We’ve all heard about that oft-used trope that we humans have been only using a fraction of our available brain power—that up to ninety percent of our gray matter is unused. This has led to much speculation as to how this can manifest—from potential increases in intelligence to outright telepathy—and to find ways of unlocking this supposed dormant percentage.
In the past, neurologists and neuroscientists have debunked this as an urban myth (see here). The ‘ten-percent myth’ (among other persistent assertions) was invalidated by our increasing understanding of how our brain cells are structured, and how they work. But what if there was indeed a possibility that the brain can be more active than we thought? And that we may indeed tap into this unused potential, by looking somewhere else?
We have long established that action potentials or nerve impulses originate from the body of the neuron or nerve cell; these impulses are then transmitted to the next neuron, which would subsequently fire and so on. Scientists at the University of California Los Angeles instead began looking at the structures branching out of the nerve cell called dendrites. Dendrites were simply seen as the passive conduits that bridged these transmissions. But when researchers monitored dendritic activity in laboratory rats as they were made to run through mazes they noted that apart from the transmissions generated by the neurons, there was also increased activity within the dendrites themselves.
What the scientists found out was that dendrites, in fact, generate their own impulses, and at rates up to 10 times more than those emanating from the neuronal bodies; this means that dendrites actively contribute to the transmission process. Furthermore, variations in the voltages of these dendritic signals were also seen. The nerve cell is commonly compared to a digital computer, where the firing of nerve impulses is binary (all-or-nothing) in nature. If dendrites indeed generate impulses at different voltages, this means that our nervous system may be more analog in nature, where to serve a specific purpose different signals may be firing off at different areas.
Furthermore, because dendrites are nearly 100 times larger than the neuronal bodies, in terms of volume, the brain may theoretically have an equivalently larger area for computational space. This, the scientists say, may prompt us to look at the nervous system in a different light, as well as find ways to harness this available space for learning and memory, and perhaps in rehabilitation from trauma or disease.