Brain complexity: memory in hippocampus (Introduction)

by David Turell , Friday, July 08, 2016, 20:06 (3060 days ago) @ David Turell

Mouse studies have found a memory spot in the hippocampus:-https://www.newscientist.com/article/2096424-memories-of-favourite-locations-have-a-special-place-in-brain/-"Place cells are neurons that help us map our surroundings, and both mice and humans have such cells in the hippocampus - a brain region vital for learning, memory and navigation.-"Nathan Danielson at Columbia University in New York and his colleagues focused on a part of the hippocampus that feeds signals to the rest of the brain, called CA1. They found that in mice, the CA1 layer where general environment maps are learned and stored is different to the one for locations that have an important meaning.-"They discovered this by recording brain activity in the two distinct layers of CA1, using mice placed on a treadmill. The treadmill rotated between six distinctive surface materials - including silky ribbons, green pom-pom fabric and silver glitter masking tape. At all times, the mice were able to lick a sensor to try to trigger the release of drinking water.-"During the first phase of the experiment, however, the sensor only worked at random times. The mice formed generalised maps of their experience on the multi-surfaced treadmill, and the team found that these were stored in the superficial layer of CA1. -"Then the team activated the sensor only when the mice were on a specific surface, such as the one with silky strips. Mice learned to coordinate their licking with being on the “active” zone, and developed a map that was stored in the deeper layer of CA1.-"The team's conclusion, Danielson says, is that the superficial CA1 layer forms a stable baseline representation of the environment, while the deeper layer maps emotional significance.-“'It's like navigating to your favourite restaurant,” says Danielson. “You need to know the general area, and the wider environment, but the location of the restaurant is of special significance, and incorporates an emotional element,” he says."-Comment: Memories of favored events, i.e., one's wedding are thought to spread across much more of the brain. This study is much for more specific minor issues.