The Future of the Mind (25 page)

Dr. Michael Sweeney has observed, “
When applied to the prefrontal lobes, TMS has been shown to enhance the speed and agility of cognitive
processing. The TMS bursts are like a localized jolt of caffeine, but nobody knows for sure how the magnets actually do their work.” These experiments hint, but by no means prove, that silencing a part of the left frontotemporal region could initiate some enhanced skills. These skills are a far cry from savant abilities, and we should also be careful to point out that other groups have looked into these experiments, and the results have been inconclusive. More experimental work must be done, so it is still too early to render a final judgment one way or the other.

TMS probes are the easiest and most convenient instrument to use for this purpose, since they can selectively silence various parts of the brain at will without relying on brain damage and traumatic accidents. But it should also be noted that TMS probes are still crude, silencing millions of neurons at a time. Magnetic fields, unlike electrical probes, are not precise but spread out over several centimeters. We know that the left anterior temporal and orbitofrontal cortices are damaged in savants and likely responsible, at least in some part, for their unique abilities, but perhaps the specific area that must be dampened is an even smaller subregion. So each jolt of TMS might inadvertently deactivate some of the areas that need to remain intact in order to produce savantlike skills.

In the future, with TMS probes we might be able to narrow down the region of the brain involved with eliciting savant skills. Once this region is identified, the next step would be to use highly accurate electrical probes, like those used in deep brain stimulation, to dampen these areas even more precisely. Then, with the push of a button, it might be possible to use these probes to silence this tiny portion of the brain in order to bring out savantlike skills.

FORGETTING TO FORGET AND PHOTOGRAPHIC MEMORY

Although savant skills may be initiated by some sort of injury to the left brain (leading to right brain compensation), this still does not explain precisely how the right brain can perform these miraculous feats of memory. By what neural mechanism does photographic memory emerge? The answer to this question may determine whether we can become savants.

Until recently, it was thought that photographic memory was due to the special ability of certain brains to remember. If so, then it might be difficult
for the average person to learn these memory skills, since only exceptional brains are capable of them. But in 2012, a new study showed that precisely the opposite may be true.

The key to photographic memory may not be the ability of remarkable brains to learn; on the contrary, it may be their inability to forget. If this is true, then perhaps photographic memory is not such a mysterious thing after all.

The new study was done by scientists at the Scripps Research Institute in Florida who were working with fruit flies. They found an interesting way in which these fruit flies learn, which may overturn a cherished idea of how memories are formed and forgotten. The fruit flies were exposed to different smells and were given positive reinforcement (with food) or negative reinforcement (with electric shocks).

The scientists knew that the neurotransmitter dopamine was important to forming memories. To their surprise, they found that dopamine actively regulates
both
the formation and the forgetting of new memories. In the process of creating new memories, the dCA1 receptor was activated. By contrast, forgetting was initiated by the activation of the DAMB receptor.

Previously, it was thought that forgetting might be simply the degradation of memories with time, which happens passively by itself. This new study shows that forgetting is an active process, requiring intervention by dopamine.

To prove their point, they showed that by interfering with the action of the dCA1 and DAMB receptors, they could, at will, increase or decrease the ability of fruit flies to remember and forget. A mutation in the dCA1 receptor, for example, impaired the ability of the fruit flies to remember. A mutation in the DAMB receptor decreased their ability to forget.

The researchers speculate that this effect, in turn, may be partially responsible for savants’ skills. Perhaps there is a deficiency in their ability to forget. One of the graduate students involved in the study, Jacob Berry, says, “
Savants have a high capacity for memory. But maybe it isn’t memory that gives them this capacity; maybe they have a bad forgetting mechanism. This might also be the strategy for developing drugs to promote cognition and memory—what about drugs that inhibit forgetting as a cognitive enhancers?”

Assuming that this result holds up in human experiments as well, it could encourage scientists to develop new drugs and neurotransmitters that are
able to dampen the forgetting process. One might thus be able to selectively turn on photographic memories when needed by neutralizing the forgetting process. In this way, we wouldn’t have the continuous overflow of extraneous, useless information, which hinders the thinking of people with savant syndrome.

What is also exciting is the possibility that the BRAIN project, which is being championed by the Obama administration, might be able to identify the specific pathways involved with acquired savant syndrome. Transcranial magnetic fields are still too crude to pin down the handful of neurons that may be involved. But using nanoprobes and the latest in scanning technologies, the BRAIN project might be able to isolate the precise neural pathways that make possible photographic memory and incredible computational, artistic, and musical skills. Billions of research dollars will be channeled into identifying the specific neural pathways involved with mental disease and other afflictions of the brain, and the secret of savant skills may be revealed in the process. Then it might be possible to take normal individuals and make savants out of them. This has happened many times in the past because of random accidents. In the future, this may become a precise medical process. Time will tell.

So far, the methods analyzed here do not alter the nature of the brain or the body. The hope is that through the use of magnetic fields, we will be able to unleash the potential that already exists in our brains but is latent. The philosophy underlying this idea is that we are all savants waiting to happen, and it will just take some slight alteration of our neural circuits to unleash this hidden talent.

Yet another tactic is to directly alter the brain and the genes, using the latest in brain science and also genetics. One promising method is to use stem cells.

STEM CELLS FOR THE BRAIN

It was dogma for many decades that brain cells do not regenerate. It seemed impossible that you could repair old, dying brain cells, or grow new ones to boost your abilities, but all this changed in 1998. That year, it was discovered that adult stem cells could be found in the hippocampus, the olfactory bulb, and the caudate nucleus. In brief, stem cells are the “mother of all cells.” Embryonic stem cells, for instance, can readily develop into any other cell.
Although each of our cells contains all the genetic material necessary to construct a human being, only embryonic stem cells have the ability to actually differentiate into any type of cell in the body.

