Your short-term memories are replaying in your head in your sleep, on the way to becoming fixed in place. Your long-term memories are also replaying, keeping them in place. The processes for the two types of memories might interfere with each other, and there is a safeguard built in. Meanwhile, brain-mimicking artificial intelligence in the form of neural networks can show ‘catastrophic forgetting’ if great care is not taken when it’s trying to add new ‘memories,’ new capabilities.
Back to you and me, and, in fact, most vertebrate animals. Around 300 million years ago, animal brains evolved the part called the hippocampus – a little ‘seahorse’ that enables us to navigate, remember, and do some other things. It’s the gatekeeper for those memory replays. Recently, Hongyu Chang and 6 colleagues at Cornell University investigated how the hippocampus interleaves the replays of short-term and long-term memory without interference. They found that sleep in mice has regular bouts of shutting recent memories on and off. Why mice for this study, in particular? Well, mice sleep wit their eyes open, so the changes in pupil size that track the bouts are easily seen. The researchers used really advanced technology to turn things on and off in areas of the brain using light pulses. There’s a bionic mouse!
This is an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org
Source: Nature, 30 Jan. 2025, pp. 1161 ff.
Image: My creation in PowerPoint
