THE ALLEN BRAIN ATLAS
Finally, there is a third way to map the brain. Instead of analyzing the brain by using computer simulations or by identifying all the neural pathways, yet another approach was taken with a generous grant of $100 million from Microsoft billionaire Paul Allen. The goal was to construct a map or atlas of the mouse brain, with the emphasis on identifying the genes responsible for creating the brain.
It is hoped that this understanding of how genes are expressed in the brain will help in understanding autism, Parkinson’s, Alzheimer’s, and other disabilities. Since a large number of mouse genes are found in humans, it’s possible that findings here will give us insight into the human brain.
With this sudden infusion of funds, the project was completed in 2006, and its results are freely available on the web. A follow-up project, the Allen Human Brain Atlas, was announced soon afterward, with the hope of creating an anatomically and genetically complete 3-D map of the human brain. In 2011, the Allen Institute announced that it had mapped the biochemistry of two human brains, finding one thousand anatomical sites with one hundred million data points detailing how genes are expressed in the underlying biochemistry. The study confirmed that 82 percent of our genes are expressed in the brain.
“Until now, a definitive map of the human brain, at this level of detail, simply hasn’t existed,” says Dr. Allen Jones of the Allen Institute. “The Allen Human Brain Atlas provides never-before-seen views into our most complex and most important organ,” he adds.
OBJECTIONS TO REVERSE ENGINEERING
Scientists who have dedicated their lives to reverse engineering the brain realize that decades of hard work lie ahead of them. But they are also convinced of the practical implications of their work. They feel that even partial results will help decode the mystery of mental diseases that have afflicted humans throughout our history.
The cynics, however, may claim that, after this arduous task is finished, we will have a mountain of data with no understanding of how it all fits together. For example, imagine a Neanderthal who one day comes across the complete blueprint for an IBM Blue Gene computer. All the details are there in the blueprint, down to the very last transistor. The blueprint is huge, taking up thousands of square feet of paper. The Neanderthal may be dimly aware that this blueprint is the secret of a super-powerful machine, but the sheer mass of technical data means nothing to him.
Similarly, the fear is that, after spending billions deciphering the location of every neuron of the brain, we won’t be able to understand what it all means. It may take many more decades of hard work to see how the whole thing functions.
For example, the Human Genome Project was a smashing success in sequencing all the genes that make up the human genome, but it was a huge disappointment for those who expected immediate cures for genetic diseases. The Human Genome Project was like a gigantic dictionary, with twenty-three thousand entries but no definitions. Page after page of this dictionary is blank, yet the spelling of each gene is perfect. The project was a breakthrough, but at the same time it’s just the first step in a long journey to figure out what these genes do and how they interact.
Similarly, just having a complete map of every single neural connection in the brain does not guarantee that we will know what these neurons are doing and how they react. Reverse engineering is the easy part; after that, the hard part begins—making sense of all this data.
THE FUTURE
But assume for now that the moment has finally arrived. With much fanfare, scientists solemnly announce that they have successfully reverse engineered the entire human brain.
Then what?
One immediate application is to find the origins of certain mental diseases. It’s thought that many mental diseases are not caused by the massive destruction of neurons, but by a simple misconnection. Think of genetic diseases that are caused by a single mutation, like Huntington’s disease, Tay-Sachs, or cystic fibrosis. Out of three billion base pairs, a single misspelling (or repetition) can cause uncontrollable flailing of your limbs and convulsions, as in Huntington’s disease. Even if the genome is 99.9999999 percent accurate, a tiny flaw might invalidate the entire sequence. That is why gene therapy has targeted these single mutations as possible genetic diseases that can be fixed.
Likewise, once the brain is reverse engineered, it might be possible to run simulations of the brain, deliberately disrupting a few connections to see if you can induce certain illnesses. Only a handful of neurons may be responsible for major disruptions of our cognition. Locating this tiny collection of misfiring neurons may be one of the jobs of the reverse-engineered brain.
One example might be Capgras delusion, in which you see someone you recognize as your mother, but you believe that person to be an impostor. According to Dr. V. S. Ramachandran, this rare disease might be due to a misconnection between two parts of the brain. The fusiform gyrus in the temporal lobe is responsible for recognizing the face of your mother, but the amygdala is responsible for your emotional response in seeing your mother. When the connection between these two centers is disrupted, an individual can recognize his mother’s face perfectly well, but, since there is no emotional response, he is also convinced that she is an impostor.
Another use for the reverse-engineered brain is to pinpoint precisely which cluster of neurons is misfiring. Deep brain stimulation, as we’ve seen, involves using tiny probes to dampen the activity of a tiny portion of the brain, such as Broadmann’s area 25, in the case of certain severe forms of depression. Using the reverse-engineered map, it might be possible to find precisely where the neurons are misfiring, which may involve only a handful of neurons.
A reversed-engineered brain would also be of great help to AI. Vision and face recognition are done effortlessly by the brain, but they still elude our most advanced computers. For example, computers can recognize with 95 percent or greater accuracy human faces that look straight ahead and are part of a small data bank, but if you show the computer the same face from different angles or a face that’s not in the database, the computer will most likely fail. Within .1 seconds, we can recognize familiar faces from different angles; it’s so easy for our brains that we are not even aware we are doing it. Reverse engineering the brain may reveal the mystery of how this is done.