Adult stem cells have lost that chameleon-like ability, but they can still reproduce and replace old, dying cells. As far as memory enhancement goes, interest has focused on adult stem cells in the hippocampus. It turns out that thousands of new hippocampus cells are born naturally each day, but most die soon afterward. However, it was shown that rats that learned new skills retained more of their new cells. A combination of exercise and mood-elevating chemicals can also boost the survival rate of new hippocampus cells. It turns out that stress, on the contrary, accelerates the death of new neurons.

In 2007, a breakthrough occurred when scientists in Wisconsin and Japan were able to take ordinary human skin cells, reprogram their genes, and turn them into stem cells. The hope is that these stem cells, either found naturally or converted using genetic engineering, can one day be injected into the brains of Alzheimer’s patients to replace dying cells. (These new brain cells, because they do not yet have the proper connections, would not be integrated into the brain’s neural architecture. This means that a person would have to relearn certain skills to incorporate these fresh new neurons.)

Stem cell research is naturally one of the most active areas in brain research. “
Stem cell research and regenerative medicine are in an extremely exciting phase right now. We are gaining knowledge very fast and many companies are being formed and are starting clinical trials in different areas,” says Sweden’s Jonas Frisén of the Karolinska Institute.

GENETICS OF INTELLIGENCE

In addition to stem cells, another avenue of exploration involves isolating the genes responsible for human intelligence. Biologists note that we are about 98.5 percent genetically identical to a chimpanzee, yet we live twice as long and have exploded in intellectual skills in the past six million years. So among a handful of genes there must be the ones responsible for giving us the human brain. Within a few years, scientists will have a complete map of all these genetic differences, and the secret to human longevity and enhanced intelligence may be found within this tiny set.
Scientists have focused on a few genes that possibly drove the evolution of the human brain.

So perhaps the clue to revealing the secret of intelligence lies in our understanding of our apelike ancestors. This raises another question: Can this research make possible the
Planet of the Apes
?

In this long-running series of movies, a nuclear war destroys modern civilization. Humanity is reduced to barbarism, but the radiation somehow accelerates the evolution of the other primates, so that they become the dominant species on the planet. They create an advanced civilization, while humans are reduced to scruffy, smelly savages roaming half naked in the forest. At best, humans become zoo animals. The tables have turned on the humans, so the apes gawk at us outside the bars of our cages.

In the latest installment,
The Rise of the Planet of the Apes
, scientists are looking for a cure for Alzheimer’s disease. Along the way, they stumble on a virus that has the unintended consequence of increasing a chimpanzee’s intelligence. Unfortunately, one of these enhanced apes is treated cruelly when placed in a shelter for primates. Using his increased intelligence, the ape breaks free, infects the other lab animals with the virus to raise their intelligence, and then frees all of them from their cages. Soon a caravan of shouting, intelligent apes runs amok on the Golden Gate Bridge, completely overwhelming local and state police. After a spectacular, harrowing confrontation with the authorities, the movie ends with the apes peacefully finding refuge in a redwood forest north of the bridge.

Is such a scenario realistic? In the short term, no, but it can’t be ruled out in the future, since scientists in the coming years should be able to catalog all the genetic changes that created
Homo sapiens
. But many more mysteries have to be solved before we have intelligent apes.

One scientist who has been fascinated not by science fiction, but by the genetics of what makes us “human,” is Dr. Katherine Pollard, an expert in a field called “bioinformatics,” which barely existed a decade ago. In this field of biology, instead of cutting open animals to understand how they are put together, researchers use the vast power of computers to mathematically analyze the genes in animals’ bodies. She has been at the forefront of finding the genes that define the essence of what separates us from the apes. Back in 2003, as a freshly minted Ph.D. from the University of California at Berkeley, she got her chance.

“
I jumped at the opportunity to join the international team that was identifying the sequence of DNA bases, or ‘letters,’ in the genome of the common chimpanzee,” she recalled. Her goal was clear. She knew that only
fifteen million base pairs, or “letters,” that make up our genome (out of three billion base pairs) separate us from the chimps, our closest genetic neighbor. (Each “letter” in our genetic code refers to a nucleic acid, of which there are four, labeled A,T,C, and G. So our genome consists of three billion letters, arranged like ATTCCAGGG.…)

“I was determined to find them,” she wrote.

Isolating these genes could have enormous implications for our future. Once we know the genes that gave rise to
Homo sapiens
, it becomes possible to determine how humans evolved. The secret of intelligence might lie in these genes. It might even be possible to accelerate the path taken by evolution and even enhance our intelligence. But even fifteen million base pairs is a huge number to analyze. How can you find a handful of genetic needles out of this genetic haystack?

Dr. Pollard knew that most of our genome is made of “junk DNA” that does not contain any genes and was largely unaffected by evolution. This junk DNA slowly mutates at a known rate (roughly 1 percent of it changes over four million years). Since we differ from the chimps in our DNA by 1.5 percent, this means that we probably separated from the chimpanzees about six million years ago. Hence there is a “molecular clock” in each of our cells. And since evolution accelerates this mutation rate, analyzing where this acceleration took place allows you to tell which genes are driving evolution.

Dr. Pollard reasoned that if she could write a computer program that could find where most of these accelerated changes are located in our genome, she could isolate precisely the genes that gave birth to
Homo sapiens
. After months of hard work and debugging, she finally placed her program into the giant computers located at the University of California at Santa Cruz. Anxiously she awaited the results.

When the computer printout finally arrived, it showed what she was looking for: there are 201 regions of our genome showing accelerated change. But the first one on her list caught her attention.