Insomnia, Memory, and Dreams

Ask insomnia sufferers what they want, and the first thing on their wish lists is “more sleep.” Or “more deep sleep”—the kind associated with feelings of rest and restoration.

I’ll go along with that. But my wish list contains a few more items.

Insomnia may impair memory, and remembering events and dreams may depend on theta activity in the brainAsk insomnia sufferers what they want, and the first thing on their wish lists is “more sleep.” Or “more deep sleep”—the kind associated with feelings of rest and restoration.

I’ll go along with that. But my wish list contains a few more items:

 

 

  1. A better memory for past events is one. My husband narrates whole sequences of his childhood as though he were reliving them again. My memories are skeletal by comparison.
  2. I’d also like to remember my dreams. My husband recalls entire movies that take place nightly in his head, but I’m lucky if I remember a snippet of a dream once in 3 weeks.

Research suggests that insomnia may have negative effects on memory, and also that the consolidation of memories for facts and events takes place largely during deep sleep, when slow brain waves predominate. Now a team of Italian researchers is claiming in a review paper that theta waves—which are slightly faster—are likewise important in the formation and recall of memories, for both waking events and dreams.

Types of Brain Waves

Day and night, neurons are firing in the brain at a mix of frequencies. When we’re alert, most neuronal activity taking place is fast, or high frequency. (Frequency is measured in cycles per second, or Hertz [Hz]). At night the brain slows down. But activity picks up again during rapid eye movement (REM) sleep. Here are the 5 types of brain activity:

  • Gamma waves, 40 to 100 Hz. Associated with intensely focused attention and effortful problem solving.
  • Beta waves, 15 to 40 Hz. Associated with a more relaxed but focused level of attention, thinking, and sensory processing.
  • Alpha waves, 8 to 14 Hz. Associated with resting, relaxation, and meditation. Also the starting point for falling asleep.
  • Theta waves, 4 to 7 Hz. Predominant during Stage 2 sleep. May also occur during very relaxed periods of wakefulness, when the mind is wandering.
  • Delta waves, 0.5 to 3.5 Hz. Predominant during deep sleep.

The mixed-frequency brain activity that occurs during REM sleep—theta, alpha, and beta—makes it look like the brain is more awake than asleep.

Theta Waves Involved in Waking Memory

Research shows that memory processing is characterized by specific waveforms occurring in memory-related areas of the brain. In particular, the Italian researchers write, the theta rhythm “seems to correlate consistently with episodic memory, . . . the ability to remember past experiences and autobiographical events.”

Memory processing involves both inner and outer areas of the brain, and EEG recordings of subjects performing cognitive tasks have shown that theta power increases in key areas during the encoding and retrieval of information. In two studies, participants were exposed to a series of words and then asked to recall them later. The authors found that (1) theta power increased only during the encoding of the items that participants were later able to recall, and (2) the amount of theta power during the encoding phase differentiated good and bad performers when it came time to recall what they learned.

Other studies have shown that theta activity increases during the retrieval of previously learned material. Still other studies have shown that a brain oscillating in theta mode before exposure to new information is primed to recall that information later on.

Theta Involvement in the Recall of Dreams

Some studies of dream recall, in which participants’ brain waves are recorded as they sleep and they’re awakened periodically and asked to report their dreams, suggest a relationship between dream recall and alpha waves. But the findings in these studies overall are inconsistent–possibly because of different study protocols.

More recent research shows that successful dream recall is associated with both alpha and theta activity in frontal areas of the brain. And, as neuroimaging studies suggest that the mechanisms underlying mental processes are similar during wakefulness and sleep, the researchers propose that it’s the relative presence or absence of theta waves that determines whether or not we remember waking events and dreams.

I don’t know if my shoddy memory is related to a deficit of theta power, or what that may or may not have to do with my predisposition to insomnia. But as long as I’m making a wish list, I’d like a better memory. In addition to more deep sleep, I think I’ll ask for more theta power, too.

