Database And Brain

I found many people are looking for an easy way to memorize something.

I am a guy who needs a nap to memorize well. This has been said that it is just an excuse of my nap in a class.

Here's a logical explanation why a sleep lets you memorize well. It is again from the talk.

It is popular to make a test about memory to see how an animal reacts when a blow gets in your eyes. When you do, you close your eyes, don't you.

After making an animal listen to a sound, the animal gets a blow in its eyes. Sound, Blow, Sound, Blow, repeatedly. Then, when the animal listens to the sound, the animal will close its eyes. It is the Pavlov's conditional reflex.

It is memory that makes the animal understood, "a blow is coming soon after the sound". There is nothing to do with hippocampus at this stage.

Then, we put an additional step. We shed light on the animal at the same time when making the sound. Later, we do the previous test, Sound-Blow.

And then, against the light, an animal closes its eyes, and waits for a blow. For this memory, hippocampus is necessary.

Both look the same. But there's a big difference. It is that Light is apart from Sound and Blow in terms of time. Putting things, which are apart in terms of time, together is very difficult.

This is syllogism. Light and Sound. Sound and Blow. Then, Light and Blow. This kind of syllogism can't be done without hippocampas.

Let's look back the mouse test(please refer to "Sleep to Memorize").

The locations, A, B, C, and D, are distant from each other. But in a REM sleep, ABCD is compressed alltogether. Then, some information, which is apart from each other in terms of time, can mean the others in a series.

So this kind of "sensing" happens when sleeping.

He says well-reorganized-information-in-sleep is limited. So try hard before you sleep!

This is translated from this page, titled "Things you didn't understand may get clear when sleeping".

「海馬(hippocampus)」 is the book by the researcher, Yuji Ikegaya.

Yuji Ikegaya is a leading reseacher of brain, particularly in hippocampus. This is a talk between Shigesato Itoi, the famous ad copy writer, with him.

The topic is about sleeping.

While you are awake, about 30% of neurons are active at some point in time.

While you are in REM sleep, only 30% of neurons are active, but in non REM speep, almost 100% of neurons are active.

While you are in REM sleep, you would have a dream.

Our brain does two simple things.

1. Garner information
2. Memorize information

In computer, it is the same thing. But our brain can't do that at the same time. First, garner information, then memorize it. Garnering is done when you are conscious, awake or in REM sleep, while memorizing is done in non REM sleep.

At times, I see he has great expertise/experiences in computer science. He have tried a crazy test. With a 6-legs-computer, he broke one leg, then observed how it can evolve its program to make it work. According to him, in the process, the computer made similar trials as human do in a dream.

I am a specialist of hippocampus especially in CA3. CA3 garners information while you are awake, and does a very interesting activity in non REM sleep. It is a compression of information.

Then, he explains about it refering to an experimentation with a mouse.

the following image is from the talk page

He let a mouse walk in a place. Neuron A becomes active only at place A. Neuron B only at place B, and so on. So he can get where the mouse is without checking it as long as he is watching the monitor.

Then, he let the mouse take a sleep, then sees it is having a dream in the same order. Suppose the mouse moved A->B->C->D, it is having a dream A->B->C->D. So what happens in non REM sleep?

It is, again, A->B->C->D, but, at a tremendous speed. About 100x faster. Besides, they are compressed.

And then, the compressed information is sent back to cerebrum and is memorized permanently.

It is interesting that our brain has two types of memory, temporal and permanent. And to be memorized permanently, a temporal memory has to be processed by CA3.

Locations are different or only forms to be memorized are different?

I read that a permanent memory in our brain is never deleted. So what about temporal memory? If they are not deleted, our brain is supposed to have duplicated information.

I also read that, while having a dream, our brain randomly put memories together. The process must be required to determine the exact place to store information permanently.