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>We experience the world at one second per second There is evidence from animal studies that the hippocampus (a brain structure critical for memory) can 'repla

>We experience the world at one second per second There is evidence from animal studies that the hippocampus (a brain structure critical for memory) can 'replay' remembered events at 10-20x speedup. See, for example: http://www.ncbi.nlm.nih.gov/m/pubmed/19709631/ http://www.ncbi.nlm.nih.gov/m/pubmed/19709631/ Video at: http://youtu.be/Bv7zN2Or6Mg http://youtu.be/Bv7zN2Or6Mg (Full-disclosure: I am the first author.) And in fact the OP uses biologically-inspired off-line replay as part of their learning algorithm.

_abattoir 12y ago
Fascinating. Does this relate to the speed of dreams? i.e. a "dream" might seem to have taken hours when in fact the REM sequence was on the order of seconds?
- GenerocUsername 12y ago
  Almost certainly. In real time, the brain is processing all incoming stimulus. In a dream/imagined scenario, you are only processing as much as you your brain is pushing into the scenario. Your not collecting millions of photons via your eye and interpreting a ball as green, your brain just says "green ball" and moves on, allowing for much faster replays/dreams than real-world experience.
- chockablock 12y ago
  Could do--the phenomenon was first seen in sleeping animals. Replay during REM is probably at 1X speed, non-REM (aka slow wave sleep) is in the 10-20x range. The dreams you remember (long, emotionally involved) tend to happen in REM. Of course, we can't ask rats what they dreamt about, but the patterns in the neural activity are very specific (we can decode the rat's position with ~5cm accuracy, and during replay we see coherent trajectories through space that look just like real movement.) Also Hassabis knows this literature well--he has published work on decoding human memories in hippocampus from fMRI data and we talked shop about replay a long time ago. (Very thoughtful and friendly person FWIW).
kriro 12y ago
This is pretty interesting (the high level conclusion, I do not claim to understand more). I've recently done a bit of pretty light research on the sense of smell (in the context of AR/VR) and it seems like smell can "transport you across time/space" faster than other senses. Might be an interesting follow up. If one can speed up recent events for quick recall/learning naturally maybe smell can somehow be used to speed up the going back in time aspect (some smell trigger to make the event feel recent+the 10-20x speedup combined)?

_abattoir 12y ago

Fascinating. Does this relate to the speed of dreams? i.e. a "dream" might seem to have taken hours when in fact the REM sequence was on the order of seconds?

GenerocUsername 12y ago
Almost certainly. In real time, the brain is processing all incoming stimulus. In a dream/imagined scenario, you are only processing as much as you your brain is pushing into the scenario. Your not collecting millions of photons via your eye and interpreting a ball as green, your brain just says "green ball" and moves on, allowing for much faster replays/dreams than real-world experience.
chockablock 12y ago
Could do--the phenomenon was first seen in sleeping animals. Replay during REM is probably at 1X speed, non-REM (aka slow wave sleep) is in the 10-20x range. The dreams you remember (long, emotionally involved) tend to happen in REM. Of course, we can't ask rats what they dreamt about, but the patterns in the neural activity are very specific (we can decode the rat's position with ~5cm accuracy, and during replay we see coherent trajectories through space that look just like real movement.) Also Hassabis knows this literature well--he has published work on decoding human memories in hippocampus from fMRI data and we talked shop about replay a long time ago. (Very thoughtful and friendly person FWIW).

kriro 12y ago

This is pretty interesting (the high level conclusion, I do not claim to understand more). I've recently done a bit of pretty light research on the sense of smell (in the context of AR/VR) and it seems like smell can "transport you across time/space" faster than other senses. Might be an interesting follow up. If one can speed up recent events for quick recall/learning naturally maybe smell can somehow be used to speed up the going back in time aspect (some smell trigger to make the event feel recent+the 10-20x speedup combined)?