More complicated would be diseases that involve multiple failures of the brain, such as schizophrenia. This disorder involves several genes, plus interactions with the environment, which in turn cause unusual activity in several areas of the brain. But even there, a reverse-engineered brain would be able to tell precisely how certain symptoms (such as hallucinations) are formed, and this might pave the way for a possible cure.
A reverse-engineered brain would also solve such basic but unresolved questions as how long-term memories are stored. It is known that certain parts of the brain, such as the hippocampus and amygdala, store memories, but how the memory is dispersed through various cortices and then reassembled to create a memory is still unclear.
Once the reverse-engineered brain is fully functional, then it will be time to turn on all its circuits to see if it can respond like a human (i.e., to see if it can pass the Turing test). Since long-term memory is already encoded in the neurons of the reverse-engineered brain, it should be obvious very quickly whether the brain can respond in a way indistinguishable from a human.
Finally, there is one impact of reverse engineering the brain that is rarely discussed but is on many people’s minds: immortality. If consciousness can be transferred into a computer, does that mean we don’t have to die?
Speculation is never a waste of time. It clears away the deadwood in the thickets of deduction.
—ELIZABETH PETERS
We are a scientific civilization.… That means a civilization in which knowledge and its integrity are crucial. Science is only a Latin word for knowledge.… Knowledge is our destiny.
—JACOB BRONOWSKI
12 THE FUTURE MIND BEYOND MATTER
Can consc
iousness exist by itself, free from the constraints of the physical body? Can we leave our mortal body and, like spirits, wander around this playground called the universe? This was explored on Star Trek, when Captain Kirk of the starship Enterprise encounters a superhuman race, almost a million years more advanced than the Federation of Planets. They are so advanced that they have long since abandoned their frail, mortal bodies, and now inhabit pulsating globes of pure energy. It has been millennia since they could feel intoxicating sensations, such as breathing fresh air, touching another’s hand, or feeling physical love. Their leader, Sargon, welcomes the Enterprise to their planet. Captain Kirk accepts the invitation, acutely aware that this civilization could instantly vaporize the Enterprise if it wanted to.
But unknown to the crew, these super beings have a fatal weakness. For all their advanced technology, they have been severed for hundreds of thousands of years from their physical bodies. As such, they yearn to feel the rush of physical sensations and long to become human again.
One of these super beings, in fact, is evil and determined to gain possession of the physical bodies of the crew. He wants to live like a human, even if it means destroying the mind of the body’s owner. Soon a battle breaks out on the deck of the Enterprise, as the evil entity seizes control of Spock’s body and the crew fights back.
Scientists have asked themselves, Is there a law of physics preventing the mind from existing without the body? In particular, if the conscious human mind is a device that constantly creates models of the world and simulates them into the future, is it possible to create a machine that can simulate this entire process?
Previously, we mentioned the possibility of having our bodies placed in pods, as in the movie Surrogates, while we mentally control a robot. The problem here is that our natural body will still gradually wither away, even if our robot surrogate keeps on going. Serious scientists are contemplating whether we can actually transfer our minds into a robot so we can become truly immortal. And who wouldn’t want a chance at eternal life? As Woody Allen once said, “I don’t want to live forever through my works. I want to live forever by not dying.”
Actually, millions of people already claim that it is possible for the mind to leave the body. In fact, many insist that they have done it themselves.
OUT-OF-BODY EXPERIENCES
The idea of minds without bodies is perhaps the oldest of our superstitions, embedded deep within our myths, folklore, dreams, and perhaps even our genes. Every society, it seems, has some tale of ghosts and demons who can enter and leave the body at will.
Sadly, many innocents were persecuted to exorcize the demons that were supposedly possessing their bodies. They probably suffered from mental illness, such as schizophrenia, in which victims are often haunted by voices generated by their own minds. Historians believe that one of the Salem witches who was hung in 1692 for being possessed probably had a rare genetic condition, called Huntington’s disease, that causes uncontrolled flailing of the limbs.
Today some people claim that they have entered a trancelike state in which their consciousness has left their body and is free to roam throughout space, even able to look back at their mortal body. In a poll of thirteen thousand Europeans, 5.8 percent claimed they had had an out-of-body experience. Interviews with people in the United States show similar numbers.
Nobel laureate Richard Feynman, always curious about new phenomena, once placed himself in a sensory deprivation tank and tried to leave his physical body. He was successful. He would later write that he felt that he had left his body, drifted into space, and saw his motionless body when he looked back. However, Feynman later concluded that this was probably just his imagination, caused by sensory deprivation.
Neurologists who have studied this phenomenon have a more prosaic explanation. Dr. Olaf Blanke and his colleagues in Switzerland may have located the precise place in the brain that generates out-of-body experiences. One of his patients was a forty-three-year-old woman who suffered from debilitating seizures that came from her right temporal lobe. A grid of about one hundred electrodes was placed over her brain in order to locate the region responsible for her seizures. When the electrodes stimulated the area between the parietal and temporal lobes, she immediately had the sensation of leaving her body. “I see myself lying in bed, from above, but I only see my legs and lower trunk!” she exclaimed. She felt she was floating six feet above her body.
