For many years, neuroscience has used different tools to try to “listen” to the conversations of neurons. In the same way that linguists decipher an unknown language, scientists try to decode the patterns of neural firing to try to find out the grammar of the brain. In these attempts, it seems that new stars have been born: the dendrites.
The latest research seems to be showing that neuroscience, in terms of estimating the capacity of our brain, has only been scratching the surface. The University of UCLA discovered a hidden layer of neuronal communication through the dendrites. This means that the capacity of the brain could be up to 100 times greater than previously thought.
This discovery can significantly change the foundations of conventional neuroscience. Until a few months ago the foundations of neuroscience were supported in the belief that dendrites were something like passive wiring that carried electrical signals to the neural body, the soma. But this research showed that dendrites are much more than just passive drivers. The dendrites generate their electrical signals, in peaks five times bigger and more frequent than the peaks that come from the nuclei of the neurons.
What does this discovery entail?
We are talking about a very radical change in the knowledge that neuroscience has about the functioning of the brain. Among other things, it is possible that learning processes occur at the level of the dendrites and not in the soma of the neurons.
Conventional neuroscience has argued that the electrical signals emitted by cell bodies are the basis of our cognitive abilities. We now know that dendrites do not have a passive function and that they also emit their own electrical signals.
If this is not already surprising by itself, the researchers found that dendrites are also intelligent. They are able to adapt their electric shot over time. This type of plasticity has only been observed so far in neuronal bodies. This suggests that the dendrites could learn by themselves.
Because dendrites are much more active than the cell body, we can begin to intuit that much of the information generated in a neuron is made at the level of dendrites without their being reported to the cell body. That is, the dendrites can act as a computing unit and process their information. An independence that a few months ago was not even suspected.
“It’s like suddenly discovering that the cables that lead to your computer’s CPU can also process information, completely extravagant and somewhat controversial.”
-Dr. Mayank R. Mehta, director of the research-
The capacity of the brain: research
Dr. Mayank R. Mehta’s research team devised a system that allows placing electrodes near the rat dendrites. This system allows you to capture electrical signals from the animal during the time you are awake and performing your daily activities, as well as during sleep. In this way they were able to listen for four consecutive days to the electrical activity of the dendrites and transmit it live to the computers.
The electrodes were implanted in the area of the brain linked to the planning of movements, the posterior parietal cortex. What they managed to capture was that during the sleep periods the electrical signals seemed like irregular waves, and with each one a peak was pointed out.
That is to say, while the rats slept, the dendrites chatted among themselves, and they did it in electric shots up to five times faster than those originated in the cell bodies. During the waking periods the firing rate was multiplied by ten.
The dendrites: measurers of the here and now
Another shocking discovery during this investigation was found in the type of signal emitted by the dendrites. The electrical signals of the dendrites could be digital, but they also showed large fluctuations, almost twice as large as the spines themselves. This type of wide range fluctuation shows that the dendrite also showed computer activity. Something that had not been seen before in any pattern of neuronal activity.
What calculates this type of emission of the dendrite seems to be related to time and space. Observing the rats behaving in a labyrinth, two types of signals were distinguished. One in the form of peaks from the cell body in anticipation of a behavior. In this case it was before turning a corner. While the dendrites issued their calculation signals just when the animal turned the corner.