Deja Vu in Lucid Dreams

Deja vu is a French phrase given to the peculiar sensation that we have done something before.  I've had lucid dreams where I exerience deja vu -- only I've dreamt this dream before.  I've been searching and searching for other experiences of lucid dreamers feeling that they have dreamt this dream before but have not been able to find anything.  If anyone knows of any research, experiences or book quotes, I'd love to see them.

There hasn't been much proof that deja vu in waking life means much of anything other than a possible malfunction of memory, but what about feelings of deja vu when dreaming?  This 2008 study indicated that stimulating the hypothalamus can trigger feelings of deja vu. Perhaps in some instances the hypothalamus is stiumluated during a lucid dream? I'd love to know.

People who complain about chronic deja vu often have neurological problems such as temporal lobe epilepsy or a dissociative disorder.  I don't have that, but I do have major depression and post traumatic stress disorder.

You have to be lucid in order to realize that you are dreaming.  You can slip in and out of lucidity in the course of an individal dream, but there has to be that initial realization -- "Oh, this is a dream!" before you can recognize that you have dreamt this dream before.

Of course, I could also be dreaming that I think I've dreamt this dream before, but it's happened to me so often (many times a year for the last 30 years or so) that I think it has less to do with the individual dream and more to do with how the brain uses dreams to help with memories.

The function of dreams may have more to do with memory processing and consolidation more than anything else.  A study reported on by National Geographic suggests that dreams also try to ease painful memories.  Somewhere along the line, memories of waking life and memories of dream life are bound to get mixed up. 

Image of Rodin's The Thinker by Andrew Horne for Wikimedia Commons.