by E. Paul Zehr
Incredibly, a recent study showed that including sensation from a robotic limb improved the ability to learn brain-machine interface commands. In 2010, Aaron Suminski, Nicholas Hatsopoulos, and colleagues at the University of Chicago used a “sleeve” over an animal’s arm to help train monkeys to move a cursor on a computer screen based on recording activity in the motor cortex. This is just like the procedures for brain-machine interface we talked about back in chapter 3. The crucial difference was that the scientists at University of Chicago allowed the monkeys to use visual and somatosensory feedback together. Those monkeys learned how to control the cursor much faster and more accurately! I think this would likely have an effect on embodiment as well. This awaits future research.
Embodiment can arise from extensive use and practice with tools and devices. It is highly likely that this also occurs with extensive training with almost anything that is not part of the body naturally. This is also why learning to play a sport that uses tools—think golf or tennis, for example—is so challenging. This is probably because these tools or implements have not been extensively calibrated and mapped as parts of our physical bodies. Those somatosensory and motor maps have been continuously developed and recalibrated over all the years of your life to reflect your body size and habitual activities. But you use your body every day, and it has always been there for you. In contrast, the particular implements or tools that we use haven’t been with us all the time and we don’t use them continuously. Those maps we have for our bodies have to be able to integrate and incorporate the tools into our physical perception of ourselves. This is what is meant by embodiment. It does seem that, while these changes certainly do occur, the changes in our body maps are weaker than those for our actual body parts.
Because of that more practice—or maintenance activity—is needed to keep those maps strong and intact. In my own physical activity experiences in martial arts, I can certainly attest that complex techniques and movement patterns with empty hand are easier to initially learn and subsequently remember than are techniques and patterns based around weapons. As a result, it is much, much easier to lose track of, forget, or lose skill with weapons technique than it is with the empty-hand technique. Empty hand training uses all the “weapons” of the body that have been part of your body since birth. Weapons use involves tools. And what is a more complex tool than an Iron Man suit of armor?
By the way, this kind of embodiment and plasticity can occur even in actual tool use in humans with no neurological damage. Lucilla Cardinali, along with other French and Italian scientists, performed a fascinating study to look at this. They developed a long (about 40 centimeter, 15.5 inch) handled extension that had a “grabber” at the end. By squeezing the close end, it was possible to pick up objects and move them around. This was kind of like the grabber that can be seen everyday in parks and streets that cleaning staff move about picking up refuse and discarded items without having to bend down. In the study Cardinali and colleagues had people practice reaching with the grabber. Their research showed that using the grabber changed the movements of the arm even without using the grabber! Even more interestingly, the “aftereffects” due to using the grabber tool affected later simple pointing movements and also the perceived length of the arm. Participants had the impression that their arms were actually longer. The idea seems to be that the somatosensory schema of the body was changed by using the tool and the change had a general effect for many behaviors. Maybe even for Iron Man? In the 2007 Extremis graphic novel, after using the new suit Tony talks about how the suit is “wired directly into my brain. I control the Iron Man with thought. Like it was another limb.” This would mean some process like that shown in figure 6.2 would actually have to be occurring in Tony’s brain.
Iron Man in Space
Embodiment could apply to armored exoskeletons as well. Or spacesuits. I asked David Wolf from NASA about his experiences in space using a spacesuit. David is one of those astronauts who is an extravehicular specialist. That means he has spent a lot of hours literally in space, as in outside the spacecraft. His total time (including NASA and Russian MIR missions) is over 40 hours. In addition to that he has had more than 800 hours of water-based training wearing a spacesuit on earth. He has logged a total of 168 days, 8 hours, and 57 minutes in space. Approximately—but who’s counting! Wolf explained to me that over time, wearing the suit is to “become one with the suit” (who does that sound like?). Eventually, wearing the suit “is like putting on your own armor and your old familiar tools…. It gets easier.” This resonates very well with the idea of neural plasticity associated with learning how to use a new tool we talked about earlier. In this case a tool you wear over your entire body. By the way, this being a book anchored on Iron Man, I did ask Wolf about comic books and his favorite character. He likes Superman, for the record.
I also spoke with David Williams of the Canadian Space Agency. (All right, I admit it. Yes, I only spoke with astronauts named Dave in honor of the book 2001: A Space Odyssey by Arthur C. Clarke.) Williams, now a professor at McMaster University in Hamilton, Ontario (coincidentally, I am a MAC alumnus, just saying), told me that “you’re as good as your training.” It all comes down to the operator, in effect. He also emphasizes the role for mental imagery and rehearsal to memorize and perform sequences as rehearsed. This is to help “train like you fly, fly like you train.”
