The brain has often been referred to as a computer for its ability to oversee, process, and carry out numerous functions at once. Now, a recent study by scientists at the University of North Carolina Chapel Hill and University College London reveals just how literally true that comparison is. In fact, it seems that the brain is really a supercomputer, as it has tiny computers within it.
The paper, which was published in Nature, focuses on dendrites, which are tiny (one hundred dendrites would comprise the width of a strand of human hair), tree-shaped extensions on neurons that receive information, namely in the form of electrical stimuli, and transfer it to the body of the cell. Scientists have long known that dendrites transfer information, but it turns out they do a whole lot more than that — they actually process information too.
Scientists also knew that dendrites can create electrical spikes, but they didn’t know whether that was just due to run-of-the-mill brain activity or whether that was associated with some other function. For the recently published study, researchers essentially listened to the dendrite signaling process in mice.
Since Bose doesn’t make equipment suitable to the task, they had to use something called a patch pipette, which is a fine-tipped glass electrode small enough to get inside a cell. Then, leveraging earlier research proving that mice (and humans) have neurons that respond to vertical image orientation and others than respond to diagonal or non-vertical orientations, they showed the mice a bunch of black-and-white zebra-like stripes and recorded the electrical activity in the dendrites.
As the mice watched the striped images on the screen, scientists noticed that the dendrites’ signals formed unusual patterns. As they continued to observe, the researchers found that the spikes in the patterns occurred in direct response to the visual stimulus, and that dendrites fired even when others neurons didn’t. This means two things — that the dendrites were actually processing the visual information, and that the processing was specific to the dendrites. In a nutshell, the dendrites are processing or computing the visual information, which scientists believe is part of a bigger and more fundamental process in the visual cortex. Thus, it seems that dendrites are indeed “mini-computers.”
This experiment is the first in which anyone has recorded in a functioning brain an optimal impulse passing through a dendrite. The discovery lends important insight into how dendrites and cells process visual information and could eventually lead to advancements in neurology and ophthalmology.