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Lauren Admire | 12 Jul 2010 17:00

The Brain Is a Noisy Place

The human brain is capable of processing 100 trillion calculations per second, the equivalent of 100 teraflops of information. That is a lot of information to process, and some firing neurons may just be carrying messages that are, well, a tad bit unnecessary. Science calls this "noise," random brain activity that doesn't have any important function, but have now found that this noise might be making your brain unreliable.

The perennial conundrum facing scientists was how the brain could be so reliable when its circuitry was so variable. The prevailing hypothesis claimed that the circuitry itself is reliable, but because the brain is engaged in so many different tasks at any given moment, there appears to be a high variability in outcomes.

Researchers at UCL tested this hypothesis, using a modern-day, laymen's scenario: If a butterfly's wings flapped in one area of the brain, could it cause a tornado in another area? Researchers introduced a nerve pulse into a single neuron of a rat's brain. As expected, the single pulse raced across other neurons and activated them - much like a line of dominos falling one after another. The pulse triggered about 30 other neurons, and each of those neurons triggered 30 more, eventually leading to a possible total of a few million of neurons affected by a single, involuntary pulse.

"This result indicate that the variability we see in the brain may actually be due to noise, and represents a fundamental feature of normal brain function," states lead author Dr. Mickey London, from the Wolfson Institute for Biomedical Research.

This means that the brain is far noisier than any known computer, and yet still more accurate and faster than any known computer built. How does the brain do it? The researchers believe that human brains use a strategy called "rate code," where neurons pay more attention to similar messages from multiple neurons, but ignore their individual "noises."

Source: Science Daily

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