Seed. Feb 07. Yohannes Edemariam

Every moment of our lives is haunted by uncertainty; we are surrounded
by indefinite clues as to how to proceed into the future. Yet
experiments on human behavior have shown that our brains are
remarkably adept at arbitration. Over the last decade or so,
psychologists have found that, when it comes to assimilating sensory
information and using it to make simple, everyday decisions, humans
operate at a near optimal level. We seem to be wired to carry out
Bayesian inference, a highly efficient statistical calculation.
How is such a feat carried out by our neurons, the cells responsible
for our every thought? The question is difficult because neurons, when
exposed to the same stimulus repeatedly (for example, when a viewer is
shown the color red over and over), seem to fire a different number of
signals to other neurons each time. The variety in signals is known as
"noise." Traditionally, neuroscientists have grouped the "noisy"
signals into statistical groups called Poisson distributions, and
considered them a hindrance to decision making, a messy byproduct of
evolution that the brain needs to edit for correct information with
which to form conclusions.  How this editing occurs has remained
largely a mystery.
But a group of scientists, among them Wei Ji Ma and Alex Pouget of the
University of Rochester, recently published a theory in Nature
Neuroscience that may, eventually, clear up the confusion: noting that
Poisson distributions simplify the math when plugged into the
calculations of Bayesian inference, the paper suggests that "neuronal
noise" may not be a nuisance at all, but instead the brain's way of
providing as comprehensive a statistical representation of the
observable world as possiblethe brain's way of providing itself as
many options as it can.
Because the proposition remains entirely theoretical, the team is in
the process of designing experiments they hope will prove their
hypothesisthat each neuron sends out constantly differing signals not
because it is inefficient, but because it is doing its best to mirror
the chaos in which we live.

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