Here at Top Comments we strive to nourish community by rounding up some of the site's best, funniest, most mojo'd & most informative commentary, and we depend on your help!! If you see a comment by another Kossack that deserves wider recognition, please send it either to topcomments at gmail or to the Top Comments group mailbox by 9:30pm Eastern. Please please please include a few words about why you sent it in as well as your user name (even if you think we know it already :-)), so we can credit you with the find!
Source
Electrical brain activity differs markedly while we’re awake and while we’re asleep. While we (and other mammals) are awake, the brain’s electrical activity chugs along at steady pace, for the most part, particularly while we’re in the process of doing something. However, during sleep, there are sudden bursts of activity called “sharp wave ripples” that puzzled brain scientists since they were discovered in the late 1960s. Within a decade, it was determined that these ripples were associated with memory formation. Experiments performed in the 1990s and 2000s, when new technology first made it possible to monitor hundreds of individual neurons, showed that the sharp wave ripples that occurred during sleep were replays of of the animals’ daytime brain activity, but with frequencies 10 to 20 times higher. The role of these ripples appears to be in the transfer of a waking memory to long-term storage.
Imagine an experience as “a melody on the piano,” said Daniel Bendor, a neuroscientist at University College London. A specific sequence of neurons fires to record an experience, just as a pianist taps out a specific sequence of keys. Then, during sleep, the hippocampus replays that sequence — but faster and potentially hundreds or thousands of times. The frenetic sharp wave ripples propagate out from the hippocampus, a way station in the brain for “episodic memories” of particular experiences, toward the cortex, which is involved in long-term memory storage.
However, an additional discovery was made that these sharp wave ripples also occur while the animal is awake, but resting rather than active. What is the purpose of these ripples during waking hours? Apparently, this is how the brain “tags” a memory for long-term storage. Memories that don’t receive a tag are discarded.
Researchers monitored mouse brain activity by running them through a maze while recording the neuron firing sequences while the mice were running the maze. They then observed sharp wave ripples of the same sequence while the mouse rested, and then again while it was asleep. Interestingly, when the same mouse runs the same maze on a different day, the neuron firing pattern is different. Presumably, this allows the animal to distinguish the memories of running the maze on different days. (What did you do at work yesterday, versus what did you do at work the day before.)
What is not yet known is how particular memories are triaged for tagging. How does the brain decide what’s important enough to go into long-term storage? From our own experiences, we know that this is going to be highly dependent on the individual organism, as any group of individuals experiencing the same event will emphasize different aspects of it. Like most other aspects of living organisms, memory evolved to improve the odds that the organism would survive long enough to reproduce, so the selection process for long-term storage is pretty important. It will be interesting to see if this mechanism can be determined.
Comments are below the fold.
Top Comments (May 23, 2024):
From inkstainedwretch:
rebel ga comments in Walter Einenkel front page diary on Gov. Ron DeSantis banning rainbows.
Voting for people who hate and hurt the people supposedly loved by voters is a not inconsiderable fraction of the MAGA base. Many of them either foolishly or willfully don't see that their candidates are godawful people.
Top Mojo (May 22, 2024):
Top Mojo is courtesy of mik! Click here for more on how Top Mojo works.
Experiencing technical difficulties. Check back in a day or two.
Top Photos (May 22, 2024):
Thanks to jotter (RIP) for creating it and elfling for restoring it!