Let’s close this chapter with a few comments about how fun—or not—it would really be to wear a suit of armor for prolonged periods. Going back to David Wolf, he said that it “sure feels better” to get the suit off and you are “very happy to get out of the suit” and that “wearing it for long time is like being in a tight balloon.” Additionally you have the concern about depending on the life support from the suit the entire time it is on. It is “probably like a race car driver when he gets out of the car after a race”; you are “hot, tired, hungry, and have been working at a very high level of peak concentration for a long time.” In the comics this was also noted by Tony Stark’s trusted assistant Pepper Potts. In the story “World’s Most Wanted, Part 7: The Shape of the World These Days” (Invincible Iron Man #14, 2009), Pepper has made use of a custom-designed armor suit for herself (Tony is on the lam). She goes on to say “it’s been nine hours in this suit, and, no offense, but if I don’t get to get out and take a shower soon, I’m going to start screaming.” With that, let’s move on.
The Next Decades of Iron
“I Can Envision the Future”
The next phase of Iron Man project development would require getting around the biological delays and control issues related to relying on physical movement to drive Iron Man’s activities. The steps in this phase each would involve a slightly more invasive integration with the nervous system. The first is to get stable motor control by using Tony’s own nerve signals as triggers for activating the motion of the suit. To apply the existing technology of basic neuroprosthetics to Iron Man would require improved processing to more effectively use the nerve signals for controlling complex movements. This would take about three or four years. The next step would be to get around the delays and control problems that go along with using measurement of muscle activity. Tony would instead try to use direct brain commands for moving the suit and would need to develop a suitable brain-machine interface. The basic technology to do this exists, but it typically involves surface electrodes on the scalp of the human head which has limited control options.
These kinds of brain recordings provide only limited two-dimensional (e.g., up/down, side to side) movement control; they could only be used for controlling a paper-thin Iron Man moving across the pages of a comic book. To be more usefully applied in three dimensions, Tony would need to spend another five years improving the understanding of brain output as a signal for controlling the armor. He would then likely try to use the signal recording with the highest content: direct single-cell neuronal recordings. The technology to get basic information for controlling simple arm movements
is available but has been mostly restricted to studies of the monkey. Some limited information has also come from studies of patients undergoing neurosurgery. Moving forward with this technology would take another five years. During this time, an improved knowledge of brain output from neuronal recordings would be needed, as would increased safety for recording from the human brain for prolonged periods. We are now almost 30 years into Iron Man development, and he would still be able to execute only rudimentary walking, lifting, and striking movements—and only by Tony paying strict attention and concentrating fully on the task at hand. More work remains. Tony continues to toil late into the night. Just about every night.
In the fourth decade of Iron Man R&D, we move into areas that exceed what is possible—at least currently, and maybe forever. There are some significant limitations that would arise even with an armor interface like the telepresence unit. To address these issues would require some kind of direct meshing between Tony’s body (primarily his entire nervous system both sensory and motor) and the Iron Man armor, which could only be achieved through some as-yet unrealized nanotechnology. The closest description for this is the Extremis armor, and this technology does not yet exist. Not even a little bit … At all. The good news is that nanotech research, particularly biomedical applications, is a field that is rapidly expanding. An additional hiccup is how to deal with rejection by the immune system of any such interface and how the inflammatory response can be controlled so that the interface could be maintained over time. So, it is not possible to identify a timeline for this next stage. One last thing that Tony would need is the physical training required to become fully comfortable and competent with the Iron Man suit. This adds another five to seven years and gives a total projected timeline for inventing Iron Man and putting him into service of almost 40 years. Inventing, developing, and bringing Iron Man to reality would truly be a life’s work. But what a life!
PART III ARMORED AVENGER IN ACTION
If we build it, what will come?
CHAPTER SEVEN Trials and Tribulations of the Tin Man
WHAT HAPPENS WHEN THE HUMAN MACHINE BREAKS DOWN
You know how dangerous a drunk is behind the wheel of a car? Imagine one piloting the world’s most sophisticated battle armor.
—Tony talking to Cap about responsibility while in the suit, “Civil War—Rubicon” (Iron Man / Captain America: Casualties of War #1, 2007)
Ever notice how your PC can act funny and only you’ll notice? An app takes a half-second longer to launch. It cycles longer on startup … I’ve started to notice little … things … with the suit. Not big enough to be glitches, and not big enough to trigger any alarm bells. But something’s up.
—Tony Stark reflecting on small problems with his suit, “The Five Nightmares, Part 1: Armageddon Days” (The Invincible Iron Man #1, 2008)
Being a superhero is hard work. It is even harder if you are a mere mortal and not an alien from the planet Krypton or the victim of an accident that leaves you with the ability to sling webs. Superman flies over the earth to decompress and Spidey climbs a tall building to get a new perspective. What does Tony do to cope with the demands of his chosen career? As you will see in this chapter, his solutions—frequently alcohol abuse—usually backfire on him. We will explore what happens when Iron Man gets buffeted by bomb blasts and when he needs to call the geek squad to fix bugs in his system. And I also have a little surprise for you in this chapter—a plausible origin story for Tony Stark’s heart problem.
