The Quest of Christof Koch

by David Dobbs

from Scientific American Mind, July 2005 

______________________________________________



Consciousness, people in brain science will tell you, is the greatest problem facing human biology and perhaps all of science. It essentially means solving the long-intractable mind-brain conundrum: How do our material brains – the most complex physical systems known — produce our immaterial but  vital sense of awareness? Scientists and philosophers of mind argue fiercely about how to solve it and whether it’s even solvable. Some say consciousness is illusory. (Try to counter that one — a real headache.) Others say consciousness exists but at too complex a level for humans to fathom, like quantum mechanics to monkeys. Still others believe consciousness will yield only when we discover new physical laws underlying its creation.

Christof Koch  rejects such skepticism. As one of the world’s leading consciousness researchers, he believes that consciousness is distinctly physical, that it can be described by existing laws, and that he, with help from collaborators and colleagues such as MIT’s Tomaso Poggio and Koch’s close friend and longtime collaborator the late Francis Crick, of double-helix fame, is on the way to figuring it out. The key to cracking this nut, says Koch, is to trace the “neural correlates” of (that is, the neuronal activity associated with) the simplest type of consciousness, which is the awareness of something we see.

“Some of my colleagues think I’m naive,” he says, “that this rather narrow focus won’t reveal the workings. And they might be right. But as a scientist, I think this is the most likely way to solve this problem.” Koch takes faith that biology’s Big Problems have so often fallen to a focus on the particular. Mendel discovered the mechanics of heredity by splicing  pea plants; Darwin saw the workings of natural selection in barnacles, birds, and dog breeding; and, more recently, neuroscientist Eric Kandel won a Nobel Prize (in 2000) when he revealed the microbiology of memory by studying sea slugs. Koch believes defining the mechanism behind the simplest kind of visual consciousness could similarly open the door to understanding higher levels of consciousness. He takes faith too in the highly supportive environment at CalTech, where he heads the Computation and Neural Systems program, in the aid of the twenty people in his lab, and in the stimulation he gets from sharing ideas with many colleagues and collaborators, from Kandel to France’s eminent neuroscientist Stanislas Dehaene, who think he’s on the right track.

Another Koch admirer is neurologist and writer Oliver Sacks, who has known Koch since Francis Crick introduced them in the late 1990s.  Sacks, who admits a bias because of his own fascination with the dynamics of visual consciousness, thinks Koch’s is “both the most fascinating and the most promising approach” to the consciousness problem. “There’s a brilliant directness to it,” he says. “And with his energy and his mental quickness – well, you have to give the man an excellent chance.”

Koch’s energy is indeed striking. This is a man who dyes his hair orange and purple and wears clothes in the same hues, all of which seem natural extensions of an incandescent intellect and a physical restlessness so profound that in his forties – he is 48 now — he has taken up running marathons and climbing big walls. He climbs as often as possible at the spire and slabs in Joshua Tree National Park, two hours east of Pasadena, and he has scaled big-wall test pieces in Yosemite, including the 3000-foot wall of El Capitan. He talks fast, a bottleneck of ideas and details creating an urgent pressure, with lots of hand gestures. The son of German diplomats, born in Kansas City but raised in Germany, Amsterdam, and Monaco, he sounds like a brainy Arnold Schwarzenegger. To refer to his subject he often rubs the top of his multicolored head with his fingertips, his long arm – he ‘s 6’4”— up and elbowy above him. He always seems hurriedly but fully engaged. In consciousness he seems to have found his ideal subject. He loves consciousness intellectually, as the most absorbing and fascinating scientific problem imaginable. And he loves consciousness phenomenally, as a thing to experience.

This became evident to me when I first heard his cowboy yell, near the end of a long day in New York. He had delivered two lectures to philosophers at New York University, made a round of visits to neuroscience labs there, then skipped dinner to give a riveting talk at the New York Academy of Sciences in the Academy’s mansion off Fifth Avenue, after which he answered questions from the bedazzled audience for two hours. Finally he escaped, and after a cab ride downtown to Pastisse, a fashionable West Village bistro, he and I pushed our way to the bar and ordered an ale. The beer, along with the vibrant room full of relaxedly chic people and the prospect of dinner, so pleased him that he emitted an impressive hoot. "YEEEEE-HOOOoooo!" he yelled. I looked around, but no one in the boisterous, beautiful crowd had noticed. Smiling, Koch held out his beer to clink glasses. “Wonderful!” he shouted, gesturing at the happy scene around him. “I love it!”

 
* * *
 
When he started investigating consciousness, Koch, in his late 20s and freshly arrived and untenured at CalTech, was told repeatedly that pursuing a theory of consciousness was professional suicide. Things have changed since then, as an explosion in neuroscience, particularly in the ability to trace the physical bases of various mental states, have made the problem more approachable. Every month researchers find new links in the obscure chain between sense and sensibility; most consciousness investigators think someone will pull the whole thing free in the next 25 years, possibly in the next decade. Whoever does will likely win a Nobel.

Koch got his start researching consciousness through work with Nobelist Francis Crick. After discovering the structure of DNA in 1953, Crick worked another two decades in England on microbiology and embryology before accepting an offer to the Salk Institute in La Jolla, California in 1976. Soon after coming there he became interested in the consciousness problem, seeing it as the great remaining unexplored question in biology. He and Koch met three years later at the Max Planck Institute in Germany, where Koch was finishing his Ph.D. in neural processing. In 1986, when Koch joined the CalTech faculty in Pasadena, two hours away from the Salk, the two began a conversation about consciousness that quickly bloomed into an ongoing collaboration, with countless phone calls, visits, dinners, and many joint publications. It was an extraordinarily rich partnership in which likenesses transcended their differences. Crick was a very distinguished 70 then, a whipsmart but ever-urbane presence most distinctly Brrritish. Koch, 40 years younger, seemed by comparison almost exceedingly colorful. But they shared a quickness of mind and intellectual irreverence, an appreciation of each other’s wit and warmth, and the conviction that disciplined, results-oriented science could solve this nebulous problem.

