Saturday, September 10, 2011

Hippocampus builds memories of the future


Research suggests that hippocampal cells fire in a particular pattern as an animal explores a novel situation, and then that same firing pattern is replayed afterwards during rest or slow-wave sleep to consolidate the encoding of that experience.  This is how we learn and remember.

A study done at MIT by George Dragoi and Susumu Tonegawa, published in Nature in Jan 2011, suggests that hippocampal cells can also be observed starting to encode a novel experience before it happens.  In other words, the brain is remembering something from the future or learning something that has not happened yet.

This prescient hippocampal firing happened during a rest or sleep period before the novel activity.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104398/

6 comments:

  1. I've called this a 'prememory'
    Not sure if that term has been used ~if so~my apologies

    Beannamated

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  2. Thanks for commenting, Beannamated! There is, apparently, quite a bit of other evidence for backward time in the brain. I'll try to find it. Or if you find anything good, please send me the link.

    Would you be interested in giving an example of a "prememory" you've experienced?

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  3. This is very reminiscent of something called "presentiment" by Dean Radin. He has studied people exposed to pictures displayed on a computer while the physiological state of arousal was measured. The pictures are mostly unexciting, but one in every four (random timing) is an upsetting image. Again, people seem to anticipate the upsetting image by reacting ahead of time.

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    1. Yes, you're absolutely right -- it does seem to fit well with Radin's presentiment work. Thanks for bringing it up!

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  4. Very interesting study. As David said, this is reminiscent of presentiment and precognition more generally. But of course, the authors of the study implicity assume that causality always flows forward in time and this inevitably constrains both the design of the experiment and their interpretation of the results - that is, the "preplay" firing activity causes a similar pattern of firing during exploration of the novel arm (rather than the other way round as is being discussed here).

    It may be possible for this team to design another study that could rule out a forward-causal interpretation (have an extra condition where you measure "preplay" firing activity but the mice *don't* explore the novel arm?). However, I won't hold my breath that they would try it, and I doubt it has even crossed their minds. If we eventually discover that retro-causation in the nervous system is a routine occurrence, this experiment may be a nice example of how we used to overlook it because we started with the wrong assumptions. However, I think we should also bear in mind that the results of this study may simply be due to causation flowing forward in the normal manner. But I've never been one for parsimony...

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    1. We really are transitioning from one understanding of reality to another, aren't we? Like the Copernican Revolution. As you say, people will look back on the 20th c. and fondly shake their heads over how "those people" could have believed that there was no such thing as retrocausation, precognition, clairvoyance, etc., when, in fact, "now everyone knows" they're going on all the time. Thank you for your comment!

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