3

The Check

His grandfather called him into his room.

He handed him a check.

“Go,” he said.

More than a hundred years ago, a gifted doctor named Paul Ehrlich lived in Berlin. His patients adored him. He always had a good word for them. Where other doctors shrugged, he always had a suggestion that lent them hope. Ehrlich was ahead of his time. He complained publicly that women were paid less than men. And in medicine, he dedicated himself to new and unprecedented methods.

At the time, accelerating industrialization was transforming the Western world. Railroads and assembly lines set the pace. New technologies and new sciences were changing the way people lived: steam power, electricity, physics, and chemistry. Only the medical profession seemed stuck in its ways. The epidemics of the age—tuberculosis, diphtheria, cholera, and syphilis—were still widely viewed as divine judgments. Great bravery was required to shake up the status quo, and doctors like Robert Koch, Emil von Behring, and Ehrlich rose to the occasion. They wanted to introduce the burgeoning sciences into their field. They withdrew from hospital bedsides and went to their laboratories. Drawing on advances in microscopy and chemistry, they discovered that mass epidemics weren’t the work of a vengeful God—or, as more secular thinkers would have it, the result of vapors pouring out of holes in the ground—but instead were caused by tiny living things called bacteria.

When Ehrlich withdrew to his lab, his colleagues rolled their eyes at him. They distrusted all this new mumbo jumbo. Chemistry! Staining cells! But he remained hunched over his microscope. Through constant experimentation, he discovered chemicals that made certain tissue cells visible for the very first time. He discovered an unknown form of blood cell, leukocytes. He became an immunologist and, in 1908, he received the Nobel Prize in Medicine.

Ehrlich’s hospital colleagues accused him of neglecting the sick. Diphtheria was killing fifty thousand children a year at the time. But Ehrlich no longer saw it as his primary mission to cure diseases. He wanted to prevent them instead. The pathogens shouldn’t be allowed to get to work in the first place; the toxins would be rendered harmless by “antitoxins.” Ehrlich wanted to vaccinate people.

Another independent spirit, Emil von Behring, built on Ehrlich’s work and developed a vaccine, diphtheria antitoxin. It was distributed in vials inscribed “per Behring and Ehrlich.” Within a year, child fatalities were reduced by 75 percent.

Ehrlich started experimenting with so-called magic bullets, substances from the realm of chemistry that could kill microbes without harming humans. He tested these pellets on animals. Chemicals in medicine? The elders shook their heads. Ehrlich was banned from the Charité hospital in Berlin. But several years later, his critics had to acknowledge that the “magic bullets” worked, just as antibiotics and chemotherapy would later. Ehrlich revolutionized medicine and founded a new kind of pharmaceutical research. More than a century later, medical science still follows his two main principles: microscopic analysis and animal testing.

Bo-o-o-ring. Henry couldn’t stand it any longer. Day after day, he drove to the university and sat in the stuffy lecture halls, where professors lectured and students listened.

He had learned a lot about the human body and brain in the beginning, and found his internship in the hospital interesting, too, particularly in the pediatric ward. He loved children and wanted five of his own, but that required a wife and a bit of free time, and his whole life up to that point had been dedicated to studying. He got the basics down quickly and felt ready to delve into the nitty-gritty: the structure of the brain and all the exciting new ways it would be explored in the future. At least, that was his hope. What his professors offered instead, on their blackboards and overhead projectors, was a disappointment. How little humanity knew about the brain! How far we were from solving the mysteries of thinking and feeling! And how gutless the attempts had been to change that! The lectures were only marginally concerned with providing actual understanding and certainly didn’t encourage further exploration. They just taught you how to correctly apply the old teachings.

So, this was the life of a neurologist: You inquire about the symptoms, pick up the book, find the appropriate entry, and name the disease. You find that there are, say, five medications to treat it. You prescribe the first one. And if it doesn’t work, you prescribe the second, the third, the fourth, the fifth. You rarely know why those particular medicines work. In most cases, they don’t even promise a cure, just relief from the symptoms. Alzheimer’s, Parkinson’s, schizophrenia, and autism—all entirely incurable.

Henry started skipping class. He preferred going down the hallway to the laboratory wing, the wing of the explorers. How he loved their world! The labs buzzed and blinked, smelled like formaldehyde, and were giddy with the spirit of inquiry and adventure. Doctoral students and professors immersed themselves in Ehrlich’s dyed cells and explored organs and organisms. Henry simply joined in. He greeted them like colleagues, and when they greeted him back, he nodded knowingly, said something smart, and kept coming again and again. Eventually, he was one of them, wearing his own lab coat over his clothes. “Oh,” he said, “the gentlemen are isolating nephrons,” small functional units of the kidney that filter water in the body. Henry let the nephrons dry like a sponge, added saltwater, and then watched the units drain all salt from the water.

Let someone else become a doctor, he thought. I’ll become a scientist instead, a researcher. Like Ehrlich, he wanted to fight the scourges of his time: Parkinson’s and ADHD, depression, and autism. Those were the new epidemics, the number of cases growing exponentially year by year. He would write his dissertation on brain cells, how they communicate and understand each other. This question contained humanity’s essential mystery: Who are we?