Dreams Recalled: What They Say about Your Sleep

My husband is a champion sleeper. He’s also prodigious when it comes to remembering his dreams. Often his dreams are unpleasant: He’s running to catch a plane and realizes he doesn’t have his bag, or he’s shouting at a class full of students. By the time he gets to the dessert table at a party, all the chocolate (i.e. real) desserts are gone.

Still, I envy his amazing powers of recall. I’d love to have half as much access to what goes on in my head at night.

A new study in the journal Neuropsychopharmacology sheds light on why some people tend to remember dreams and others don’t. Could it explain why I remember fewer dreams now than ever before?

dreamingMy husband is a champion sleeper. He’s also prodigious when it comes to remembering his dreams. Often his dreams are unpleasant: He’s running to catch a plane and realizes he doesn’t have his bag, or he’s shouting at a class full of students. By the time he gets to the dessert table at a party, all the chocolate (i.e., real) desserts are gone.

Still, I envy his amazing powers of recall. I’d love to have half as much access to what goes on in my head at night.

Why Only Some People Remember Dreams

A new study in the journal Neuropsychopharmacology sheds light on why some people tend to remember dreams and others don’t. It has to do with activity in a part of the brain called the “temporoparietal junction (TPJ).”

The sleeping brain cannot store new information in long-term memory. But in people who dream prolifically, the TPJ—which receives and processes information from the environment—is more active at night than it is in people who rarely remember dreams. This suggests that frequent dreamers actually experience a lot of nighttime wake-ups, authors of the study say. The wake-ups are brief enough to go unnoticed, yet they’re long enough to enable the encoding of dreams into long-term memory.

Who knew there could be such a mechanistic explanation for why people like my husband have such marvelous access to their dreams and people like me do not?

Looking for Meaning in Dreams

For many years, I had two kinds of dreams: either I was doing a boring task like following a never-ending trail of breadcrumbs, or I was witnessing the horrifying crash of a plane or train. Rare was the dream that featured movie-like scenes where I was interacting with others and moving from event to event.

But then I moved to San Francisco and went on a Carl Jung kick. I became convinced that dreams had meaning and could acquaint people with hidden knowledge in their unconscious. If I could remember more of my dreams—and surely some were worth remembering–I imagined I’d find a trove of knowledge buried inside.

Together with friends, I launched a group that met once a month to interpret our dreams. The only trouble was, I had to remember a meaningful dream to have something to work with. Just how was a person like me supposed to accomplish that?

A Way to Remember

“No problem,” one of my friends said. “Everyone has meaningful dreams—you’ve just got to find a way to remember yours. As you’re falling asleep, just ask a question about a problem you want to solve—send it out to the universe—and then, every time you wake up at night, write down what you were dreaming so you won’t forget.”

Seriously?! I, a person with world-class insomnia, was now going to have to

  1. think about a problem as I was trying to fall asleep, and
  2. rouse myself enough to record communiqués from my unconscious every time I woke up at night? How exactly would I be able to get any sleep at all?!

I was obsessed by the idea of exploring my dreams, so I vowed to do whatever it took. I started writing down some of my dreams at night.

Dreams Recalled

I did remember more dreams in the eight months our group met. In fact I had one of the most memorable dreams of my life: instead of driving my car over the Bay Bridge in rush hour traffic, in the dream I was carrying the car on my back. There’s no mistaking the meaning of that! But I’m pretty sure I didn’t need that dream to know how much I hated my commute over the bridge.

Now that I’ve got my insomnia under control, I remember even fewer dreams than I did in the past. Could the fact that I now sleep more soundly–with fewer nighttime wake-ups–be part of the explanation, as the study above might suggest?

All else equal, I’d prefer to awaken to cinematic dreams like some of my husband’s, which take him to Nepal and Thailand and other far-flung parts of the globe. But we’re none of us equal in sleep and waking. If relinquishing knowledge of my dreams is a price I have to pay for better sleep and daytime stamina, I’ll stick by the choice I’ve made.

If you remember your dreams, what’s the most common type of dream you have? Have you noticed that dreaming has any relationship to the quality of your sleep?