For the first time, scientists at the University of Michigan Health System have discovered that two distinct types of competition between brain cells stir up the memory circuit development.
Explaining how the brain shapes up, the scientists said that the brain cells grow and extend along pathways to link different parts of the brain.
As the brain develops, these connections fine-tune themselves and become more efficient. Any problems with this refinement process may be responsible for some 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," said Hisashi Umemori, assistant research professor at U-M's Molecular and Behavioral Neuroscience Institute.
The scientists focused on an important connection between the hippocampus, which is crucial for learning and memory, and the cerebral cortex, which is key for perception and awareness.
They deactivated about 40 pc of the neurons in the connection and over a matter of days, watched as the brain eliminated the inactive neural connections and kept only the active ones.
The experiment also showed that if all the neurons were deactivated, their connections were not eliminated.
"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 added.
The study has been published in the journal Neuron.