Monday, October 03, 2005
Poison in the Ink: The Life and Times of Fridtjof Nansen
In 1906 Santiago Ramòn Y Cajal and Camillo Golgi shared the Nobel Prize in Physiology or Medicine for their contributions to neuroscience: Cajal for his contributing work that helped lay the foundation for the Neuron Doctrine, and Golgi for the development of his Golgi stain which was crucial for the work of so many neuroscientists, including Cajal. Unknown to most people however, is that a Norwegian zoologist named Fridtjof Nansen had declared the independence of the cellular nerve unit a year and a half earlier than Cajal, using the same Golgi stain employed by the Spanish histologist. When Cajal was just beginning to learn about the staining technique from a colleague, Nansen had already published a paper stressing the point.
On October 26, 1892, a crowd gathered for the christening of the Fram, a custom-built ship designed to take Fridtjof Nansen and his crew to the roof of the world. Four years had passed since Nansen had become the first European to cross the interior of Greenland, and he now hoped to win the race of becoming the first to reach the North Pole.
Among the guest present at the event was Gustaf Retzius, a colleague from Nansen’s early days as a neuroscientist. During a speech made at dinner that night, Nansen turned to Retzius and said that the field of neurobiology, like polar exploration, involved “penetrating unknown regions” and he hoped one day to return to it.
For all of his good intentions, Nansen never did return, and it would be something he would express regret over many times throughout his life. As he put it, after “…having once really set foot on the Arctic trail, and heard the ‘call of the wild’, the call of the ‘unknown regions’, [I] could not return to the microscope and the histology of the nervous system, much as I longed to do so.”
Those familiar with Nansen probably know him as an arctic explorer and as a world-famous diplomat who was awarded the Nobel Peace Prize in 1922 for his efforts to repatriate refugees after World War I.
But before the arctic expeditions and the humanitarian work, Nansen was a young zoologist interested in biology and the nervous system. He was one of the world’s first modern neuroscientist and one of the original defenders of the idea that the nervous system was not one large interconnected web, but instead was made up of individual cells that Wilheim Waldeyer would later call “neurons” in his famous 1891 Neuron Doctrine.
From a young age, Nansen was fascinated with nature; he loved its "wildness" and its "heavy melancholy" and he was happiest when he was outdoors. When it came time for Nansen to enter the University of Christiania (currently known as the University of Olso), he chose to major in zoology.
During his first year, Nansen answered a call from his department for someone to visit the arctic and collect specimens of marine life. In 1882, he set off for the east coast of Greenland aboard the sealing vessel Viking on a voyage that would last four and a half months.
The trip was a unique turning point in Nansen’s life. It provided him with his first glimpse of the Arctic and instilled in him the desire to cross Greenland’s icy interior.
“I saw mountains and glaciers, and a longing awoke in me, and vague plans revolved in my mind of exploring the unknown interior of that mysterious, ice-covered land,” Nansen wrote.
Upon his return, the 20-year-old Nansen was offered a post as the curator of the zoological department at the museum of Bergen. Nansen gladly accepted the position. His arctic dreams were put aside and the next six years were spent studying the invertebrate nervous system through a microscope.
One of the greatest difficulties Nansen faced in his research involved staining sections of nerve tissue. With the methods available at the time, the most that could be revealed of a neuron was its cell body, the proximal—and sometimes secondary—branch-like extensions of its dendrites and the initial segments of its thread-like axon.
At around this time, word was circulating that an Italian physician named Camillo Golgi had developed a new staining technique, one that stained only a few nerve cells in a section at a time, but which stained them so thoroughly that they were visible in their entirety.
After catching wind of the Golgi’s technique from a colleague, Nansen decided to pay the Italian doctor a visit. Despite arriving unannounced at Golgi’s lab in Pavia, Nansen was surprisingly well received and under the doctor’s careful tutelage, Nansen mastered what would become known as the Golgi stain in only a matter of days.
Upon his return, Nansen applied the Golgi stain to the nerve cells of a primitive fish-like animal called the lancelet. For the first time, Nansen could see clearly all the intricate branches of a neuron’s dendrites and could follow the entire length of an axon before it made contact with another neuron.
Armed with this new tool, Nansen began seeing things that couldn’t be explained by the reticular network theory, the reigning theory at the time for how nervous systems were organized. According to this theory, the nervous system was like a giant mesh net, with nerve impulses—whatever they might be—traveling unimpeded from one area to another.
One of Nansen’s objections to this view was based on a simple anatomical observation. The existences of unipolar neurons, or unipolar “ganglion” cells as they were known at the time, puzzled Nansen and lead him to ask a very logical question: How could unipolar neurons exist if nerve cells fused into one another as commonly believed, he asked. “How could direct combination between the cells be present where there are no processes to produce the combination?”
As their name suggests, unipolar neurons have a single primary trunk that divides into dendrites and an axon once away from the cell body. This is different from the image of neurons that most people are accustomed to, which show numerous dendrites branching off the cell body at one end and a long thread-like axon, terminating in tiny knobs at the other.
Other scientists attempted to explain away unipolar neurons by arguing that they were not very common. The closer the nervous system was examined, they said, the fewer unipolar neurons were found, especially in vertebrates like mammals and humans. Nansen remained unconvinced and pointed to the nervous systems of invertebrates like lobsters which have nervous systems made up almost entirely of unipolar neurons. To Nansen, this was strong evidence that the reticular network theory couldn’t be correct and in an 1887 paper, Nansen made the statement--bold at the time--that “a direct combination between the ganglion cells is…not acceptable.”
