“The study of microdreams offers unique possibilities for developing experimental methods to clarify how and why images are formed.” (Nielsen, 2017)

Part 1. The Memory Sources of Microdreams

Photographee.eu
Source: Photographee.eu

An exciting new paper published in Neuroscience of Consciousness zooms in on a new avenue for dream research: The "microdream." These are short dream snippets, usually less than 1 second long, which sneak into your thoughts as you doze off to sleep. Researcher Tore Nielsen looks more closely at what these microdreams are made of and how they can be used in the study of dreams.

Many of us have had the experience of lying in bed or sitting at a desk, thinking about something but feeling slightly sleepy, when suddenly we "come to" as a fleeting image has crossed our vision or a bizarre thought skips through our mind. Most of the time, we simply disregard these fleeting images, and either re-focus on the task at hand or allow ourselves to slip more steadily into slumber. In fact, given their very brief and unexpected nature, it can be difficult to describe microdreams, even if you do recall them.

Training in self-observation likely improves the ability to recall microdreams, just as keeping a dream diary improves recall of morning dreams over time. One such technique for practicing microdream observation is the “upright napping” procedure. This is one technique Nielsen used in his research, and through careful observation, several consistencies in the nature of microdreams became clear.

First, microdreams often contain some subtle sense of movement, that distinct feeling of falling asleep — a sense of the body slightly shifting or sinking in space. This could be the feeling of muscles in your body relaxing in unison.

Second, microdreams draw from memory; both recent and more distant past memories are incorporated into microdream images. This is important.

We know that dream images are re-creations from memory, and one aim of research is to identify how and why certain memory traces are selected in the creation of a dream. We call these a dream's "memory sources." However, attempting to identify the memory sources in a nighttime dream can be a laborious and complex process, because nighttime dreams can be quite long, and each image may contain multiple memory associations. Further, discerning the exact source of an image is made more difficult by the often bizarre and metaphorical nature of dreams.

But with microdreams, the memory sources are fewer, and more readily accessible. According to Nielsen, “because microdream images are brief and occur in such close proximity to wakefulness, attention can be directed quickly to identifying their source memories.”

In a prior study in the laboratory, one participant was signaled during 31 brief sleep onset dreams (just as the participant was falling asleep), and the participant was able to identify on average 2 to 3 memory sources for each fleeting image. For instance, in one microdream, he incorporated 3 "pets" from memory — a pet cat from recent memory, a pet rabbit from 12 years ago, and a teddy bear from 15 years ago.

This example demonstrates one common quality of dreams and microdreams: The tendency of images to draw on both recent and more distant memories from the past.

Here is a detailed example of a microdream recorded through self-observation, while sitting with elbow upright on a desk, and chin resting on hand:

     “I see a small blue-and-white object far off to my left. Its colors are very bright and form a swirled pattern. It suddenly and unexpectedly flies towards me, horizontally but with a slight arc. It was as if someone had thrown it at me. Close to me it is about the size of a basketball. I make a quick, reflexive movement with my left arm as if to strike or intercept it. For an instant I feel a sensation on the upper part of the elbow and forearm as the ball makes contact with me….”

It’s worth noting that this entire sequence occurred within the space of one second. (Again, it likely takes some training in self-observation to recall and report these mini experiences in such detail.) But despite its brief nature, this sequence of images was found to incorporate several memory sources. The initial fleeting image of a blue/white circle is accompanied by the physical sensation of nodding off, and if you remember, this image occurred in a position with the chin propped up by the arm, so there was a sudden muscle jerk in the arm at sleep onset. At this point, the blue/white circle becomes a larger sphere that rapidly approaches and makes contact with the dreamer’s arm. Nielsen notes that this image is similar to a recent memory of striking a volleyball two days prior.

So, we see two sources of imagery: The arm sensation causes the circle image to contact the arm, and the memory of playing volleyball contextualizes this image, changing it into an appropriately sized sphere: "I see a blue/white circle, I feel my arm twitch, oh it's a volleyball hitting my arm, much like it did the other day." Perhaps if the dreamer had gone surfing instead, the blue/white circle would have transformed into a wave crashing on his arm.

This "sense-making" is a constant process of the mind; as we move through the world (both waking and dreaming), we make sense of our current experience by drawing on similar experiences from the past.

In another example, the dreamer is lying down with three fingers pressed against the forehead, thinking about a difficult guitar chord that requires these fingers. In a moment’s microsleep, the fleeting image of twisting off a bottle cap appears, accompanied by a muscle twitch in the fingers, and an unexpected sensation on the forehead where the fingers are touching. This leads to a second fleeting image of a woman’s hand reaching toward the forehead.

In this sequence, we see a chain reaction of imagery: Waking thought (fingers in guitar chord) leads to an image (fingers twisting bottle cap) causing fingers to twitch, which leads to sensation (fingers on forehead) then projected in a new image (hand reaching to forehead).

[Note: Muscle twitches are quite common during sleep: When we dream of certain actions, such as moving our arm or leg or speaking, they are often accompanied by real twitches in body muscle, e.g., in the arm, leg, or chin.]

Again, in this example, the mind goes through a process of "sense-making," creating imagery to make sense of experience, all within the space of milliseconds.

You can imagine how much more complex this process could be in a full-blown dream, as dream images are continuously transformed through limitless sensations and memory associations. By this token, microdreams provide a much more manageable method of studying the memory sources of imagery. 

To learn more about how microdreams are formed, see my next post, on how real-world stimuli are nearly instantly transformed into microdream images.

References

Nielsen, Tore. "Microdream neurophenomenology." Neuroscience of Consciousness 3.1 (2017).

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