疫情当下，现实版盗梦空间的真相究竟是什么?

If you've been having bizarre dreams during the pandemic, you're not alone.

Those who are sharing their #pandemicdreams on Twitter are either amazed at the peculiarity of their dreams or distressed by plots that center on death, fear and strange new worlds.

"In my dream, I called an Uber, but a hearse showed up instead. Not liking these #pandemicdreams," posted Sarah Schachner on Twitter on March 23.

"I dreamed that I encountered a duck hanging out in deep snow," wrote John Johnson in a Tweet on April 8. "I asked the duck 'if I were your chickie would you take care of me?' and the duck replied 'yes.' It was very reassuring. #pandemic dreams".

According to experts, these cryptic responses are normal. Our brains' way of understanding the stressful information we take in during the day can manifest in nightmares.

Or we might dream of past chapters in life that were less stressful.

"This [pandemic] is something that they've never experienced before," said sleep medicine expert Dr. Meir Kryger, professor of pulmonary medicine and clinical professor of nursing at Yale School of Medicine.

"And it's possible that their brains are trying to find a time when things weren't like that. It's like when sometimes people are trying to fall asleep and they can't turn their minds off. They will try to think about a time when things were better.”

Researchers still don't know why we dream, said Jason Ellis, a psychology professor at Northumbria University and director of the Northumbria Centre for Sleep Research.

But there are a few theories.

"There's the evolutionary theory that says we use dreams to try out different scenarios in a safe environment" that might be challenging or threatening in real life, Ellis said.

Another hypothesis is the memory consolidation idea, he added, which suggests that when we're dreaming, we're taking in the information we've collected throughout the day to either create new memories or sort unfamiliar information into existing knowledge that informs our reasoning.

"When we look at people's brains when they're sleeping, you can actually tell differences between when they're dreaming and when they're not. And we can certainly see that brain activity changes as a function of dreams," Ellis said.

There's another dream theory -- the mood regulatory function theory -- that says dreams are for problem solving through emotional issues that we experience.

The stress of a pandemic -- with its family, work and mental troubles -- can result in dreams that are equally upsetting, as dreams can not only help us cope but also reflect reality.

Vivid dreams may serve as coping mechanisms, or our brain's way of processing novel circumstances.

"What we do know is that it's patterns of sensory information that are being relayed in the brain. So you've got sight, hearing, touch, smell and taste. What's most interesting about dreams is that they're predominantly going to be sight-based or hearing-based," Ellis said.

These dreams mostly occur during REM -- or rapid eye movement -- sleep, our deepest phase of sleep that occurs in intervals during the night and is characterized by rapid eye movements, more dreaming and bodily movement and faster heart rate and breathing.

REM睡眠：快速眼球运动(rapid eyes movement)亦称异相睡眠   （Para－sleep)或者也叫快相睡眠，异相睡眠或快波睡眠，是一个睡眠的阶段，眼球在此阶段时会呈现不由自主的快速移动。在这个阶段，大脑神经元的活动与清醒的时候相同。多数在醒来后能够回忆的栩栩如生的梦都是在REM睡眠发生的。

"So the fantastical dreams people are reporting are most likely to be quite REM-based," Ellis said.

What's odd about some of our pandemic dreams isn't only the content of them or the fact that we're having them. It's that we're remembering them, which isn't typical -- normally, we'd forget most of our dreams shortly after waking up for the day.

Drinking more alcohol typically suppresses memories of dreams. But drinking more often can also wake us up more during that deep phase of sleep in which our brains are most active, thus making the dreams more memorable, Ellis said.

Binge watching popular and favorite TV shows with exciting stories seems like a fine idea for entertainment while we're staying indoors. And we may also may feel the urge to stay updated on the news from the moment we awake till we fall asleep. But doing these things for hours before bed can contribute to a restless night ahead, Kryger said.

We could also be having strange dreams because our routines are all out of sorts.

"Usually when we've had to go into the office or we've had to go to work, there's been a very strong structure about what time you get up and leave; we would probably put ourselves to bed at a certain time so we could get up and get ready and do all of these things," Ellis said.

Those things don't exist quite to the same degree for many of us as they had previously. Routines have suddenly become harder to establish and maintain and the motivation to go to sleep at the same time each night may be gone, which can upset the internal processes necessary for good sleep, Ellis said.

Not only have our routines changed in terms of work, but our social practices have switched as well. Since we're social creatures, we've creatively adapted to new ways of interacting with our friends and family, such as virtual dinners, movie watching and live streams on social media.

Interacting in these ways in person can be perfectly healthy. But the light exposure from screens hours before bed, no matter the purpose, can be detrimental to ensuring a good night's sleep, Ellis said.

It can be difficult to adopt positive, productive habits during these stressful times. But trying your best to still maintain good sleep hygiene can not only help ensure a good night's rest, but also prevent the development of more serious problems in the long run.

Healthy sleep habits include signing off from screens two to four hours before bed and trying to turn in at the same time each night. Turning off the news for a little while before bed can also help cut back on the anxiety that may present as stressful dreams, Kryger said.

"We know that when somebody is not sleeping very well, it creates an incredible risk for them to develop depression in the future or develop post-traumatic stress disorder in the future," Ellis said.

"So I think what we need to do right now is focus on managing people's sleep to try to prevent a lot of psychological illnesses that are going to come up nine, 10 months down the line.”