First, he would have to transfer to a research university. Several professors recommended the Weizmann Institute in Israel, one of the most influential research centers in the world. It had already produced three Nobel Prize winners, as well as crucial medicine to fight cancer and multiple sclerosis. Unlike most other universities, it was future-minded, one of the first places with a so-called mainframe computer. Henry applied for a scholarship, and, what do you know, they ended up giving it to him. Him: twenty-six-year-old Henry Markram from the Kalahari. He flew home proudly.

A grand welcome. The boy was back. What a surprise! If he had let them know ahead of time, Mum would have baked a cake. He had gotten so thin. Wasn’t he eating enough? You can’t work all the time, you know. Your brain needs food too. They sat down for dinner.

“I’m moving to Israel,” Henry announced.

The family stopped chewing and chatting. “You’re what?”

“I’m going to the Weizmann Institute.”

“What?” “Huh?” “Where?” “Israel? Why would you want to go there?” “Isn’t it dangerous?” “No, you’re not. You’re staying here!” They continued in this manner.

“I want to do research,” Henry said. “The Weizmann Institute is famous for its research.”

“What research?” “We thought you were becoming a doctor! You said you wanted to help people.” “Spending all day in the lab. That’s no way to live.” “And how do you intend to feed your family? The salaries in science aren’t exactly up there, you know.”

Henry got an earful from his parents. This was not what they expected when they paid his high tuition. They certainly wouldn’t support a whim like this. Like so many sons and daughters before and after him, Henry had returned home feeling mature and confident only to be reduced to adolescence in a matter of hours. Discouraged and gloomy, he sneaked upstairs to his childhood bedroom. Someone called his name. It was his grandfather, who used to drive him out of bed with a whip and never had much to say to him. Grandpa had dedicated his life to the farm. He never left. But now he called Henry into his room and handed him a check. “Go,” he said. That was it, but there was love in his voice.

Henry never understood why his grandfather helped him. He never got to ask. When he returned years later as a promising neuroscientist, bestowed with so much early success that the whole family welcomed him proudly—their son, the great scientist—his grandfather was dead. The old man never found out what had become of his investment. Henry never got the chance to tell him how the Weizmann Institute had changed his view of the world. He would have done so with pleasure. He would have told his grandfather all that he had learned about the cerebral cortex, which contains almost everything that makes us who we are: intellect, memory, emotions. Our brain is like the universe, he would have said. It has as many cells as the sky over the savanna has stars.

How a person thinks, feels, and develops is determined by interactions between their neurons. When a child’s brain grows, the child isn’t growing more neurons but augmenting the connections, the pathways, between them. If those pathways are disturbed, that changes how a child develops.

Neurons transmit everything you hear, see, and feel: that piece of music you were playing on the old stereo system, the light from the lamp on the front porch, the itchy socks your grandmother knitted for you. When you turn on the light, neurons get excited. When you try on those socks, a few neurons may even pop. When the radio plays a piece of music, the neurons become calm, almost depressed. Depending on whether the stimulus is light, touch, or sound, neurons behave differently, sending different messages.

And while the stars over the Kalahari remain beyond our reach, in the universe of the brain, you can intervene. While the music is playing, you can dribble a drop of acetylcholine, a chemical messenger, on a neuron, and that once-depressive neuron will flip out. The way it perceives the world will have changed utterly.

As a scientist, Henry could observe that neuron at work. He had seen it with his own eyes: reality isn’t just out there; it’s created. Of course, a chair is a chair, but every person has a different view of the world. It’s completely subjective whether you perceive it as colorful or pale, bright or dark, happy or sad. Some people see colors more brightly when they’re angry; others perceive them as paler. Scientists have yet to understand why that is. All they know is that the objective world is a fantasy. Our coexistence is a muddle of interpretations. We see the world so differently.

Henry’s grandfather would probably have laughed out loud and said, “When your uncles drink whiskey, they also see the world differently.” Old age lets us see matters more calmly. But another of Henry’s revelations would have made his grandfather perk up. Looking into a microscope is a lot like beholding the night sky over the Kalahari. You see a universe of neurons and synapses. You delve into infinitude, you fly into space, surrounded by wild lights, and suddenly the stars start connecting with each other, spinning threads of light that allow them to communicate. When they have something to say to one another, a light flashes. The greatest fireworks light up all around you; the explosions spread through your brain like a swarm of birds. It’s a miracle, really.

And thanks to your help, Grandpa, thanks to your check, he would have said, I now know my way around that universe. I can read the landscape the way the bushmen read the Kalahari. When they stand on a mountain and look out over the savanna, they see things we can’t see: the future weather, the imminent dangers, a lion sitting a mile away. They see how everything is connected, the big picture. That’s how it is when I look through a microscope. I see something that no one else can. I can’t see the big picture quite yet. That’s still a long way off. His grandfather would have nodded and said, “You can do it.”

In expert circles, too, many people thought Henry could do it. His study of two neurotransmitters, and how they could help people focus, caused the scientific community to take note. Henry was invited to the United States by the National Institutes of Health (NIH), the world’s largest provider of research grants. After Henry spent a year in Washington, DC, Bert Sakmann brought him to Heidelberg. Under Sakmann, Henry developed his method for measuring how cells communicate with other cells. He won prizes, traveled the world, gave lectures. He was flying high. He seemed unbeatable. And then along came Kai.