I want people to take away an understanding why all the answers are in the study of the human brain, and inspire the next generation of neuroscientists."

Discover the inner cosmos of your brain
A neuroscientist takes you on a journey inside your head with this fascinating PBS series.