A good study, We need to learn as much as we can about the brain!

A great way to promote theta waves and relaxation is through floatation therapy. It would be interesting to see the effects of frequent floating on memory, I suspect it would be profound. It is the most relaxing experience I have ever had, by far!

This I completely believe. I know from my own experience that when I am stressed, overwhelmed and horribly busy, my memory does not work very well and I am not at the top of my powers. But when I relax, and give myself the luxury of time and thought, my memory is excellent, and my brain in full gear.

http://graciouslivingdaybyday.com/

This is what meditators have known for a long time. With a relaxed state of mind we focus better as our attention is in the here and now. Research shows that regular meditation changes the physical structure of the brain (thickening of the cerebral cortex), which helps increase attention span, sharpens the ability to focus and improves memory. But even if we don't meditate, a relaxed state of mind certainly improves our focus and memory. When we are not relaxed we usually think (worry, ruminate, etc) too much. Negative and futile thinking makes us feel stressed and stress affects our cognitive skills and our memory.

Dr Christine Maingard, Author of "Think Less, Be More" - http://www.thinklessbemore.com