A new study by researchers at the NYU Langone Medicine Center has revealed that the ability to learn new information and retain lifelong memories seems to lie in the minute junctions where nerve cells communicate.
Study's lead author Wen-Biao Gan, associate professor of physiology and neuroscience at NYU School of Medicine, and colleagues found that a delicate balancing act occurs in the brain where neuronal connections are continually being formed, eliminated, and maintained.
The new study suggests that this feat allows the brain to integrate new information with no threat to already established memories.
Using a powerful optical imaging technique called two-photon microscopy, the researchers viewed the precise changes that take place at synapses, the junctions where nerve cells communicate, in the wake of learning a new task or being exposed to a novel situation.
Gan said that new knowledge prompts alterations in the dendritic spines, the knobby protrusions along the branching ends of nerve cells. With learning, spines are gained and others lost.
"We've known for a long time that the brain remodels after learning. Our studies show that the brain does this in two ways: by adding a tiny fraction of new connections to the brain's neural circuitry and eliminating old ones," Gan said.
The study gives a clue as to how it is possible for humans, who have hundreds of thousands of spines on one neuron, to live each day, constantly experiencing and learning new things, without losing existing memories.
"The brain is a dynamic and stable organ," Gan said.
The study is published online this week in the journal Nature.