Out on the Frontier of Neuroscience
with a World-class Researcher
by Tony Daniel
There are whole millennia of human history filled with gibberish spoken about the mind, the soul, the brain, and about what it means to be a conscious person. For science fiction in particular, such speculation seems to be the first and last refuge of the writer with not much to say and it has produced a distinct genre of bellybutton-lint gazing literature over the years. Most of these products (I hesitate to call them books or stories) are about as interesting as having to sit through an inescapable encounter with someone who insists on recounting a particularly random dream to you—that is, they are tales full of logic holes (and therefore not fantasy, which depends on consistent internal logic for the magic to be any fun) and devoid of plausible storylines (and therefore not SF, which lives and breathes plausibility).
In a word, crap.
Which is annoying, because the hard facts about what we know and don’t know about the brain are far more interesting than ungrounded speculation and make far more entertaining stories. What’s more, those facts are getting more interesting almost moment to moment these days.
I talked recently with my friend Dr. Michael D. Devous, Sr., a Dallas-based brain scientist who is a powerhouse researcher in neuroimaging and neuro-pharmacology. Mike is an M.D.-and Ph.D.-bearing professor of radiology at the University of Texas Southwestern Medical School in Dallas, where he’s also the Director of the Neuroimaging Core for the Alzheimer’s Disease Center and of the Neuroimaging Core of the North Texas Traumatic Brain Injury Model System. Mike is also an avid science fiction reader and (one of these days!) an aspiring SF writer.
Neuro-imaging, in particular the advances in the functional MRI devices brain scientists use to see inside of brains, has revolutionized what we know about what lies inside our skulls.
“The hallmark of brain study ten to fifteen years ago was the autopsy,” Mike says. “Now the functional MRI allows me to view brain structure in exquisite detail while you’re still alive. With an MRI, I can watch you go through an entire perception and the associated memory retrieval, identification and emotions associated with that percept in one picture per millisecond intervals. I can literally play back a movie of your having a perception or an emotion or both.”
What Mike sees are networks.
“The brain is not unitary as we usually think of it. The organization of the brain is regionally dependent and the brain is a network of networks operating in a massively parallel manner. From what I can actually see and prove, we are beings who are organized in a bottom-up manner when it comes to cognition.”
Before the coming of advanced MRI techniques, the normal method for attempting to understand brain function was through lesion studies—that is, through studying people with severe head wounds or disease-produced injuries to various regions of the brain. This led to a great deal of talk about “areas of the brain” that are responsible for this or that mental function. Speech was said to be “concentrated” on the left side, and, say, music on the right. What Mike sees is much more interconnection. Brain structures are more like traffic hubs expanding into networks throughout the brain, and not really anything like the “seat” or governor of this or that function or ability.
These networks are remarkably similar among people, but they are not identical.
“There are ten billion nerve cells in an average human brain each branching into about ten thousand connections. A baby is born with many, many more of these connections than an adult. Maturation cuts connections rather than adds them. The technical term is dendritic pruning. One of the things we’ve learned recently is that you can grow more neurons and you can regain a good deal of brain plasticity and functionality. It’s all a matter of creating the proper conditions.”
Case in point: cochlear implants. These devices for the deaf have become extremely common in the past decade, and their sophistication has increased enormously. What started out in the 1990s as a gadget that could only signal “loud” and “soft” sounds to the auditory nerves now allows a huge swath of previously deaf people to hear and understand speech itself. For many deaf children who receive implants before the age of five or six, you really can restore normal hearing with an implant—that is, until the batteries need changing (which fortunately isn’t a difficult procedure).
But there was a class of deaf people for whom the new implants didn’t work. Mike and his team realized that the issue wasn’t the implants or even the nature of the person’s deafness, but was a network issue within the brain.
“The implants were functioning; the brains were receiving the signals. It turns out that real speech is quite bilateral,” Mike says. “When the pre-processing distribution doesn’t work, the brain doesn’t know how to proceed and this is interpreted as silence.”
Mike knew a particular class of drugs that were good at unjamming certain neural pathways: amphetamines. In an experiment that has since become a common treatment, Mike used a targeted dosage of amphetamines to do just that with a group of cochlear implant “failures.” The outcome was dramatic. Many of these people had a fourfold increase in hearing within eight weeks. And, unlike the dopamine-pumped souls in Awakenings for whom neuro-pharmacology was more a fleeting hope than a promise, Mike’s amphetamine-induced hearing gains were permanent.
“Amphetamines stimulate learning. The problem is, you need to take them in the proper environment and in the right amounts,” says Mike. “But I see no reason they might not be used to enhance mental function in the next ten to fifteen years. We’re on the edge of a mix of technology and pharmacology that may be able to enhance normal brain function. I see no fundamental reason why it would be impossible to increase a measure of functionality—say, IQ—by twenty to twenty-five percent in the near future.”
It’s a matter of recreating the environments in which brains learn and grow in ability. With fMRI and other imaging, Mike is able to actually see this happen in real time, and experimentally verify what works and what doesn’t to create or restore neuronal plasticity and brain network complexity.
“Right now I can look at an MRI and tell you, by seeing how certain areas light up and which do not, whether a word you hear is a noun or a verb,” Mike says. “Other people have done studies where they induce temporary emotional trauma—they show pastoral scenes and then flash on a few seconds of, say, a car accident or murder scene—and they have accurately mapped the neuronal state that such experiences produce. Turns out, they’re remarkable similar across humans as a species.”
I asked Mike to look ahead to the near and mid-term future and make a couple of predictions.
