December 13, 2011 4:18
This may seem surprising to most of us, but it has puzzled neuroscientists for decades. Given that the brain is the most potent known computing devices, it becomes an important question as it can function as effectively?
A long-standing hypothesis is that the brain is extremely reliable and variativen because he is involved in many tasks simultaneously, which affect each other.
That this assumption is directly tested by researchers from UCL. Team — collaboration researchers from Wolfson Institute for Biomedical Research and a theorist, Peter Latham of the Gatsby Computational Neuroscience Unit — drew inspiration from the famous butterfly effect, which says that the flap of a butterfly wing in Brazil can cause a tornado in Texas.
Their idea was the introduction of small perturbations to the brain, nervous equivalent of butterfly wings, and monitoring of follow-up. Will the growing resentment and indirect effect, thus affecting the rest of the brain, or immediately die out?
It turned out that there is a huge domino effect. The perturbation was a single extra 'peak', or nerve impulse, submitted to a single neuron in the brain of rats. This one additional surge caused approximately 30 new additional peaks in the surrounding neurons in the brain, most of which caused another 30 additional peaks, and so on. It may not seem like much, given that the brain produces millions of peaks per second. However, researchers have found that in the end, one additional spike affected millions of neurons in the brain. "This result indicates that the variability we observe vmozgu can actually be due to noise, and is a major feature of the normal function the brain, "said lead author Dr. Mickey London, of the UCL.
Such a rapid increase of the peaks means that the brain is extremely 'noisy', much noisier than computers. However, the brain can perform very complicated tasks with enormous speed and accuracy, far faster and more accurate than the most powerful computer ever built (and probably built in the foreseeable future). UCL researchers believe that the brain to ensure proper performance in a high noise level, you must use a strategy called "high-speed code." In high-speed code, the activity of groups of neurons read many neurons, and ignore the individual variability, or noise, produced by each of them.
We now know that the brain is really noisy, but we still do not know why. UCL researchers suggest that this is the price for the communication between neurons (each neuron connects with 10,000 others, resulting in more than 8 million kilometers connections in the human brain). It can be assumed that a powerful connection, at least in part responsible for the computational power of the brain. However, studies show that the more powerful the connection — the more noise. Therefore, although the noise and can not be a useful feature, but at least it is a by-product of brain activity.