Hot on the Neuro Trail

Scientists are struggling to build a comprehensive theory of how the brain works, with one team working on a computer simulation of a billion nerve cells and the connections between them.

When Prof. Moshe Bar contacted a publisher to propose a book, the first thing he was asked was whether he intended to publish yet another work entitled “How the Brain Works.”

That was not his intention, but the editor’s barb was apt: A  quick search of the website brings up an unreasonable number of titles that are variations on this question-cum-promise. Most of them do not deliver the goods, says Bar, , head of the Gonda Multidisciplinary Brain Research Center at Bar-Ilan University. Their authors are mostly not theoreticists, he explains.

In fact, only a few scientists are currently trying to develop comprehensive theories of brain functions. In recent decades there has been tremendous progress in the study of the building blocks of the brain − nerve cells, the way electrical signals are produced in the various cells and the chemical and electrical connections between them. However, the understanding of their collective activity − the sociology of nerve cells, so to speak − still remains a mystery.

“You have to remember that brain research is a new field in scientific terms, but I would like to think that some day there will be a basis for a comprehensive theory,” says Bar. “Just as in physics there are [James Clerk] Maxwell and [Isaac] Newton and [Albert] Einstein, we too need principles that will encompass a wide variety of cerebral phenomena. This is our holy grail, and we will get there.”

Scientists are making an effort to crack the connection between human behavior and consciousness, on the one hand, and neural activity, on the other, but the research is only in its initial stages. Researchers are now daring to declare that given perfect documentation of all the electrical activity in the brain it would be possible, theoretically, to give a full description of human experience and behavior. However, while the scientists see the brain’s electrical signals as the definite language of neural activity, they are far from understanding how to decipher this secret language, due to its tremendous complexity.

‘Local’ connections

The human brain has 1 billion nerve cells ‏(by comparison, the Milky Way, our galaxy, has 100 billion to 200 billion stars‏), each of which is connected to ten thousand other nerve cells. At a crude estimate, there are about 1,000 trillion ‏(that’s 1,000,000,000,000,000‏) connections between nerve cells in the brain. Scientists today are focusing on finding how electrical activity in specific areas of the brain affects various mental abilities and phenomena.

“We are far from having a comprehensive theory of the brain. This is fully expected, given the enormous unparalleled complexity of the problem,” says Hebrew University Prof. Haim Sompolinsky, one of the world’s leading brain theoreticians. “Furthermore, whereas in the past one could freely speculate about the subject, the enormous amount of accumulated data about the structure and function of the brain puts important constraints on a theory of the brain.

Such speculation is no longer acceptable without the data being taken into account. At the same time, we are witnessing impressive progress in understanding specific, “local” questions, which  deal with an important part of brain function, so that the theorists’ work has never been more exciting.” A great deal of important work has been done on mapping specific cognitive phenomena, the neural activity at their base, and their relationship to other phenomena.

But on another front, scientists are trying to arrive at a comprehensive breakthrough using unprecedented technological means. South African-born researcher Henry Markram of the Ecole Polytechnique Federale de Lausanne, in Switzerland, is currently trying to set up the largest ever initiative in brain research. Called the Human Brain Project, its aim is to create a full computer simulation of all the nerve cells in the human brain and all the connections between them. Markram claims that such a simulation will enable the decoding of basic mechanisms in the brain and the discovery of essential remedies to brain diseases within 30 years.

Markram is competing with five other groups for a billion-euro grant from the European Union. Prof. Idan Segev of the Interdisciplinary Center for Neural Computation at the Hebrew University of Jerusalem, who is a partner in Markram’s initiative, says that the final proposal for the competition will be submitted at the beginning of October.

Opposition to Markram

Within the ranks of the brain research community, there is considerable opposition to the prospect of Markram winning the competition; a group of researchers has even resigned from the initiative.

Critics fear the initiative will attract funds at the expense of other brain studies, fail to fulfill its great promise and damage the reputation of the field. Moreover, they have questioned the project’s scientific approach. The basic principle of Markram’s initiative is that research insights will be achieved through the creation of a detailed model of all the neural connections in the entire brain. Many critics say it is more important, and immeasurably less costly, to invest first in developing theories that would aid research and focus it.

Markram’s project “sounds attractive,” says Bar, “but it’s rather naive to think that if you build a big and precise model, an idea will emerge from this for understanding the brain as a whole. I don’t think it’s proportional to the promise and the funding, and it won’t solve the problem of understanding the brain.”
Beyond that, he says, an initiative of such magnitude must be based on prior theoretical breakthrough, which do not exist at the moment. “We don’t need a paradigm shift, but rather some sort of comprehensive paradigm to begin with”
Segev holds the opposite view. “On the one hand, I agree that the great understanding will come from high-level observations, principles rather than specifics, but there is also frustration in the theory in a certain sense because thus far there hasn’t been any breakthrough in brain research of the sort made by Einstein. There are captivating ideas but there are no major breakthroughs.”

Segev adds that Markram’s project will also include the organization of the research findings in a large database, which in itself is necessary for advancing research. He rejects the argument that the project risks harming brain research funding for others. “Money for research attracts more money for research − from sources that in the past hadn’t contributed to this field. In fact, I am in favor of megalomania of the right sort: The 21st century is characterized by megalomaniac projects of the sort Markram is proposing,” adds Segev.

“The big breakthrough isn’t going to come from the lone scientist, but rather from international cooperation in understanding the brain, like the particle accelerator in Switzerland,” continues Segev. “I understand the reservations, both those regarding principle and those regarding practicalities, and that the conservative scientists are worried about the megalomania evinced by Markram, a type who thinks he knows what is right. But they too think they know what is right, so maybe they have to let others make the mistakes and go with the flow. I am in favor of big flow, which will without a doubt bring about a dramatic breakthrough in brain research.”