By studying the brain activity of lucid dreamers under electroencephalograms (EEGs) and fMRI scans, researchers have found that activity in the somatosensory and motor cortices – regions crucial for touch and movement, respectively – show very similar activation patterns during lucid dreams to those they display when people make or imagine those same movements while awake.
Though dreams have fascinated philosophers and scientists since the dawn of history – some of the earliest written texts are dream-interpretation handbooks from ancient Egypt and Babylon – it’s only in recent years that neuroscience has begun to advance the study of dreams beyond Freudian theorizing and into the realm of hard data.
In the early 1950s, scientists identified several stages of sleep, including rapid eye movement (REM) sleep – the stage in which dreaming takes place; and in 1959, a team discovered a certain class of brain waves – ponto-geniculo-occipital (PGO) waves – which only appear during REM sleep.
Then, in 2009, an EEG study found that lucid dreams exhibit slightly different wave patterns from those associated with ordinary REM sleep – and later that year, another study proposed an astonishing theory: that REM sleep might be a form of proto-consciousness, which performs maintenance and support duty for the “full” consciousness that took over for it at some point in our evolution.
Now, as the journal Current Biology reports, a team led by Michael Czisch at Germany’s Max Planck Institute has made a new leap forward in dream research. By concentrating their research on lucid dreams, the team were able to map the neural correlates of controlled and remembered dream content:
Lucid dreamers were asked to become aware of their dream while sleeping in a magnetic resonance scanner and to report this “lucid” state to the researchers by means of eye movements. They were then asked to voluntarily “dream” that they were repeatedly clenching first their right fist and then their left one for ten seconds.
This approach has provided some surprising new insights into the ways our brains function in a dream state. By having the subjects retell their lucid dreams, the researchers were able to correlate recorded activation patterns with specific actions the subjects had “performed” while asleep:
A region in the sensorimotor cortex of the brain, which is responsible for the execution of movements, was actually activated during the dream. This is directly comparable with the brain activity that arises when the hand is moved while the person is awake. Even if the lucid dreamer just imagines the hand movement while awake, the sensorimotor cortex reacts in a similar way.
This confirms that the brain’s sensorimotor areas are actively involved in planning and executing movements in dreams, rather than just passively observing events.
What’s even more exciting is that, in light of other new technologies like the thought-video recorder, it looks like we may be able to record and play back our thoughts and dreams within the next few decades.
I think this research reflects an even more fundamental shift in thinking about neuroscience, though: as we unravel more and more of the neural correlates of phenomena like sleep and consciousness, we’re coming to realize just how vast a chasm yawns between scientific data and subjective experience.
Before long, it’s going to become essential for scanners and volunteers to be involved in the same continuous feedback loop – one in which the subjects can watch, in real time, the neural correlates of their thoughts and feelings from moment to moment, and adjust them accordingly to produce useful results.
Ambitious? I guess so. But a guy’s gotta have a dream.