By Jessica Hamzelou / Source: New Scientist
"Am I awake or am I dreaming?"
I ask myself for probably the hundredth time. I am fully awake, just like all the other times I asked, and to be honest I am beginning to feel a bit silly. All week I have been performing this "reality check" in the hope that it will become so ingrained in my mind that I will start asking it in my dreams too.
If I succeed, I will have a lucid dream - a thrilling state of consciousness somewhere between waking and sleeping in which, unlike conventional dreams, you are aware that you are dreaming and able to control your actions.
Once you have figured this out, the dream world is theoretically your oyster, and you can act out your fantasies to your heart's content.
Journalistic interest notwithstanding, I am pursuing lucid dreaming for entertainment. To some neuroscientists, however, the phenomenon is of profound interest, and they are using lucid dreamers to explore some of the weirder aspects of the brain's behaviour during the dream state. Their results are even shedding light on the way our brains produce our rich and complex conscious experience.
It's a central issue in the study of consciousness. In 1992, Gerald Edelman at the Scripps Research Institute in La Jolla, California, proposed that there are two possible states of consciousness, which he called primary and secondary consciousness.
Primary consciousness is the simple subjective experience of sensory perception and emotions, which could be applied to most animals. It's a state of "just being, feeling, floating", according to Ursula Voss at the University of Frankfurt in Germany.
The mental life of your common or garden human, however, is a lot more complicated. That's because we are "aware of being aware". This allows us to reflect upon ourselves and our feelings and, in an ideal world, make insightful decisions and judgements. This state, dubbed secondary consciousness, is thought to be unique to humans.
"When you're awake, you have both primary and secondary consciousness. Secondary consciousness is that reflective awareness that determines a great part of waking consciousness," says Voss.
Pinning down how our brain produces these two, subjective, states of consciousness is a tough challenge, because it's difficult to isolate the different aspects of consciousness in fully awake subjects from other neural processes unrelated to awareness.
Which is where dreams come in. When we dream, we experience events (albeit imagined) and emotions but, crucially, we lack certain aspects of self-awareness that we normally feel when we are awake, particularly those involved in the rational reflection on what we are experiencing. You could easily see an outrageous event - a fluorescent pink kitten flying past on golden wings, to name but one - without batting a dream eyelid.
"If we can accept really weird and bizarre events as perfectly normal happenings, that means there's something wrong with our reflective, rational consciousness," says Patrick McNamara of Boston University.
For this reason, some researchers, like Allan Hobson at Harvard Medical School, believe that dreams are akin to Edelman's definition of primary consciousness. Comparing the dream state with the waking state could let us explore the way the brain generates the self-awareness of secondary consciousness.
Some headway had already been made in this direction by the late 1990s. In 1997, Eric Nofzinger and his colleagues at the University of Pittsburgh, Pennsylvania, compared the brain activity of awake individuals with dreamers using PET scans, which reveal how much energy parts of the brain are using.
The team identified three main regions that showed more activity during dream sleep, which is characterised by rapid eye movement (REM). The areas were along the midline of the brain, the insula and the left amygdala. Together, these regions are thought to be involved in motivation and reward mechanisms, and processing emotions, which Nofzinger reckons might explain why dreams are often so emotional.
Surprisingly, given the irrationality of the dream experience, many of the frontal areas of the brain involved in advanced cognition such as reasoning and forward planning were also active in the dreamers. But there was one notable exception: the dorsolateral prefrontal cortex (DLPFC) was remarkably subdued in REM sleep, compared with during wakefulness. To Hobson, that strongly suggests that this particular area, above other frontal regions, is crucial for the critical reflective awareness present in waking, and therefore secondary, consciousness.
Could this one brain region alone explain our secondary consciousness? It's here that lucid dreams enter the picture. With their increased self-awareness, lucid dreams share certain aspects of secondary consciousness, so researchers are now vying to observe what happens in the brain when someone "wakes up" within their dream, and whether they exhibit any further signatures of consciousness. "It's a very interesting leap because it can show you exactly what occurs if you jump from limited consciousness to very high consciousness," says Victor Spoormaker of the Max Planck Institute of Psychiatry, Munich, Germany. "This should be one of the main themes of lucid dream research."
