Cortical reactivations predict future sensory responses. (https://www.nature.com/articles/s41586-023-06810-1)

These scientists wanted to understand how our brain remembers things we see. They knew that when we see something important, like a bright light or a loud noise, certain groups of brain cells called neurons become active. They wanted to see if these active neurons would stay the same or change over time.

To do this, they used special equipment to look at the brain of mice while they were shown different images. They focused on a part of the brain called the lateral visual cortex, which helps us see and process what we see. They used a special dye that can show when neurons become active by measuring the levels of calcium in the cells.

They found that after the mice saw an image, the active neurons in their brains would reactivate for a short time. This reactivation was like a replay of the image in their brains. They also noticed that these reactivations happened together with another brain activity called sharp-wave ripples.

To test if these reactivations were important for memory, the scientists stopped the neurons from becoming active during the image presentation. They did this by using a special technique to temporarily "silence" the neurons in the brain. When they did this, the reactivations didn't happen anymore.

The scientists also noticed something interesting. The reactivations that happened early in the experiment were different from the ones that happened later. The early reactivations were more similar to the future reactivations, while the later ones were more similar to the past reactivations. This means that the way the neurons reactivate can predict how the brain will remember things in the future.

In fact, the scientists were able to use the rate and content of these reactivations to predict how the brain's responses to different images would change over time. This means that the reactivations play a role in how our brain remembers things and helps us tell different things apart.

So, in summary, these scientists studied how our brain remembers what we see. They found that after we see something, certain groups of brain cells become active again for a short time. These reactivations help our brain remember things and tell them apart.

Nguyen ND., Lutas A., Amsalem O., Fernando J., Ahn AY., Hakim R., Vergara J., McMahon J., Dimidschstein J., Sabatini BL., Andermann ML. Cortical reactivations predict future sensory responses. Nature. 2024 Jan;625(7993):110-118. doi: 10.1038/s41586-023-06810-1. Epub 2023 Dec 13.