How I Think Sleep Works

Here's how I think sleep works. Much of it is my own unproven ideas. Of course, as any pure scientist would, I'd vivisection patients just to test if they're true. But seeing that is not possible, I leave my theories open to skepticism.

Agitated states

During the waking period, our brains processes sensory inputs. Some of these stimuli are novel or intense to a sufficient threshold to require further processing. For example, if we meet a familiar friend on a daily basis and they behave in the way we are accustomed to, they tend not to replay in our sleep unless something remarkable involving them happened. Whereas meeting someone of interest for the first time we notice certain mannerisms and inflections in voice that are peculiar to that individual. We don't know right away how to feel about every detail, so in the course of a nights sleep, bits of earlier conversation and scenes play in our heads until we develop a feel for this new person.

Novel or intense stimuli may evoke strong emotions that need to become associated with past experiences or categorically shelved in the memory banks. So the next time we experience something similar, we react to it in a way that aligns with past experiences. I speculate areas of the brain become agitated from these stimuli and remain in an unusable state until processed by restorative sleep.

My naive guess is that certain regions of the brain remain in an agitated state until the sleep process reaches a memory phase. This would be in a late stage of sleep associated with longer periods of rapid eye movements (REM), around the third cycle. Each cycle lasting two to three hours, so roughly in the seventh to ninth hour of sleep.

In the non-REM sleep periods that occupy most of early sleep, your body makes physical repairs. Rebuilding muscles, tissues, bone, making rounds with immune system. It makes sense that these everyday demands on our body ought to be prioritized. The REM periods that occupy late sleep are for higher level brain activity like memory and emotions.

Why do we need to sleep?

So imagine a brain with agitated areas associated with remarkable events that happened during the day. It's like they get added to a queue to be sorted and organized when sleep reaches its late stage. If you don't get those hours of long REM sleep, they remain in the queue and stay agitated the next day. Leaving these agitated areas reduces the processing efficiency of the brain. It's like putting traffic cones around road work that is unfinished, making the traffic around it move slowly. You're slower to react. You feel like your head is in a fog. It's hard to focus. You just don't perform to your best.

In order to alleviate these problems, your brain ought to get enough sleep to sort through the days events. New experiences need to be put in their proper place.

To process a new event, your brain can strengthen and weaken past associations or create new ones. Imagine the agitated area as a pipe socket that is unconnected to the system of pipes that represents the brain's network of associations and memories. In order to fit that socket, the piping must be disconnected around it and new piping built into and out of that juncture.

If the new socket leaves the flow through the pipes unchanged, now there is an additional socket and the past associations have been strengthened. The new event is associated with other events along that pipe. However, if the socket is bent in a new direction, that means an old length of pipe must be removed and a past association is weakened while a new association is created.

Until the new memory in the agitated zone is processed and connected to the memory network, brain activity must either detour around that work zone or go through it slowly. This is why it's especially necessary to get adequate sleep when learning or experiencing new things. Your brain will have more of these memories to process and will be sluggish if these agitated areas are not repaired.

What is dreaming?

Usually, these memory processing tasks are done at a subconscious level while we sleep and we are not aware they are happening. Dreaming is the phenomenon of having some conscious awareness of the process as it is happening.

First the new memory is replayed. The brain loosely shuffles it to a general category and calls up past memories that have an emotional semblance to the new memory. I want to emphasize this is an emotional association, not a logical one.

While we are awake, our conscious brain wants to analyze new inputs logically. It is like in calculator mode, takes inputs and figures out a solution. While this may be an objective and good approach, its downside is it is time consuming and resource intensive. We do not have the computational power to respond to every situation this way. Or else we'd have to evaluate friend and family every time as if they were strangers.

The purpose of memory and emotion is that we have a hard-wired association that bypasses logical computation to tell us if something is good or bad, how we ought to react to it without having time to think. If a stranger lifts up your boy and walks away, you may feel scared and protective. Whereas if your husband does, you may feel comforted and relaxed. You can react appropriately without having to think.

When we sleep, the brain tries to hard-wire emotional responses into our memories. Sometimes in ways our conscious brain would have difficulty comprehending because there may not be a logical sequence that relates two memories. We'd have to think how we feel emotionally about disparate memories to uncover their relevance to each other. And we can't ascertain logically what this relevance is, because it is subjective to each individual.

