Introducing the brain: epigenetics in forming memories (Introduction)

by David Turell , Friday, July 26, 2024, 20:06 (118 days ago) @ David Turell

A mouse study:

https://www.sciencedaily.com/releases/2024/07/240725154641.htm

"When we form a new memory, the brain undergoes physical and functional changes known collectively as a "memory trace." A memory trace represents the specific patterns of activity and structural modifications of neurons that occur when a memory is formed and later recalled.

"But how does the brain "decide" which neurons will be involved in a memory trace?

"Studies have suggested that the inherent excitability of neurons plays a role, but the currently accepted view of learning has neglected to look inside the command center of the neuron itself, its nucleus.

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"Epigenetics is the mechanism of how cells control such gene activity without changing the DNA sequence.

"Now, scientists at EPFL led by neuroscientist Johannes Gräff have explored whether epigenetics might affect the likelihood of neurons to be selected for memory formation.

"Their research on mice, now published in Science, shows that the epigenetic state of a neuron is key to its role in memory encoding.

***

"A neuron can be epigenetically open when the DNA inside its nucleus is unraveled or relaxed; and closed when the DNA is compact and tight.

"They found that it is the open ones that are more likely to be recruited into the "memory trace," the sparse set of neurons in the brain that shows electrical activity when learning something new.

"Indeed, the neurons that were in a more open chromatin state were also the ones demonstrating higher electrical activity.

"The EPFL scientists then used a virus to deliver epigenetic enzymes to artificially induce openness of the neurons.

"They found that the corresponding mice learnt much better. When the scientists used the opposite approach to close the neurons' DNA, the mice's ability to learn was cancelled.

"The findings open up new ways to understand learning that encompass the neuron's nucleus, and may even lead one day to medication for improving learning. As Gräff explains: "They move away from the dominant neuroscientific view on learning and memory that focuses on the importance of synaptic plasticity, and newly place emphasis on what happens inside the nucleus of a neuron, on its DNA."

Comment: well, we see a mechanism to set a memory in place in DNA. That still doesn't tell us how recall actually works. I have a stored image, at two years + four months old, at a resort in the summer with my mother. The bull got into the tennis courts. I am standing on a bed at the window watching him. Same summer, same resort, my mother was stung by a bee, and had a bandage on her arm. For young me, a very exiting set of events fixed those memories.