Crick died last summer. Koch misses him constantly. “I so often catch myself, after I hear about a new experiment or a new idea, thinking that this is what Francis thrived on. And that I would have called him to tell him about it and he would chide me gently or get intrigued and ask lots of questions. More than any scientist I’ve ever known, Francis could focus on the most important points but be willing to abandon an idea if something suggested it was wrong. So few can do that. He always had a sure sense of where to go.”

Koch and Crick agreed early to focus on visual consciousness, and Koch retains that focus today. He is not after the higher-order consciousness that allows us to dream, imagine a chain of events, or think our way through abstract problems. Rather, he seeks neuronal areas and physiological processes that produce the awareness of a particular sight. It’s a simple agenda of enormous complexity – a clean entrance, Koch hopes, to the labyrinthine workings of consciousness. “Seeing” something – being aware of seeing it — requires the coordinated work of multiple brain areas. Say you’re walking along the edge of a park, admiring a building across the street, when a bird enters your field of view. Your retina shoots an impulse down the optical nerve, through the thalamus — a small, egg-shaped structure near atop your midbrain (near the center of your head) that serves as a relay station through which all sensory except smell gets relayed to cortical processing areas — and then to the primary visual cortex, or V1, at the back of your head. But you’re still not aware of the bird. That happens, Koch asserts, only through a competition between a temporary coalition of neurons associated with the bird and other coalitions associated with other objects vying for your visual attention — the building you were admiring, the red car approaching down the block. Each coalition engages, by Koch’s estimate, not just the thalamus and V1 but other parts of the visual cortex at the brain’s rear as well as key cortical columns — bundles of nerves that run vertically through the cortex’s six layers— in the medial temporal and frontal lobes. It’s a winner-take-all contest. If the bird is striking enough or you favor birds, its attending coalition wins out, and it enters and dominates your visual consciousness. You stop admiring the building and watch the bird.

Why would we need such awareness? To serve as a sort of "executive summary" of reality, says Koch, that allows quick, effective action. He speculates that such consciousness developed at some point in mammals because an explicit attentional awareness conferred an evolutionary advantage in finding food, spotting and evading predators, and (later) negotiating social interactions within species. Though we’ve subsequently evolved higher conscious functions for more complex uses such as long-term planning, language, and abstract thought, this simple visual awareness came first and is likely simplest and so should yield most readily to investigation.

 
Koch and Crick’s strategy arose from careful study and imaginative contemplation of the neuroscience of the last 20 years. In the last decade, the larger neuroscience and philosophy-of-mind community has come to consider it one of the most promising empirical approaches. Koch must now try to fulfill that promise by adapting it to all that is to come. Because he is looking at the big picture (if in a concentrated way), he must track, evaluate, and account for every major finding in neuroscience while pushing his own investigations. Most of his own research focuses on identifying particular nodes and links forming the neural pathways that filter and create particular visual percepts. This often involves using cutting-edge tools, such as brain scans, electroencephalography, or neuronal probes, to study monkeys or people viewing objects, faces, or perceptual-study staples such as bistable illusions (see sidebar). As these investigations reveal more correlations between specific conscious perceptions and particular neuronal activity, Koch must find ways to test those correlations by turning off and on the suspected neural components in animals and, eventually, humans. Such “switching” methods presently include electrical stimulation and nerve freezing; future techniques may include gene-expression switching that temporarily halts the certain functions (such as neurotransmission) of targeted cells. Koch and others have made remarkable progress in all these areas in just the last 5 years. But it is unpredictable work, and the possibility of following the wrong trail haunts all pursuers.

Yet Koch appears energized by challenge. Actually he seems energized by everything. At Pastisse he easily lasts till midnight, buoyed by sea bass and a bottle of Beaujolais until, post-dessert, with a glass of Armagnac at hand, he tells how crushed he was when his kids left for college four years before.

“Oh it was terrible!” he says, laughing, talking as fast as ever; Koch does not use commas. “It provoked the classic midlife crisis. In which of course I am supposed to get a sports car and drive off with a student. But I didn’t. My wife got a sports car. A Porsche. I  got a new kitchen – new cabinets, range, black marble counters.” He waves his hands along the appropriate planes to put cabinets and counters in place. “But it wasn’t enough. The house is too quiet. Even with the three dogs! So I climb.”

A few minutes later we exit into a snowstorm. The wind smacks wet flakes into our faces. We are getting ready to part when I remember I have brought him a gift, a collection of mountaineering accounts by the British climbers Peter Boardman and Joe Tasker. He wants to see it immediately, so we huddle in a doorway and look at photos of Boardman and Tasker in the Himalayas, exposed on the planet’s most austere heights: Changabang, Kangchenjunga, Gaurisankar.

They’re dead now, I tell him, lost on Everest in 1982.

 “But still,” he says. He is entranced, shaking his head. “Look at this.” It is Boardman and Tasker ascending the knife-edge ridge of Gaurisankar – an impossible, insanely committed climb they somehow made and lived through. “I mean, to do this -- can you imagine? What a thing! I love it.” He is so delighted he punches me on the arm and gives another cowboy yell. Then he heads off through the snow.