When the electrodes were turned off, however, the out-of-body sensation disappeared immediately. In fact, Dr. Blanke found that he could turn the out-of-body sensation on and off, like a light switch, by repeatedly stimulating this area of the brain. As we saw in Chapter 9, temporal lobe epileptic lesions can induce the feeling that there are evil spirits behind every misfortune, so the concept of spirits leaving the body is perhaps part of our neural makeup. (This may also explain the presence of supernatural beings. When Dr. Blanke analyzed a twenty-two-year-old woman who was suffering from intractable seizures, he found that, by stimulating the temporoparietal area of the brain, he could induce the sensation that there was a shadowy presence behind her. She could describe this person, who even grabbed her arms, in detail. His position would change with each appearance, but he would always appear behind her.)
Human consciousness, I believe, is the process of continually forming a model of the world, in order to simulate the future and carry out a goal. In particular, the brain is receiving sensations from the eyes and inner ear to create a model of where we are in space. However, when the signals from our eyes and ears are in contradiction, we become confused about our location. We often get nauseous and throw up. For example, many people develop sea sickness when they are on a rocking boat because their eyes, looking at the cabin walls, tell them that they are stationary, but their inner ear tells them that they are swaying. The mismatch between these signals causes them to become nauseous. The remedy is to look out at the horizon so that the visual image matches the signals from the inner ear. (This same sense of nausea can be induced even if you are stationary. If you look at a spinning garbage can with bright vertical stripes painted on it, the stripes seem to move horizontally across your eyes, giving you the sensation that you are moving. But your inner ear says you are stationary. The resulting mismatch causes you to throw up after a few minutes, even if you are sitting in a chair.)
The messages from the eyes and inner ear can also be disrupted electrically, at the boundary of the temporal and parietal lobes, and this is the origin of out-of-body experiences. When this sensitive area is touched, the brain gets confused about where it is located in space. (Notably, temporary loss of blood or oxygen or excess carbon dioxide in the blood can also cause a disruption in the temporoparietal region and induce out-of-body experiences, which may explain the prevalence of these sensations during accidents, emergencies, heart attacks, etc.)
NEAR-DEATH EXPERIENCES
But perhaps the most dramatic category of out-of-body experiences are the near-death stories of individuals who have been declared dead but then mysteriously regained consciousness. In fact, 6 to 12 percent of survivors of cardiac arrest report having near-death experiences. It’s as though they have cheated death itself. When interviewed, they have dramatic tales of the same experience: they left their body and drifted toward a bright light at the end of a long tunnel.
The media have seized upon this, with numerous best sellers and TV documentaries devoted to these theatrical stories. Many bizarre theories have been proposed to explain near-death experiences. In a poll of two thousand people, fully 42 percent believed that near-death experiences were proof of contact with the spiritual world that lies beyond death. (Some believe that the body releases endorphins—natural narcotics—before death. This may explain the euphoria that people feel, but not the tunnel and the bright lights.) Carl Sagan even speculated that near-death experiences were a reliving of the trauma of birth. The fact that these individuals recount very similar experiences doesn’t necessarily corroborate their glimpses
into the afterlife; in fact, it seems to indicate that there is some deep neurological event happening.
Neurologists have looked into this phenomenon seriously and suspect that the key may be the decrease of blood flow to the brain that often accompanies near-death cases, and which also occurs in fainting. Dr. Thomas Lempert, a neurologist at the Castle Park Clinic in Berlin, conducted a series of experiments on forty-two healthy individuals, causing them to faint under controlled laboratory conditions. Sixty percent of them had visual hallucinations (e.g., bright lights and colored patches). Forty-seven percent of them felt that they were entering another world. Twenty percent claimed to have encountered a supernatural being. Seventeen percent saw a bright light. Eight percent saw a tunnel. So fainting can mimic all the sensations people have in near-death experiences. But precisely how does this happen?
The mystery of how fainting can simulate near-death experiences may be solved by analyzing the experiences of military pilots. The U.S. Air Force, for example, contacted neurophysiologist Dr. Edward Lambert to analyze military pilots who blacked out when experiencing high g forces (i.e., when executing a tight turn in a jet or pulling out of a dive). Dr. Lampert placed pilots in an ultracentrifuge at the Mayo Clinic in Rochester, Minnesota, which spun them around in a circle until they experienced high g forces. As blood drained from their brain, they would become unconscious after fifteen seconds of experiencing several g’s of acceleration.
He found that after only five seconds, the blood flow to the pilots’ eyes diminished, so that their peripheral vision dimmed, creating the image of a long tunnel. This could explain the tunnel that is often seen by people having a near-death experience. If the periphery of your vision blacks out, all you see is the narrow tunnel in front of you. But because Dr. Lampert could carefully adjust the velocity of the centrifuge by turning a dial, he found he could keep the pilots in this state indefinitely, allowing him to prove that this tunnel vision is caused by loss of blood flow to the periphery of the eye.