Conservation (being conservative) & memory

Austria is known as a conservative country, and I think I've mentioned before that it makes me understand why people are conservative sometimes. It is a pleasure to be somewhere that still takes the seasons seriously in their cuisine, for example.

Today many people are in costumes in town. Not like the kind of crappy store-bought or thrown-together-by-kids costumes we used to wear for Halloween. People have made them very nicely out of nice material and such. It is Fastnacht (Faschingsdienstag in Austria). The links mostly talk about how this is connected to Lent, but in fact it goes back further than Christianity in this area. My PhD student Hagen says that the twelve nights of Christmas were originally the 12-day hunt of Odin, held after the solstice, and then tied the carnival into them (from "carne", because they finish the stores of food for winter & then fast until spring, essentially.) He said the carnival was to frighten away the evil spirits that were woken up by the hunt (or something.) The wikipedia page does mention something about evil spirits.

When I was in Prague for the primate conference I spent an afternoon at their museum and was blown away by the one room with archaeological results. This part of Europe has incredibly ancient culture; apparently the hills around here were critical to civilization's development in Europe -- maybe even for the Neanderthals as well as our species. It's really incredible to be in touch with a new set of threads from those times. Especially while I'm here studying the evolution of culture.

Yesterday we had a speaker at the KLI talking about how the brain controls and regulates sleep, and speculating on what this tells us about memory and consciousness. Essentially, the executive and external sensing functions get shut off, so you are experiencing what it is like to have half your brain on when you dream. From what I already knew (from machine learning & neuroscience) I know that people think we use dreaming to consolidate long-term memory from the traces left of episodic & working memory from the day. Essentially the brain updates its long-term expectations based on its recent experiences. But this researcher, Allan Hobson, made a big deal about the fact that one part of the forebrain (near the executive) that is left on (in fact, stimulated) is the amygdala / emotion system.

I have read before that most memory consolidation actually seems to occur in NREM (non-REM) sleep, and REM only occurs in mammals. Hobson said that REM is "super sleep" which all animals would use all the time except its so dangerous -- you shut off your thermal regulation and any awareness of the outside. If this were true you would expect social animals to have it whether they were mammals or not. But I also know that REM is implicated with dealing with distressing events, both for humans and rats. So, for example, humans that have watched distressing movies (e.g. about war or car accidents) and then allowed to have REM sleep are less distressed by the same movie the next day, but people who are allowed to sleep almost as normal but stopped from REM sleep are just as distressed the second day.

I'm just finishing up a grant on understanding (& replicating) the role of emotions in action selection, and during that work I got convinced that emotions correlate highly with evolved homeostatic goals. But of course we know for people at least we can change our goals over our lifetimes. I wonder if REM sleep is like NREM sleep, but instead of updating our expectations, its for updating our goals? Hobson has a lot of data showing that dreams often seem to be about resolving weird dilemmas, so you feel like you are trying to find a single solution to two conflicting sets of information all the time. It could be that it just because there is so much bizarre content in dreams and when you (occasionally) become aware while dreaming you get perplexed & try to resolve it. But maybe it feels that way because your brain really is looking for a better goal configuration. That would also explain why you have more dreams/REM sleep while you are stressed.