Real Brain Power: Tiny Neural Computer Created with a Single Dendrite

The human brain may have more potential than scientists once believed. It turns out that the orientation computations that our brains perform on a daily basis can be carried out by the microscopic branches of neurons known as dendrites, which are the receiving elements of neurons. This, in turn, reveals that these dendrites have a lot more power than scientists once believed.

When you look at the hands of a clock or streets on a map, your brain effortlessly performs computations that tell you about the orientation of these objects. In order to learn a bit more about the human brain, though, the researchers examined neurons in areas of the mouse brain that are responsible for processing visual input from the eyes. More specifically, the researchers managed to make incredibly challenging electrical and optical recordings directly from the tiny dendrites of neurons in the intact brain while the brain was processing visual information.

So what did the scientists see exactly? They witnessed specific electrical signals in the dendrites, triggered by visual stimulation. These bursts of spikes were tuned to the properties of the visual stimulus.

"This work shows that dendrites, long thought to simply 'funnel' incoming signals towards the soma, instead play a key role in sorted and interpreting the enormous barrage of inputs received by the neuron," said Michael Huasser, one of the researchers, in a news release. "Dendrites thus act as miniature computing devices for detecting and amplifying special types of input."

In fact, the results challenge the widely held view that this kind of computation is achieved only by a large number of neurons working together. Instead, it seems that the basic components of the brain are exceptionally powerful in their own right.

"This new property of dendrites adds an important new element to the 'toolkit' for computation in the brain," said Hausser in a news release. "This kind of dendritic processing is likely to be widespread across many brain areas and indeed many different animal species, including humans."

The findings are published in the journal Nature.