PITTSBURGHMuch like snowflakes, no two neurons are exactly alike. But it's not the size or shape that sets one neuron apart from another, it's the way it responds to incoming stimuli. Carnegie Mellon University researchers have discovered that this diversity is critical to overall brain function and essential in how neurons process complex stimuli and code information. The researchers published their findings, the first to examine the function of neuron diversity, online in Nature Neuroscience.
"I think neuroscientists have, at an intuitive level, recognized the variability between neurons, but we swept it under the rug because we didn't consider that diversity could be a feature. Rather, we looked at it as a fundamental reflection of the imprecision of biology," said Nathan N. Urban, professor and head of CMU's Department of Biological Sciences. "We wanted to reconsider that notion. Perhaps this diversity is important maybe it serves some function."
Estimates say that the human brain alone has upwards of 100 billion neurons, which can be broken down into a number of different types. While members of the same type look structurally alike, and, as a group, contribute to completing the same overall task, each individual neuron in that group fires in response to subtle differences in the incoming stimulus. Typically neuroscientists average out this heterogeneity to obtain their results, assuming that the variability is a "bug of biology."
"When we think about computer chips, variability in hardware clearly can be very destructive. Manufacturers spend a lot of time and expense making sure each processor on a chip is identical," Urban said. "The brain is considered to be one of the most sophisticated computers there is. We were intrigued by the idea that the brain might make use of the messy, complex nature of its biological hardware to function more efficiently."
Urban and postdoctoral student Krishnan Padmanabha
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Carnegie Mellon University