Not Shaken, Not Stirred: Intoxication and Iron Man Don’t Mix
A drunk running around in an Iron Man suit. It is difficult to imagine something more poised for disaster than putting someone in an exoskeleton that amplifies strength and then having them get drunk and impair their ability—and their impulse control. This scenario played out in the Iron Man comic books and was shown in the extreme in the movie Iron Man 2. In both comics and in the movies, Tony Stark is always seen as having a penchant for a few drinks and even struggling with alcoholism. In the 2010 movie, Tony’s drinking problems come to a head at his birthday party, where he drinks to excess and is intoxicated in the Iron Man suit. He uses many of the repulsor weapons systems and then gets into a huge battle with Jim Rhodes (which ends with Rhodey flying off in the War Machine armor). Let’s consider the many ways in which alcohol would impair the performance of Iron Man.
Alcohol (in the form of ethanol) has some odd effects on the body. Initially and in reasonable quantities, alcohol generally can be relaxing and even somewhat euphoric. A large intake acts on the nervous system and produces problems of coordination, vision, and balance. It does this by affecting the brain (which we will look at more later) and the communication among the neurons themselves. Alcohol interferes with the coupling between excitatory (glutamate) and inhibitory (GABA) neurotransmitters and their receptors (NMDA and GABAa) on neurons. This interference changes the way in which neurons function and respond to different inputs and varies depending on the dose (e.g., how much a person has drunk).
At lower blood concentrations, ethanol is known to affect certain types of GABAa receptors strongly. This effect causes much of the relaxation and suppression of behavioral inhibitions that alcohol initially produces. With higher alcohol intake, there is an interference with neurotransmitter binding to the NMDA receptor. Activity in this pathway is closely related to a cellular process called LTP (long-term potentiation) that affects memory formation and learning. This effect of alcohol is likely what gives rise to blackouts. When NMDA receptors are interfered with repeatedly as in chronic alcoholism, it may help stimulate a cellular response in neurons known as “apoptosis,” which is a type of cell death. This helps account for some of the longer and more pervasive changes that happen due to the death, and thus the functional loss, of neurons.
It also seems that alcohol can affect the activity of sodium channels in axons. Since movement of sodium through this channel is vital to the excitability of a neuron and its ability to send signals down its axon, this is a very important effect. So, the story so far, too much alcohol is bad. Especially if it is chronic in the form of alcoholism. And, especially if you intend to hop into a robotic iron suit that connects to—and amplifies the ability of—your nervous system.
Beyond damage to the neurons, many other long-term physical changes to the nervous system can happen with chronic alcohol abuse. A common one is so-called nerve damage, which leads to “neuropathy.” This basically means that axons in nerves are damaged and don’t work as well anymore. Some of the more obvious effects of neuropathy are the slowing of information flow along sensory and motor nerves, which can result in sensations that are often felt (or not felt, actually) in the hands and feet. Also, even reflexes can be affected and this can make the control of movement much slower and of lower quality than ordinary. Chronic alcoholism can contribute to other significant changes in the central nervous system, including damage to parts of the brain essential for movement control.
While extensive damage can occur to many parts of the nervous system, I want to just focus on the cerebellum here. The cerebellum is vitally important in helping with regulating and altering movements that are ongoing and in helping with balance control. It is also necessary for correctly initiating and coordinating movement, particularly for the arms and legs. That means anything that interferes with or damages the cerebellum will impair the ability to produce movement. At this point, it is worth pointing out that more than one-half of the neurons in the brain are found in the cerebellum, this despite taking up only about 10% of the volume of the brain—those neurons are really packed in there! This means that the cerebellum is particularly sensitive to the effects of alcohol impairment.
In fact, the large suppressive effect that alcohol consumption has on the function of the nervous system is the underlying basis for the driving “spot check” tests that the police use if they suspect someone is driving while intoxicated. For example, a task like closing your eyes and reaching up to touch your no
se requires the careful regulation given by the cerebellum. So does speech. As a result, if there is a problem with performing these smoothly, there is suspicion of alcohol impairment. Unfortunately, the flip side of this is that sometimes people who have had cerebellar disease or damage of the cerebellum are thought to be intoxicated when they are not.
Figure 7.1. A cross-sectional image of the brain. The area of the cerebellum is shown traced for a normal brain (black line) and for a chronic alcoholic (gray line). Note how the cerebellum, which is involved with movement and balance, is much smaller in chronic alcoholics. Courtesy Patrick J. Lynch.
Figure 7.1 shows a cross-section of the brain. The area of the cerebellum is shown traced for a normal brain (black line) and in one from a chronic alcoholic (gray line). This image is similar to one that would be obtained through magnetic resonance imaging. The cerebellum is the bit of the brain at the back and base of the skull and contained in the traces drawn on the images. Notice how much smaller the cerebellum is in the alcoholic. This clearly shows the anatomical changes that produce the behavioral deficits occurring in alcoholism. Alcohol impairment carries with it other effects on the nervous system, including cognitive problems that aren’t present as part of cerebellar disorders, though. Some of the behavioral and cognitive effects that occur in alcoholics are thought to arise from other degenerative changes in the brain. This is particularly the case with links between the frontal lobes and other parts of the brain. The sum total of this is the impulsive behavior and cognitive problems seen in chronic alcoholism.