A dog and a bear to one person may mean fear and danger, while to another it may mean companion and comfort. There is no objective proof why two memories are related emotionally. Nevertheless, the more we understand how we react emotionally, the more clearly we may notice patterns.

When we are dreaming, we are viewing the memory-sorting process as it is happening. The reason why things happening in dreams don't feel strange while we are in them, is in the dream we are experiencing the associations emotionally. But when we recall it upon waking the plot of dreams often makes no sense... because when we wake up our brain switches over to logical thinking and the emotional meaning drops out so we don't understand the associations.

Dreams and their meaning

Dreams talk through emotions. The way a sentence is a sequence of words that represent meanings, a dream is sequence of memories that represent emotions.

Imagine your life played out on a video screen before you, and you get to jump to any time and pick out the moments when you were excited, or nervous, or in love, or angry. That's like what happens in a dream. A new memory that needs to be processed draws an emotional response.

Imagine one of these emotions sitting in a chair in front of this video screen with the remote control, selecting the moments that it was in. Oh yeah, I was in that one. When you wet your pants in second grade. When you showed up with your fly open to your prom date. When you asked that girl from work out and didn't see the man next to her was her boyfriend. I was there. Yep, that's me. So one dream sequence is the highlight reel that stars Embarrassment, who reprises his role in the new memory.

Maybe Jealousy and Regret show up for this new memory. Happiness and Pride take one look at this memory and go, nope that's not my thing, I want nothing to do with this event. So Jealousy sits in the viewing chair and looks at this new memory and sees where she played a role. She knows she's not the only emotion in this scene, but a large part of the spotlight is on her. So she skips through the life video to moments that she showed up in similar ways. That is so me, she laughs, oh good times!

Why is it so hard then to figure out the meaning of dreams, if they are simply emotional associations? Shouldn't we be able to tell how we feel about our past? Well we don't always know how we feel, and when we do, we don't think too hard about them. With the straightforward to associate ones we wouldn't have much to dream about. You might even be able to figure it out while you were awake. So they'd be short easy jobs that would go unnoticed. It's the beige vague and neurotic emotions that give us enough trouble to require these long dream sequences during sleep that we remember.

Does time slow down in dreams? Can we sense the future?

Why is it that we can dream a long sequence of events explaining a very brief disturbance that wakes us? It's almost as if time slows down in the dream, or we have some supernatural premonition that something is going to happen. This is hardly the case. I have a simple explanation for this time warping phenomenon.

While you are dreaming, suppose a disturbance wakes you. The disturbance triggers a new agitated zone in the brain that takes priority in the processing queue. So while you're dreaming about your vacation on the beach, suddenly the waves get taller and rise over the skyscrapers and then you tip over in your chair and wake up. How did the dream know you were going to tip over??? Do you have supernatural powers -- no.

What happened was, your brain was in the middle of dreaming about the beach when the sensation of tipping over alarmed your body to start to wake up. As you're pulling in memories associated with the beach, your brain prioritizes this new memory of tipping over. It entered into your dream sequence and started pulling out associations with fear and danger associated with falling. As the beach memories are coming in the tipping over associations are also coming in at the same time, and your dream combines them.

Dreaming vs remembering dream

Okay, but why did it last so long in the dream when the tipping of the chair happened in an instant? Because when you are dreaming, you aren't actually replaying the entire memories. You are simply linking them together. It's like computer programming with reference pointers to objects, rather than reproducing the object each time. I can remember the feeling of an entire autumn afternoon by a lake, without actually thinking about it for an entire afternoon. Remembering the feeling only takes an instant.

So of course, when two memories are associated, the linking of two memories takes only a brief moment even though one or both memories may be of very long events. It is only when we wake up and play each memory that the dream appears to have taken a long time.

Let me say this once more. It is only in remembering the dream that we experience length of time. The dream itself is a sequence of compact memories that occupies very little time. It only happens after we wake up from a disturbance that we fill in the events that happened in those memories. After we wake up, we have all the time to do that. As we remember the dream, we feel like the brief moment it took to associate two memories lasted the same length of time as the content of the memories.

It's like the difference between arranging your favorite music CDs on a shelf, and playing them one after the next on the stereo. You know what the songs sound like on the CDs without having to play them all, and you know how they make you feel. You can sort CDs just by looking at the spines and it takes a few seconds. That's like the dream.

But if you wanted to actually experience the sounds and the feelings of the music in the CDs, you'd have to play them for several hours. That's like remembering the dream.