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For the first time, scientists have taken a live image of newly formed neurons in a brain, as reported by New Scientist. This breakthrough was achieved by a team of neuroscientists at Columbia University. Their study, featured in the journal Neuron, indicates that neurogenesis, or the creation of neurons, aids mice in distinguishing between similar experiences. This discovery holds potential for future therapies targeting anxiety, depression, and stress-related conditions.
It was previously believed that humans are born with a fixed number of neurons. However, researchers later discovered that specific brain regions, especially the hippocampus—a small area linked to learning and memory formation—continue generating these cells throughout life.
Despite this, observing the formation of new neurons in a living organism had never been accomplished. To explore how these neurons differ in function, Attila Losonczy and his team at Columbia University Medical Center genetically engineered mice to make new neurons visible under light. They then exposed the mice to various stimuli, ranging from harmless to fear-inducing, to study their responses.
After the mice developed mental connections to these experiences, researchers deactivated the newly formed neurons using optogenetics, a technique that allows cells to be controlled with light, as reported by Science magazine. This action caused the mice to lose the ability to distinguish between frightening stimuli, such as a chamber where they had received an electric shock, and a safe, shock-free chamber. “This indicates that new neurons play a crucial and unique role in memory processing, enabling animals to differentiate and separate memories,” Losonczy explained to New Scientist.
In a follow-up experiment, researchers captured an image of the new neurons. They implanted a device equipped with a mini-microscope into the mice’s brains, exposed them to similar yet distinct stimuli, and observed how the activity of new neurons differed from that of mature ones. The study revealed that new neurons were “more responsive” than older ones, potentially making them more effective at processing new information. Additionally, they might help regulate the activity levels of mature neurons. Since these cells encode similar but distinct memories, neurogenesis could play a key role in helping the brain differentiate between different situations.
Individuals with panic or anxiety disorders often struggle to differentiate between similar events (for instance, as New Scientist notes, distinguishing between a gunshot and a car backfiring). Experts suggest this difficulty may stem from insufficient neurogenesis. Given that depression and schizophrenia also appear to impact neuron formation, further research into the behavior of these new cells could provide insights into these complex mental health conditions.
