OMG – you were in my dream last night! This may be good or bad, surprising or disturbing, but most of us have had dreams with bizarre circumstances or the appearance of unusual characters, like your boss or your mother-in-law. But for many of us there is little recollection of anything else. Sometimes we can remember a few details of our dreams when we first wake-up. This especially happens when the thing that wakes us up (like the ringing phone) is actually part of what’s going on in our dream. But even that information tends to fade as the day goes on. Recently, a friend at work was vividly recalling a dream that she’d had the night before, and I must admit that I had a hard time believing that she could actually remember so much. I investigated this a bit further and, as it turns out, many people can recall their dreams quite vividly. So, why can’t I?
In the middle of last year Neuroscientists figured out that people who can frequently recall their dreams wake up at night nearly twice as often as people who rarely recall their dreams. One reason why these high dream recallers wake up more often, at least partly, is because they also are more sensitive to sounds, and thus more likely to be awakened by them . This makes sense, since once awake there is the opportunity to consciously remember the dream. This made me wonder: on the rare occasions when I do remember my dreams, is it because I had a poor night’s sleep? Or might there be something fundamentally different between my brain and the brains of people who remember their dreams regularly?
There was another interesting finding in this study showing differences between high and low dream recallers, but it is complicated and difficult to see how it relates directly to dreams. But here goes… As it turns out, people who recall their dreams (the same ones who awaken more easily to sounds in general) also respond more strongly to the sound of their own name when they are awake. In this study, participants were divided into high dream recallers and low dream recallers, and they were played music which had someone speaking their name in the middle of the music. The brains of the high dream recallers showed very high responses to the sound of their name, compared to the brains of people who don’t remember their dreams. The researchers argue that this is an indication that there are fundamental differences in the way that the brain responds to sounds in the two groups of people. OK. I can buy that, but they didn’t actually link this to dreams and sleeping. In fact, when the same scenario was repeated but to people who were asleep, there was no difference in the responses of anyone’s brain to the sound of their name. At this point we’re left with a curious observation that high and low dream recallers have differences in brain activity and responsiveness when they are awake. But what’s that got to do with dreaming?
More recently, researchers have tried to answer this question by using brain scanning technology called positron emission tomography (PET), which essentially allows scientists to monitor activity in the brain, in real-time, in people who are awake or asleep . The researchers found that two regions of the brain, the temporo-parietal junction and the medial prefrontal cortex, were more active in high dream recallers, awake or asleep, than in people like me. I found this much more interesting, because these brain differences better explain the differences in dreaming and sleeping between the two groups. This also supports the previous study, suggesting that low dream recallers like me really may be different from high dream recallers in some of our awake behaviours too. Just what these behavioural differences might be are still unclear. An even more interesting question is: what about people who used to remember their dreams, but now they don’t or vice versa. This research suggests that their brains have changed, and that the brain changes could affect their awake behaviours too.
To me, that’s really interesting to think about. We know that our environment can lead to changes in our behaviours because of changes in our brain structure and function. This is the basis of learning and memory. Actual structural changes in our brain happen when we remember things that we’ve learned, such as multiplication tables, the route to work, or not to touch the hot stove. And in experiments where the brain changes were blocked from happening, individuals were no longer able to retain memories of what they learned. What we don’t know is whether the brain function that gives rise to the awake behaviour influences the dream remembering, or whether the dream remembering brain function brings about certain awake behaviours. It’s a bit of a chicken-and-egg problem. So if we think about who used to remember their dreams, but don’t any more, here’s the question: might they have had some experience that caused their awake behaviours to change (new work environment, changes in life or lifestyle), and that the brain changes that happened to support this awake behaviour change this also resulted in changes to their brains’ ability to remember dreams? It’s a tough problem to get your head around and think about, but fascinating to consider the possibilities.
But there is a completely other way of looking at how brain activity relates to dream recall. What if people who recall their dreams actually dream more, so that they just have a greater chance of remembering something? If this were the case then the differences in brain activity might relate to differences in the ability to form dreams rather than to recall them. This could have an influence on awake behavoiur in some unknown way; perhaps people with lots of dreams have more active brains when awake as well, and are thus more sensitive to their name and other sounds. This must await further research. I hope you can see that even in just this one small aspect of what our brains can do there is enormous room for further research and understanding; understanding that will enlighten us as individuals into what makes us “tick”, but also in the realm of assisting people with mental illnesses in which their brains respond unusually to their environment. In the meantime I am content to be a low dream recaller because I am able to enjoy a good night’s sleep undisturbed by creepy images of my mother-in-law carrying automatic weapons whilst in the loving arms of Rasputin. Do enjoy your evening ahead.