“For one thing, I think we’ll cure Alzheimer’s in ten to fifteen years,” he says. “We have to do so, or we’re going to have the mother of all health care crises on our hands. Alzheimer’s accounts for 60 to 75 percent of all dementias and, with the Baby Boom maturing and average lifespans increasing, huge parts of the population are being affected by it. Right now in the economically developed world, half the aging population is going to make it to their late 80s. I expect life expectancy to increase into the 90s and up to 100 years soon, and as we cure and mitigate heart diseases and cancer (which we’ve become very good at doing), we open the way for Alzheimer’s and other cognitive impairments associated with aging.”
There are two apparent culprits in Alzheimer’s. The necessary-for-normal-cell-function protein amyloid is normally broken apart for reuse by a cleaving process in cells. When this system breaks down, a clump of amyloid amino acids is produced known as beta amyloid—and unfortunately beta amyloid is toxic to nerve cells. Another substance known as tau protein used by cells to build their microtubules is also an Alzheimer’s culprit, as overproduction of tau also kills nerve cells.
There are current therapies being feverishly researched to reduce or inhibit beta amyloid production. Dealing with tau overproduction still lies on the research horizon.
“What we can do with functional magnetic resonance imaging, or fMRI, is accurately diagnose Alzheimer’s at an early stage. If we develop therapies to reduce or prevent beta amyloid build-up, we’ll then be able to nip the disease in the bud,” Mike says. “I expect that in a few years getting an Alzheimer’s MRI screen at, say, age 50 will be as common and widespread as having your prostate checked or any other age-dependent screening procedure. I fully expect to see diagnosis and treatment in the economically developed world within about fifteen years or so, maybe sooner.”
Mike sees even more change in the mid-range future. “We’re nowhere near getting portable fMRIs at this point or implantable devices that can give you a readout of your brain state. It’s going to be an expensive device for some time. But the imaging research is going to pay off in so many ways, some of them quite soon. I suspect we’ll see enhancement in the military first just because they have more concentrated money to throw at it. And soldiers are expected to undergo more dangerous procedures than civilians. That’s just the way it is.”
Mike thinks that sensory extension interfaces will be the first enhancements that will come along. According to Mike, the military is already working on inducing infrared perception that can be switched on and off in human vision. And implantable communication and auditory-enhancement chips are a logic extension of present-day cochlear implant technology.
“As far as the big bugaboo of using pharmacology to reduce or eliminate inhibitions and thus allow soldiers to kill with more emotional ease—I just don’t see it. For one thing, our inhibitory networks are part and parcel of our frontal lobes. That’s one of the things our frontal lobes do, one of the things that makes us human. If you turn off the inhibition to kill, how do you tell the brain when it’s all right and when it’s not all right to kill? You might have soldiers killing their generals or civilians when they get home. It’s not something that will convey any military advantage. Quite the opposite. I don’t see it happening.”
For the rest of the population, Mike predicts significant gains in cognition in the next few decades.
“There’s a certain form of extreme epilepsy in infants that calls for a hemispherectomy—that is, destroying half of the infant’s brain,” Mike say. “If this isn’t done, the child’s chance of dying is almost one hundred percent. What we’ve seen is that in cases where this was done, the children who then survive turn out to be—normal. By age twelve or so there may be a few tests that show some slight impairment in certain areas, but by and large what you have is a normal child. This fact speaks volumes about what the brain is capable of. Think about it: we can get by fine on half a brain. It’s proven. So there’s obviously a lot that can be done with the structure evolution has given us.”
We might surmise that there’s something special in having a bicameral, dual-hemisphered brain.
Not so much.
“All the talk about people being left-brained and right-brained, about right-brained people being more creative and left-brained people being more analytical is interesting—as talk. It doesn’t really hold up empirically.”
According to Mike, a two-hemisphere brain is common among animals, even some invertebrates, and is probably a reflection of the need for depth perception and three dimensional manipulation for creatures that are bilaterally symmetric.
The secret to human mental ability, says Mike, is the gene that allowed primate brains to begin enfolding. This exponentially upped the amount of surface area of the brain within a given volume. Because of cell mechanics, density can’t really increase, so surface area is where it’s at as far as cognitive function goes in animals.
(Incidentally, according to Mike, the brain-enfolding gene has been introduced in some experimental mice, but the mice babies die in the womb. It seems the super-smart mice of N.I.H.M. still lie in the future. Whew.)
One of the tests of a theory of mind—that is, an understanding of one’s own individuality—is the so-called “dot test” where a bit of paint or rouge is put on a subject’s face and he or she is shown a mirror. If the subject moves to wipe the dot off his or her own face and not the mirror, it’s assumed there’s a level of personal awareness, or at least a facsimile thereof, present in the individual.
“When we see this in birds or other non-mammalian species, it’s very likely something else other than a theory of mind at play,” says Mike. “With birds, it’s a kind of mating behavior, because it goes away immediately when it’s no longer useful for courting. And we can design sophisticated ‘dot tests’ that take into account an animal’s physical make-up. What’s amazing is how extraordinarily few animals exhibit it. Basically some primates, dolphins, and humans. Dogs and cats do not. Pigs might.”
Mike anticipates a combination of technology and drugs that can create environments where learning, say, new skills, or developing abilities that others possess and that we lack might be induced.
“The abilities of what we used to call ‘idiot-savants’ are obviously present in the human brain. These people are born with them or acquire them. But usually these people have to give up some other functionality to support their abilities. What if we made it so you could acquire these abilities, but didn’t have to give up others? We’re learning how to do this through electronics and chemistry. It may seem strange at first, but look at those cochlear implant patients and beyond. All the data suggest that pretty soon you’ll adapt and forget you’re wired. We’re on the edge of a mix that will enhance normal brain function and take people to a different cognitive level. Many people alive today will live to see this happen. And it might well happen to some of us.”
Copyright © 2011 by Tony Daniel