What's the secret to remembering dreams?

How often, and how well, do you remember your dreams? Some people seem to be super-dreamers, able to recall effortlessly their dreams in vivid detail almost every day. Others struggle to remember even a vague fragment or two.

A new study has discovered that heightened blood flow activity within certain regions of the brain could help explain the great dreamer divide. In general, dream recall is thought to require some amount of wakefulness during the night for the vision to be encoded in longer-term memory. But it is not known what causes some people to wake up more than others.

A team of French researchers looked at brain activation maps of sleeping subjects and homed in on areas that could be responsible for nighttime wakefulness.

When comparing two groups of dreamers on the opposite ends of the recall spectrum, the maps revealed that the temporoparietal junction - an area responsible for collecting and processing information from the external world - was more highly activated in high-recallers. The researchers speculate that this allows these people to sense environmental noises in the night and wake up momentarily - and, in the process, store dream memories for later recall.

Advertisement

In support of this hypothesis, previous medical cases have found that when these portions of the brain are damaged by stroke, patients lose the ability to remember their dreams, even though they can still achieve the REM (rapid eye movement) stage of sleep in which dreaming usually occurs.

The sleeping brain cannot store new information into long-term memory - for instance, if presented with new vocabulary words to learn while asleep, you will wake up completely unaware of what you heard. But this leaves open the question of how one is able to recall vivid nightly visions in the morning.

"If the sleeping brain is not able to memorise something, perhaps the brain has to awaken to encode dreams in memory," said study author and neuroscientist Perrine Ruby of Inserm, a French biomedical and public health research institution. If awakened during a dream, the brain has the chance to transfer its faint flashes - via reiteration of the memory in one's mind - into more long-term storage. This hypothesis has been dubbed the "arousal-retrieval model".

"There's a real question about the difference between dreaming, encoding memories of those dreams and being able to recall them," said Harvard Medical School's Robert Stickgold, a sleep researcher who was not involved in the study. "For someone to remember their dreams, all three of those things have to happen."

Dreams exist first in working memory, or the memory we use to hold and manipulate thought fragments. Stickgold gives the example of hearing a five-digit number and then reciting it backward. But, like a fleeting dream, the series of numbers will erase in a flash if not put away into longer-term memory.

Visit link:
What's the secret to remembering dreams?