Nansen had his own theory about how nerve cells might combine. He proposed that it was in the ‘dotted-substance’ (what modern neuroscience calls “neuropil” in invertebrates and “gray matter” in vertebrates) that nerve cells communicated with one another. Nansen went even further, prophetically declaring that this ‘dotted-substance’ was the “principle seat of nervous activity” and “the true seat of the psyche.”
In the concluding paragraph of his 1887 paper, Nansen insisted that the dotted-substance will no doubt prove to play an essential role in whatever the final function of the nerve cells is determined to be. Unable to resist making one last speculation, Nansen also wrote the following:
“It is not impossible that [ganglion cells] may be the seat of memory. A small part of each irritation producing a reflex action, may on its way through the dotted substance be absorbed by some branches of the nervous processes of the ganglion cells, and can possibly in one way or another be stored up in the latter.”
In this, Nansen was especially farsighted, touching upon what modern neuroscience calls “neuroplasticity,” currently one of the most promising explanations to account for how simple reflexes can undergo modifications that last for minutes at a time and how learning can lead to behavioral changes that can last for a lifetime.
In the spring of 1888, Nansen presented a shortened version of his paper for PhD consideration to a review board in the ceremonial auditorium of Christiania University. In what was described as a heated presentation, Nansen reiterated his firm belief that nerve cells were not fused into a reticular network, that they were instead independent cellular units. Nansen’s conclusions were met with hostility by the review board’s members and he was accused of jumping the gun and getting ahead of his evidence.
Nansen was awarded his degree in the end, but not before one panel member expressed his firm conviction that Nansen’s hypothesis was destined to be forgotten like so many others.
The experience was a taxing one for Nansen. “In the end, there was such a confusion of one thing on top of another…that I believe that had it continued any longer I would have had a nervous breakdown,” he later wrote to a friend. “There was hardly a second to spare; we finished precisely as calculated, but no more.”
In this, Nansen wasn’t exaggerating. He was running out of time. Nansen was scheduled to depart four days after his PhD defense on a cross-country trek across the unexplored interior of Greenland. A long-time dream was finally coming true.
Nansen personally saw to every aspect of the trip. In a plan that critics called dangerous and foolhardy, Nansen proposed to cross Greenland from east to west. It would be a one-way ticket for himself and his team, with no chance of turning back.
“In this way one would burn one’s boats behind one,” Nansen wrote. “There would be no need to urge one’s men on, as the east coast would attract no one back, while in front would like the colonies on the west coast with the allurements and amenities of civilization.”
It took nearly two months, but in the end Nansen proved his critics wrong and his company of six became the first Europeans to cross the frozen island’s expansive interior.
The Greenland expedition gave Nansen his first taste of international fame. It sealed his reputation as an explorer and ended his career as a zoologist. Wanderlust had found its perfect victim, and soon Nansen was making plans to embark on another first.
For his next adventure, Nansen set his sights on becoming the first to circumnavigate the North Pole. In a highly criticized plan, Nansen proposed to freeze the in an ice flow and let it drift along a current that flowed from east to west across the Polar Sea.
But things didn’t turn out quite as Nansen had hoped, and the Fram did not drift close enough to the Pole. In a last ditch effort to salvage the mission, Nansen left the ship, determined to complete the journey on foot. He took with him only one other companion, Hjalmar Johansen, some sled dogs and enough supplies to last three months.
But the harsh conditions and uneven terrain proved to be more than the pair expected, and the two watched helplessly as their original three months stretched on for much longer.
“We built a stone hut, we shot bears and walrus, and for ten months we tasted nothing but bear meat,” Nansen wrote in his journal. “The hides of the walrus we used for the roof of our hut, and the blubber for fuel.”
In the end, a lack of supplies forced the two to turn back before they could reach the North Pole, but they held the record for Farthest North for five years until 1899.
The Fram voyage was Nansen’s last major expedition. As he grew older, Nansen became increasingly involved in politics, first becoming the Norwegian ambassador to London and then a high commissioner for the newly formed League of Nations. From 1919 until his death in 1930, Nansen was a devoted global humanitarian. In 1920, when nations were still trying to rebuild Europe after the devastation of World War I, Nansen was dispatched by the international organization to direct the repatriation of half a million prisoners of war who had not yet been exchanged. Afterwards, Nansen successfully raised funds for famine relief efforts in Russia on behalf of the Red Cross.
For his success in these two tasks, Nansen was awarded the Nobel Peace Prize in 1922. When presenting him with the award, the Chairman of the Nobel Committee had these words to say about Nansen: “Perhaps what has most impressed all of us is his ability to stake his life time and time again on a single idea, on one thought, and to inspire others to follow him.”
The reference was to Nansen’s humanitarian work, but the same sentiment could have just as easily been applied to his numerous other undertakings. Whether he was navigating uncharted landscapes of ice, introducing compassion to the realm of politics, or defending an unpopular view of the nervous system, Nansen readily staked his reputation and often his life on his beliefs. Any of these tasks could have easily occupied a person for a lifetime, but Nansen tackled each unknown with fresh enthusiasm, and was rewarded in many cases with success.
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