Artificial Intelligence, Science, Technology
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Why our brains may be 100 times more powerful than believed

dendrites-2
The dendrites in our brain have been underestimated for 60 years says a new study (Credit:vitstudio/Depositphotos)

A new study out of the University of California Los Angeles (UCLA) has found that one part of the neurons in our brains is more active than previously revealed. The finding implies that our brains are both analog and digital computers and could lead to better ways to treat neurological disorders.

The focus of the study was the dendrites, long branch-like structures that attach to a roundish body called the soma to form neurons. It was previously believed that dendrites were nothing more than conduits that sent spikes of electrical activity generated in the soma to other neurons. But the study has shown that the dendrites themselves are highly active, sending spikes of their own at a rate 10 times that previously believed.

The finding runs counter to the long-held belief that somatic spikes were the main way we learn and form memories and perceptions.

“Dendrites make up more than 90 percent of neural tissue,” said UCLA neurophysicist Mayank Mehta, the study’s senior author. “Knowing they are much more active than the soma fundamentally changes the nature of our understanding of how the brain computes information. It may pave the way for understanding and treating neurological disorders, and for developing brain-like computers.”

The researchers also found that unlike the spikes of electrical activity generated by the somas, the dendrites could put out longer-lasting voltages that in their sum total were actually more powerful than the somatic spikes. They say the spikes are like digital computing in that they are all-or-nothing events, while the dendritic flows are akin to analog computing.

“We found that dendrites are hybrids that do both analog and digital computations, which are therefore fundamentally different from purely digital computers, but somewhat similar to quantum computers that are analog,” said Mehta. “A fundamental belief in neuroscience has been that neurons are digital devices. They either generate a spike or not. These results show that the dendrites do not behave purely like a digital device. Dendrites do generate digital, all-or-none spikes, but they also show large analog fluctuations that are not all or none. This is a major departure from what neuroscientists have believed for about 60 years.”

Mehta adds that the fact that dendrites are about 100 times larger in volume than somas, it’s possible that our brains have 100 times more capacity to compute information than previously believed.

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A neuron with the dendrites shown in green (Credit: Shelly Halpain/UC San Diego)

In making their discovery, the UCLA team was able to implant electrodes in the brains of rats that went next to dendrites. This was a departure from previous work where the sensors went straight into the dendrites, killing them and making their activity impossible to measure. They found that the dendrites were five times more active than the somas when the rats were sleeping, and 10 times more active when they were awake and moving about.

The discovery shows that learning likely takes place with more flexibility than previously believed.

“Many prior models assume that learning occurs when the cell bodies of two neurons are active at the same time,” said Jason Moore, a UCLA postdoctoral researcher and the study’s first author. “Our findings indicate that learning may take place when the input neuron is active at the same time that a dendrite is active — and it could be that different parts of dendrites will be active at different times, which would suggest a lot more flexibility in how learning can occur within a single neuron.”

“Due to technological difficulties, research in brain function has largely focused on the cell body,” added Mehta. “But we have discovered the secret lives of neurons, especially in the extensive neuronal branches. Our results substantially change our understanding of how neurons compute.”

The research has been published in the journal Science.

Source: UCLA

Link to article: http://newatlas.com/brains-more-powerful/48357/

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I made my bones as an advertising copywriter. My TV, radio and print ads have amused millions of people and helped sell tons of cleaning products, coffee, macadamia nuts and other goodies. But I prefer that other kind of fiction: short stories and novels. My first published novel, Mindclone, is a near-future look at the amusing and serious consequences of brain-uploading. It’s garnered mostly five star reviews. The sequel is percolating in my brain even now. Stay tuned.

2 Comments

  1. Hi Dave, I read this article when it first came out. It may be true but I I think I will wait until it is is verified by other institutions. It doesn’t make a lot of sense that others haven’t noticed this activity and it may be due to lateral pickup from the probes they are using in living systems. I may also be due to neighboring glial cells that are changing the environment (eg. calcium ion level) since they are noted to produce waves of activity in neighboring neurons and from glial cell to glial cell. Some of this could be easily confused with dendritic computational activity.

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  2. A neuron’s dendrites link right into its soma, the neuron body. Since there is no reason for a neuron to randomly send signals into itself, I think what is happening is that dendrites react to the inputs that they receive from the neurons that link to them by either magnifying or inhibiting their charges. Multiple neurons may link their axon branches to multiple dendrites of a single receiving neuron. The purpose of dendritic activity may be to modify inputs to the soma based on the “meaning” of the particular neurons that link to it.

    In the artificial neural network (ANN) I am developing, it is important to modify charges that are sent and received. The ANN’s modulation function modifies charges when they are sent to another neuron, and an integration function modifies charges when they are received by a neuron. Dendritic activity would implement the integration function in the biological neuron.

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