New research on dreams has shown striking similarities between brain activity during wakeful visual processing and brain activity during our dreams.
Dreaming is a brain function that continues to intrigue scientists and psychologists alike. They have long speculated what purpose these elaborate visions play in our waking lives, and how our brain is affected throughout. Now,recent research in the field allowed scientists to record activity from within the brain for the first time.
The study, published in the journal Nature Communications, shows that brain activity during dreams is strikingly similar to brain activity during waking life when we process new visual images— essentially, the brain “sees” dreams.
When we see things while we’re awake, our eyes and brain collaborate to gather and process the information in our visual fields and give it meaning. When we dream, our eyes move in rapid, jerky movements (REM sleep) that are associated with increased brain activity. However, scientists still don’t thoroughly understand the function of these eye movements during sleep and dreaming – a question the new study sheds light on.
The findings were made possible by recent advances in subdural implants. Thanks to modern technology, epileptic patients now have the option to get electrodes planted directly onto the surface of their brains as opposed to having electrical impulses recorded through the scalp. The implanted electrodes can pinpoint the source of epileptic activity with great accuracy and even control epileptic attacks with pulses of electricity. Because the electrodes happen to be planted in the temporal lobe — the brain region associated with visual awareness — the Tel Aviv University investigators were able to study dreams in a way never possible before
Researchers compared the brain activity of the epileptic patients across three different settings, including REM sleep, wakeful eye movements in darkness (no visual processing), and wakeful fixed-gaze visual processing (no eye movements). By comparing the brain activity in these stages, the researchers wanted to test whether brain activity during sleep related more to physical movement, or the processing of visual information.
The results showed that, during REM sleep, the brain activity was most closely resembled visual processing during wakefulness. This suggests that our rapid eye movements during sleep are linked to visual processing rather than just physical activation or movement. Therefore, REM sleep doesn’t simply reflect motor discharge in the brain— an internal copy of a movement-producing signal—rather, it indicates the participants were likely to have been actually seeing and processing dream images. This detailed processing of our dream images implies that rapid eye movements may actually regulate our brain activity during sleep.
While much remains unknown about dreams, most scientists hypothesize that they have important functions in waking life. It’s a chance for our brains to process content that either consciously or unconsciously influences our wakeful states— we deal with the issues that need to be mentally resolved to maintain our psychological well-being.
Scientists are still working to answer various questions about our dreams and their physical and psychological functions, but being able to analyze dreams from within the brain may open a new realm of discovery.