New research can lead to a better understanding of how the brain works - and may lead to new approaches to the treatment of neurological disorders and the development of computers that think more like humans
Scientists from the University of California at Los Angeles - UCLA discovered that dendrites (shown here in green) are not just passive conduits for electrical currents between nerve cells in the brain. Photo: Shelley Halpain / UC San Diego
A new study by researchers at the University of California at Los Angeles - UCLA may change the understanding of how the brain works, and may lead to new approaches to treating neurological disorders to develop computers that think more like humans.
The research focused on the structure and function of dendrites, which are components of the neurons, the nerve cells in the brain. Neurons are large tree-like structures composed of a trunk (called soma - the body of the nerve cell), branches and many sections called dendrites.
The nerve cell bodies generate short electrical pulses called spikes to connect and communicate with each other. The scientists believed that these somatic pulses normally activate the dendrites, which passively send currents to the somas of other neurons, but this process has not yet been directly tested. This process is the basis for the formation and storage of memories. The scientists believed that this was the main function of the dendrites.
The researchers discovered that the dendrites are not just passive tubes. Their research showed that the dendrites move freely and produce almost 10 times more pulses than the neuron cell body. This finding challenges the belief that the main way in which perception, learning and the creation of memories are formed is in the body of the nerve cell.
"Dendrites make up more than 90 percent of neural tissue," says UCLA neuroscientist Mayank Mehta, lead author of the study. "Knowing that they are much more active than the cell body fundamentally changes the nature of our understanding of how the brain computes information. This may pave the way for the understanding and treatment of neurological problems, and for the development of brain-like computers."
The researchers also discovered that dendrites produce large voltage fluctuations in addition to nerve impulses. The neural impulses are binary, all or nothing events. Neuron cell bodies work like digital computers. However, in the dendrites, apart from these impulses, a slowly changing voltage is created, with an even greater intensity than the impulses, which leads the researchers to assume that the dendrites perform an analog calculation.
"We found that dendrites are hybrids that do analog and digital calculations, so they are essentially different from purely digital computers, but somewhat similar to quantum computers that are also analog," said Mehta, "a basic belief in neuroscience is that neurons are digital machines. Either they create impulses or they don't. These results show that dendrites produce not only impulses but also large analog oscillations that are all or nothing, a major departure from what neuroscientists have believed for the past sixty years."
The study was published in the March 9 issue of the journal Science.
https://www.sciencedaily.com/releases/2017/03/170309150634.htm
18 תגובות
Miracles,
According to the quote you gave, you seem to be right.
rival
My source is a 1700 page book called Principles of Neural Science, published by McGraw-Hill.
But, on Wikipedia, https://en.wikipedia.org/wiki/Neuron I am qouting:
The cell body of a neuron frequently gives rise to multiple dendrites, but never to more than one axon, although the axon may branch hundreds of times before it terminates. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: for example, neurons can lack dendrites, or have no axon, and synapses can connect an axon to another axon or a dendrite to another dendrite.
Miracles,
So from your answer I understand that the answer is positive and there are neurons in our body that are not in the brain. This is quite surprising because until today I have always treated a neuron as an organ found only in the brain even if it has extensions that reach, for example, the spine, I did not think that there were neurons found in the hip, for example.
Regarding neurons without an axon, I did a Google search and the results actually said that there are no neurons without an axon. Could you perhaps give a link to the place where you read that there are such neurons?
rival
There are neurons in which a dendrite serves as an axon. I don't know specifically which cells are like that.
Example: there are sensory neurons that connect the knee to the lower spine - and from there there are motor neurons back to the knee. This is what is tested when you give a light blow with a rubber hammer to the knee. There are other such reflexes in the body.
Miracles,
I did not understand from your explanation, are there neurons that are not located in the head? That is, those whose parts, the cell body, the dendrites and the axon are all located in the hand, for example? Or on foot?
And what is the function of a neuron without an axon? where is it located
rival
There are broadly three types of neurons. One type connects to sensory cells, the second type to motor cells and the third type only connects to other nerve cells.
The nerves are nothing but a "rope" of a large number of nerve cells. There are several nerves in the head (12 pairs), and more nerves that go from the spine to the organs of the body.
And I checked myself again - indeed there are neurons without an axon 🙂
And are there neurons located outside the brain? Or outside the head area? After all, a neuron is a nerve cell and these are also located in the spine, in the hands, in the legs... In my connotation, a neuron has always only referred to the brain.
rival
Right...my mistake.
Miracles,
It doesn't make sense to me either, but first you said: "I assume that the axon is not stained, or that what is shown is a neuron without an axon."
rival
A neuron is a cell that processes and distributes information. A cell without an axon is not a neuron.
Miracles,
Are there neurons without an axon? in the brain? What is their role?
An interesting topic is the determinism in which some scientists or philosophers (not all of course) from different fields of science have made unequivocal assertions about the brain and human nature for example
Regarding free will there is/isn't there and regarding the subjective feeling, is it just a type of allusion, is it possible to implement a creature with a subjective feeling in another material and all kinds of rigid determinations
While actually things so central to the way the brain works in general were not yet known to science, if something so central to the brain that is now found was not known until now, the question arises, are there more layers that will be found in the future?
It's not some small addition, what they found is something very significant,
Apparently it seems that there should be a degree of humility even for a brilliant and excellent person in a certain field from trying to generalize his perception
About another system that is actually not fully recognized, it can be said that if this system works in a certain way
that it corresponds to the field in which the person is knowledgeable, so for example there will be a free choice or not according to his understanding, but only on the assumption that it only works in those fields, but since there is still a lot to understand about this system, there should be a degree of caution,
Like a hammer every problem looks like a nail, once upon a time in the steam era some people perceived man as such a machine
Biology with cogwheels Today, in the era of the classic computer, the brain is seen as a digital biological computer,
It is now clear that this is a much greater level of complication, a combination of analog and classical computing, and the question is whether there are other layers that might also hide a non-classical calculation system as some scientists believe and others deeply disdain this possibility? Apparently it seems that you do not fully know something, you should be careful not to make unequivocal statements about it.
It makes sense that all the actions of the brain are carried out in the very connections between the dendrites.
Since the brain does not have a central processor like a computer, this means that each such dendrite or its connection with another dendrite is actually both a processor and a memory store and probably works in an analog way, and receives an analog value that it passes on otherwise it would not be able to store information beyond zero or one, the stimulus The nerve that flows along the axons should also be an analog value...
rival
In the original article it is stated that what is painted in green are dendrites. I assume that the axon is not colored, or that what is shown is a neuron without an axon.
The thick green artery that goes out towards the left and down in the picture.
1. In my opinion, the main artery painted in green in the picture is an axon and not a dendrite.
2. "This finding challenges the belief that the main way in which perception, learning and the creation of memories are formed is in the body of the nerve cell"
Strange, according to what I know, the main part of learning and the creation of memories are created in synapses that are scattered en masse on the dendritic branches.
3. "The researchers also discovered that dendrites produce large voltage fluctuations in addition to nerve impulses. The neural impulses are binary, all or nothing events. Neuron cell bodies work like digital computers. However, in dendrites, apart from these impulses, there is also a voltage that changes slowly, with a strength even greater than that of the impulses.
It's really strange that until today they haven't discovered this, after all neuroscientists are constantly measuring the voltage intensity of the electrical pulses in the brain, if these pulses ride on top of a changing analog voltage then they themselves should also have changed, how come they didn't recognize this with all the measuring devices?
To: Y. Forat
You were right in your comment. "The brain is ten times more active" should be written. but,
It was possible with a slightly different wording "ten times more brain activity"
Ten times, not ten times