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The brain has more computational capacity than previously thought, according to UCLA researchers:
Dendrites have been considered simple passive conduits of signals. But by working with animals that were moving around freely, the UCLA team showed that dendrites are in fact electrically active — generating nearly 10 times more spikes than the soma (neuron cell body). The finding, reported [DOI: 10.1126/science.aaj1497] [DX] in the March 9 issue of the journal Science, challenges the long-held belief that spikes in the soma are the primary way in which perception, learning and memory formation occur.
"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. This is a major departure from what neuroscientists have believed for about 60 years," said Mehta, a UCLA professor of physics and astronomy, of neurology and of neurobiology.
Because the dendrites are nearly 100 times larger in volume than the neuronal centers, Mehta said, the large number of dendritic spikes taking place could mean that the brain has more than 100 times the computational capacity than was previously thought.
Is that your final answer?
(Score: 0) by Anonymous Coward on Wednesday March 15 2017, @06:06PM
This kind of article is usually pretty bad. All of the commentary about what this means is just conjecture meant to catch your eye. This isn't going to change artificial brain design because nobody is designing brains at this level of detail. State-of-the-art neural nets don't have stateful neurons, so the only relevance this has to them is in the synaptic weights, which they already cover. Same goes for the computational cost: the cost has always been at the synapse, which is where the dendrites get their inputs.
The analog/digital commentary doesn't really mean anything either.
What they are saying is the soma was thought to be responsible for determining an action potential (neuron firing) after being stimulated by inputs from the dendrites, but this research suggests that a dendrite could alone cause the action potential without involving the soma. Without reading the paper I can only guess at how that's meant to happen (or in what sense it's true) since the soma is effectively between the dendrites and the axon. On the other hand, a lot of stuff goes on in the soma during an AP, and bypassing that activity could have a significant impact on its state.