It didn’t come as a surprise to me when I learned from neuroscience postdoctoral scholar Tatiana Engel, PhD, that all of us have a bit of noise in how our neurons fire. In response to the same signal, they’ll usually fire one way then occasionally fire a different way.
I, myself, blame a number of my quirks on noisy and confused neurons.
Engel told me that Stanford Neurosciences Institute director William Newsome, PhD, had discovered those noisy neurons almost two decades ago. He had trained animals to detect whether dots on a screen were moving to the right or left. He found that the way a single noisy neuron fired was also reflected in how the animal categorized the dots – if the neuron indicated right, the animal chose right and vice versa.
In a story I wrote Engel said, “[It]was exciting to me to realize that we are used to thinking about ourselves as agents who are in charge of our decisions and in charge of our thoughts, but the brain might be playing tricks with us.”
Engel recently published work she did in computer models in which she tried to understand why the neurons didn’t fire the same way every time. What she found is that if neurons don’t have a bit of a bias to begin with they don’t learn through a reward system. Essentially without occasionally firing left when the dots are moving right, the neuron can’t ever improve its accuracy.
The type of learning Engel studied is the same kind of learning we use when learning to categorize food into groups we like or don’t like, or to categorize music or even objects. Her work appears in Nature Communications.
Previously: Stanford neurobiologist Bill Newsome: Seeking gains for the brain and Deciphering “three pounds of goo” with Stanford neurobiologist Bill Newsome
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