Brain Cells and Democracy
Written by Lewis D. Eigen
There is new scientific evidence that indicates that some of the cells of the brain are organized according to democratic principles.
It is common for science to inform and provide a framework for politics. It is very rare for political concepts to be useful in understanding something in science. But it appears that there may be one dramatic example thanks to some pioneering neurobiological research in Israel.
The human brain is made up of about 100 billion nerve cells which we call neurons. Those neurons “communicate” with other cells by sending tiny electric currents. These in turn produce chemical reactions at the synapses which are between the cells. The chemicals then stimulate further electrical signals. Any animal brain is an electro-chemical “fireworks” display of activity. We also know that the neurons in different parts of the brain relate to and control different bodily functions. The most common example is the person who has a stroke and brain cells are damaged in the left side of the brain, the right side arm or leg might become partially of totally dysfunctional. Physicians call this “hemiplagia.”
Brains do not have single cells that control single functions. Neurons seem to be partially redundant. If only a few cells are damaged in an area, the other cells can “carry on.” This makes evolutionary sense, as functions might be very short lived if they depended on a single cell. So groups of about 10,000 interconnected neurons—networks—somehow perform different functions.
Ever since scientists have learned about the groups of cells, they asked the natural question: How are these cells organized? For example, is there one “Chief Cell” in the cluster that controls the others. Does each cell in a cluster communicate with the Chief Cell and the Chief with the lower cell? If so, do the “underling” cells communicate also with each other? Or is there another form of organization? For example, there could be a few neurons that do the acting, and the others are standbys to take their place if one dies or is disabled. In some sharks, there were many teeth in the jaw structure and behind each one are a number of “spares.” If a tooth is broken, the next moves into place and performs the function.
To make a political analogy, the first model with a Chief Cell is like a monarchy. The second, is an oligarchy. However, through some very clever research, Dr. Elad Schneidman and Ronen Segev in Israel have demonstrated that the neurons of the retina of the salamander operates in what I call a democratic mode.
The Israeli researchers have studied neuron clusters of about 100 cells at a time. What they wanted to do was just a year or two ago thought impossible. They designed a method of observing the activity of each of the cells and it’s interaction with every one of the other 99 neurons in the network, They, and other scientists, have long been puzzled about the fact that when there is communication between two cells in a network, it is weak and sometimes unreliable. The function of the cells in an eye retina is to determine whether there is a light pattern present and in some animals discern color. But the cells do not always “agree.” Under a particular stimulation, many of the cells in a cluster will react similarly but others may not. Even a single neuron will sometimes give different signals in response to the same stimulus.
What the researchers observed was that when a particular visual stimulus is presented to the small cluster of the larger network, all 100 of the neuron cells participate, but they do not all agree. Under the further stimulus of each of the neurons “observing” a visual stimulus, the cells of the cluster interact and “influence” each other. Dr. Schneidman of the Weismann Institute of Science has described the situation by making an analogy:
“It’s like peer pressure. One opinion doesn’t carry much sway, but the joint effort of many weak signals together can control the group as a whole.”
The evolutionary advantage to such an organization of cells is the “wisdom of the crowd”. Going with the perception and signals of any single cell makes the whole organism potentially dependent on a single cell. And if that cell is defective or has a period of error, all the cells will suffer the consequence.
There is alternative way, similar to Schneidmann’s, of viewing the neural network as organized in political organizational principles. This is analogous to the subjects of the kingdom suffering for the poor policies and decisions made by the king. The entire crowd participating in each decision has the advantage over the oligarchy that the aristocrats may all perceive something one way and different from the majority of the ordinary citizens. The majority might be wrong on a given occasion, but arguably over time, such a democratic organization of neurons can be far superior to other, non democratic models, where the decision is dependent on fewer cells. This superior democratic organization of cells in the brain’s of living animals may be one of the reasons that those animals have survived when so many more animals have gone extinct. However, it is entirely possible that dinosaur and many other extinct animals also had this democratic cell organization in part and different forms of cell organization were only of the far distant past.
The Israeli research that demonstrated what we can think of as democratic cell organization was conducted with clusters up to 100 cells. Why not the 10,000 that make up a typical brain network? The reason is that the Israeli researchers are observing each of the individual neurons and its reaction with every other neuron in the cluster. If the same kind of analysis were done for all 10,000 neurons of a typical network, there would be more observations needed than there are stars in the entire universe—1030 to be precise. (That is 10 followed by 30 zeros.) The whole network is just too large for studying all the interactions with the scientific tools at our command, It was a great break through for the analyses of the approximately 10,000 neural interactions possible with a sample cluster of only 100.
The typical modern animal has many billions of cells, indeed billions of clusters—neural networks. Is the identified cluster of 100 cells of the salamander retina the complete cluster of cells that perform the same function? Almost certainly not. The total democratic cluster for the retina perception likely involves a much larger cluster. It’s as if we studied a New England town, operating on the traditional town meeting, direct democracy model, and we only measured the people in the South West quadrant of the town. We know how they voted (some for and some against), and we see the laws that are passed by the whole town. We can determine how they communicate with each other, but not what they do or, even whether or not they communicate with citizens in the rest of the town. Intuitively we are almost certain that they do, and we also intuit that any cluster of 100 cells that the Israeli scientists pick, interact electrically and chemically with other cells—not necessarily all other cells but others almost certainly. So an immediate question is, how many cells are there in the entire cluster of the salamander retina? In political terms, how big is the community political entity? Then of course we would want to know about the other political entities (the ones that control other functions), Are the different cell communities of the brain roughly the same size—like properly apportioned congressional districts, or are they like our gerrymandered districts? Is dual citizenship allowed? Can one neuron be part of the retina community and also part of another functioning community? Are all communities, in the same animal, democratic or just some? What, if any, are the physical differences of cells of one functional community as opposed to the cells of another? Can citizens change citizenship?
The Israeli research illustrates that the political model is a useful one to help ask good scientific questions, since most scientists in modern democracies are familiar with the political structures and questions about them. For the most part science and politics are estranged in our society. If nothing else, it is pleasant to view an example where the two perspectives might be mutually supporting—that is a very rare occasion in today’s world.