Can we understand, in real time, what is unfolding inside the dreaming mind?

Exploring a dream while it unfolds has always seemed impossible, but a team led by Karen Konkoly and Delphine Oudiette has shown that this previously inaccessible territory can become measurable and even communicable. The study, developed through an international collaboration, reveals that lucid dreamers (people who are able to recognise that they are dreaming while the dream is occurring) can transmit reliable information in real time, directly from within the dream. This opens new possibilities for studying the mind during sleep.

Until now, research on dreams depended almost exclusively on what people remembered upon awakening, which resulted in fragmented, distorted reports with poor temporal precision. To overcome this limitation, the researchers worked with participants who had experience in lucid dreaming. Before falling asleep, these volunteers learned a small “vocabulary” of signals they could perform within the dream: specific patterns of nasal breathing and small contractions of facial muscles. Each pattern corresponded to a simple piece of information, such as indicating whether the “dream eyes” were open or closed, or whether they were seeing visual content at that moment.

While they slept in REM sleep, these signals were recorded through respiratory sensors, electromyography, and electroencephalography (EEG). This made it possible to relate, with high temporal precision, what the volunteer communicated from the dream to the brain activity recorded at that exact moment.

The results revealed that closing the eyes inside a dream does not function the same way as closing the eyes in waking life. When we are awake, closing the eyes produces a clear increase in alpha activity in the EEG, a well‑known pattern. But in the dream, this did not occur consistently. Furthermore, the act of “closing the eyes” in the dream caused dream imagery to fade only about half the time; in other cases, participants continued to see the dream environment even with the “dream eyes closed.” Additionally, in the three participants who experienced both moments with visual imagery and moments without imagery (complete darkness) during the dream, episodes without visual content were associated with higher levels of alpha activity, suggesting a relationship between brain rhythms and the mechanisms that support visual experience in dreams.

Taken together, these data show that perception within the dream follows its own rules and does not simply replicate waking‑state patterns. They demonstrate, for the first time, that it is possible to study dreams directly as they are happening, a methodological advance that may transform the science of sleep and consciousness. This study was published in the scientific journal Journal of Cognitive Neuroscience, in the article Using real-time reporting to investigate visual experiences in dreams, as a part of research project 391/20 - Illuminating the dreamer's perceptual experiences, supported by the Bial Foundation.

ABSTRACT

Neuroscientific investigations of human dreaming have been hampered by reliance on dream recall after awakening. For example, a challenge of associating EEG features with post-waking dream reports is that they are subject to distortion, forgetting, and poor temporal precision. In this study, we used real-time reporting to investigate whether one of the most robust features of the waking visual system, increased alpha oscillations upon closing one's eyes, also applies when people dream of closing their eyes. We studied 13 people, four with narcolepsy and nine without, who experienced many lucid dreams-they were aware they were dreaming while remaining asleep. They reported on both their dream experiences (visual percepts present/absent) and dream-eyelid status (open/closed) using a novel communication technique; they produced distinctive sniffing patterns according to presleep instructions. We observed these signals in respiration recordings from a nasal cannula. These physiological signals enabled analyses of time-locked neural activity during REM sleep. We recorded 150 signals over 19 sessions from 11 individuals. Robust increases in alpha power were not found after signaled dream-eye closure. Remarkably, the experience of eye closure while dreaming was associated with fading visual content only about half the time. Comparing the presence versus absence of visual content was possible only in three participants, who showed increased alpha power in association with a momentary lack of visual content. Enlisting dreamers to actively control and report on ongoing dream experiences in this way thus opens new avenues for dynamic investigations of dreams-the illusory perceptions that haunt our sleep.