Neuron Competitions Improve Memory

One of the ways the human brain uses to improve its memory capabilities is to stage competitions between individual nerve cells called neurons. These stand-offs improve the neural circuitry that memories relies on, allowing people to remember things more vividly.

Scientists at the University of Michigan, who conducted the study, say that these discoveries could be used to develop new ways of treating disorders such as Alzheimer’s disease, autism and schizophrenia.

The research team published the full details of its investigation in the latest issue of the esteemed medical journal Neuron. The paper highlights the workings of a set of neural circuits involved in multiple neurological disorders.

In order to understand the circuitry, it is first important to know that neurons have filaments called axons that can extend very far out from the cell's body. Some axons have been measured to exceed 10 centimeters in length.

They are used to connect one neuron to others. The more axons a neuron has, the more connections it can create. Studies have demonstrated that a single nerve cell can link up to as many as 10,000 others.

As they are used, these circuits become more efficient at the job they do. If they do not adapt, then the brain sends orders to dissolve them, and creates new ones. When the networks are insufficiently refined, they trigger neurological disorders.

“Much of our understanding of the brain’s wiring has come from studying our sensory and motor systems, but far less is understood about the mechanisms that organize neural circuits involved in higher brain functions, like learning and memory,” explains Hisashi Umemori, MD, PhD.

“We wanted to know how brain circuits become more efficient during the brain’s development. Does the brain choose to keep good connections and get rid of bad ones and, if so, how?” adds the expert, who is the senior author of the new paper.

In a series of experiments, the researchers genetically engineered mice that could have some of their neurons switched off externally. For the study, experts selected neural pathways connecting the hippocampus, a center for learning an memory, to an area coding for perception and awareness.

In some mice, the team shut down up to 40 percent of these neural connections. Within days, the brain dissolved the inactive links, leaving only those that were still active to continue operations.

One of the reasons why this happens could be that the brain is an extremely energy-hungry organ. That is to say, it consumes a lot of the body's reserves, and it cannot waste any energy on non-functioning neurons, PsychCentral reports.

“This tells us that the brain has a way of telling among a group of neurons which connections are better than others. The neurons are in competition with each other. So when they’re all equally bad, none can be eliminated,” Umemori comments.

“The better we understand how these mechanisms work, the better we’ll be able to understand what’s happening when they aren’t working,” the expert concludes.