A group of scientists from the University of California at Los Angeles, conducting another study, stumbled upon facts indicating that some of the neurons in the human brain are much more active than previously thought. The center of the research was the dendrites, nerve cell outgrowths resembling tree branches, growing out of the central part of the neuron, the so-called soma. Previously, it was thought that dendrites were only the conductors by which electrical impulses formed in the soma were transmitted to other neurons. However, new research has shown that the dendrites themselves are active parts of the nerve cell, they are able to produce their own impulses, the intensity of which is 10 times greater than the intensity of somatic nerve impulses.
This discovery contradicts the traditional view that it is the somatic impulses that are the main activity that shapes memory and is responsible for perception. “Dendrites account for about 90 percent of all nerve tissue,” says Mayank Mehta, a neuroscientist at the University of California, “The fact that dendrites are more active than soma fundamentally changes everything we know about information processing and storage in the brain. And further research in this direction should give us a greater understanding of the nature of certain neurological disorders and mental illnesses. Moreover, such information will be extremely useful for building computers that work like the human brain.
Among other things, the researchers found that dendrites are capable of producing electrical pulses of longer duration and greater voltage than the soma. In terms of signal processing, the pulses produced by dendrites are more like analog signals, while somatic pulses are somewhat akin to the digital pulse signals that run through the circuits of electronic chips.
“We have found that dendrites are hybrids capable of making both analog and digital calculations. In this they are more similar to elements of quantum computers, which can be seen as elements of analog-digital information processing,” says Mayank Mehta, “One of the fundamental principles of neurobiology held for 60 years was that neurons in general are purely ‘digital devices.’ However, we have proved that dendrites behave in a slightly different way, there is of course a “digital” component to their activity, but the signals they produce also have analog vibrations. And we still do not know which of these parts plays the main role in brain activity.
All of the above points to the fact that the “computing power” of our brain can be a hundred times greater than previously thought, because the total volume of dendrites is the same hundred times greater than the total volume of the neuron soma.
In their research, California scientists used electrodes embedded in the brains of experimental animals. The electrodes were placed so that they passed very close to the dendrites, which made it possible to measure their activity level and other parameters. It should be noted that in previous similar studies, scientists tried to introduce electrodes directly into the dendrites, which apparently killed them and made it impossible to perform any measurements. Using signals from the electrodes, the scientists found that the dendrites were five times more active than the soma during sleep, and ten times more active when the test animal was awake.
“Due to the many technological challenges, previous research on brain function has focused on studies of the nerve cell body, the soma,” says Mayank Mehta, “We were able to look at the ‘secret’ aspects of neuronal life, and these aspects will fundamentally change everything we know about nerve cell function and the brain in general.”