Lucidity on demand
Voss and her colleagues made tentative steps towards using lucid dreams to study consciousness in 2009. She trained a group of students to become lucid dreamers using a number of tips and tricks.
Once they had "woken up" within their dream, the subjects were then asked to signal to Voss that they were lucid by moving their eyes in a previously agreed pattern, which was measured with an electro-oculograph. "We have no other way of knowing they're really in a lucid dream," says Voss. "It's a great effort to make these eye movements because normally you're in that dream and you're busy with other things; you don't want to communicate with the outside world." At the same time, Voss used EEG - a cap of electrodes placed on the scalp - to record their brain activity.
Unfortunately, the team only managed to capture three lucid dreams, an indication of just how tricky they are to study. But it was enough to reveal a couple of intriguing differences between the lucid and non-lucid dreaming brain that may contribute to the secondary state of consciousness.
Firstly, the team observed an increase in a specific brainwave - oscillating at 40 hertz - in the frontal regions during the lucid dreams compared to the non-lucid dreams, which tended to have slower brain waves. They also found greater synchronised activity between the frontal and parietal regions of the brain than in normal REM sleep, though less than would be expected in a fully awake subject. Importantly, the overall brain activity was still significantly different to the waking state, meaning the subjects couldn't have been awake and simply pretending to lucid dream.
What was the DLPFC up to? If it really were key to the self-awareness of secondary consciousness, you would expect it to "light up" during the lucid dreaming state. Unfortunately, EEG is not sensitive enough to measure the neural activity in such a small, specific area.
However, preliminary work by Michael Czisch at the Max Planck Institute of Psychiatry in Munich, Germany, hints at the answer. He used high-resolution fMRI scans to investigate the brain state of lucid dreamers. Although the results are currently being peer-reviewed, so many of the details are still under wraps, Czisch has hinted that the scans again reveal highly coordinated activity in the frontal regions of the brain, and also in the parietal and temporal zones, once the dreamers became lucid. The DLPFC was also more active than in a usual REM dream - providing tantalising evidence that it really is a crucial ingredient of secondary consciousness.
The million dollar question, of course, is how these specific patterns of electrical activity could give rise to our conscious experience. The DLPFC's role certainly makes sense, given laboratory studies that have shown it retrieves and analyses information in our working memory, and that it plays a key part in decision making.
What of the other signatures of lucidity?
The coordinated neural activity may help the various brain regions communicate more effectively, "binding" together all the different thoughts and feelings being processed separately across the brain into a single unified experience, which we perceive as "the present". One might expect more binding - and therefore greater synchrony - in secondary consciousness compared with primary consciousness, simply because the experience is so much richer, combining analytical thoughts as well as sensory perceptions and emotions.
The specific frequency of much of the neural activity in the frontal areas - 40 hertz - is also significant. Slower frequency brain waves usually dominate in sleep, whereas 40 hertz waves are more characteristic of the waking state, suggesting secondary consciousness will only emerge if the relevant neurons are communicating at a fast enough rate. Hobson likens it to "turning up the volume" in the brain.
These experiments in lucid dreaming, few though they currently are, may have wide-reaching implications in clinical situations, particularly in the study of mental illness. "When you're a schizophrenic, you're in primary consciousness really," Voss claims. "What you're lacking is reflective awareness; you cannot distinguish between reality and your hallucinations."
On this basis, Voss wonders whether it might be possible to stimulate the necessary regions in schizophrenic patients to help them achieve greater lucidity in their waking life. The work might even suggest ways for healthy people to enjoy lucid dreams. "Wouldn't it be nice if you could get somebody in REM sleep to become a lucid dreamer just by stimulating his brain?" says Voss. "No one's tried this before."
Luckily for me, I have been able to make my first foray into this strange state of consciousness without any artificial stimulation. I'm happy to report that on a sunny morning over the Easter weekend, I had my first lucid dream. It lasted all of a few seconds, and I was merely able to consciously twirl on the spot, but I woke up excited and happy. With the whole dream world now open to me, let's just hope this is only the start of my lucid life.
Edited by: Lawyer Asad