Researchers are beginning to learn the mechanisms behind the brain’s storage of short-term and long-term memories. Scientists have long known that the two systems work together but researchers from the University of Tübingen discovered that some processes happen much faster than previously believed. The findings are in a paper that was just published in the journal Proceedings of the National Academy of Sciences.
The human brain needs to be able to record certain memories for permanent use and it accomplishes this feat with the hippocampus, which stores long-term memories. The formation of long-term memories is considered to be a slow process, however, and possibly too slow for all of the information our brains constantly take in. In order to compensate for this, the brain stores short-term memories in the neocortex, a part of the brain located in the cerebral cortex. This means that the brain must often move short-term memories to the hippocampus for storage but the details of this process were unknown.
A research team conducted an experiment in which they had participants solve computer mazes while undergoing magnetic resonance imaging (MRI) scans. In one experiment, the maze stayed the same while in another, the maze constantly changed, preventing individuals from memorizing the layout. This allowed the researchers to better study how spatial memories were formed.
The team found that long-term memories begin forming right away, challenging previous beliefs. The connections between the hippocampus and neocortex are strongest at the beginning of memory formation and the connections weaken as the memories form. Repetition sped up the process and allowed long-term memories to form very quickly, in less than a day. This was unexpected because scientists had previously thought that this process would take weeks or even months.
The team’s findings further our understanding of how memories are stored in the human brain. This may help scientists develop treatments for certain memory disorders. The study also emphasizes the importance of repetition when learning and may provide new insights into education techniques.
Brodt et al. Rapid and independent memory formation in the parietal cortex. Proceedings of the National Academy of Sciences (2016).