What is the strength of the brain?
Date 27 December 2011, kategori Artt Bilimsel, author Güneþ Tan

You know there is a common question around us: Our brain actually does not work with full capacity, if it works with full capacity what happens, what else it can do? I’m sure you thought of this case many times. If you’d like we can bring a scientific point of view to this subject and let’s look at Gresham College, Professor Keith Kendrick statements: “To understand this situation, let’s review some things which is made of human. For example, the entire telephone system of our planet … If it is considered all the world’s phones, and all the telephone wires (there are more than 6 billion people on our planet) and in one day, trillions of messages sent to the connections and it is even not the same mixed action in the brain.

Now assumed that all the phone lines are broken and disconnected in a country, how much time do we need to repair the whole system? One week, a month or a few years? If you answered that question as a few years, it means you start to understand with what you are facing if you injured from your brain.

Imagine a big computer for another example to understand this fact: The biggest computer – Aski-Purple, created by IBM, at the US Department of Energy is 830 square metres in size. It weighs in at a massive 200 tons. And it still only has half of the information processing capacity of a brain…

One of the characteristics of the brain which is different from a computer is its ability to comment on non-existent matters. One of the key areas that all brains have is the ability to attend selectively to something going on in the environment and pretty much ignore everything else.

Another very simple thing that all brains do, in the visual system at least, is to ensure you can work out your optics. The lens of your eye actually turns things upside-down, but we all know that we do not see the world upside down and nor, for that matter, do we imagine that other species with eyes see things upside-down. The brain is what turns the world back the right way up. It assumes that’s the way it appears, so that’s the way you experience it, but it is the brain interpreting something that’s upside-down.

So the brain is a phenomenal interpreting device and one should never forget that. It has very big ramifications, particularly when we’re talking about, for example, our witness-based judicial system. If the brain remembers something, it rewrites it, and it will rewrite it in the context of whatever’s going on at that particular point in time. If you’ve had a bad day, or another experience, they can get mixed up, and so when you lay down the memory again, it’s no longer exactly as accurate as it was when the event first occurred to you.

If we’re considering how a brain might work, of course you can look at it at a large number of different levels, all the way from genes through to the molecules of the brain and how they are released, for example, from synapses, how little networks of cells group together to perform functions, and ultimately, how when we put them altogether into the brain, how do they work in some kind of holistic function to give more than the sum of its parts, because believe you me, that is the secret of the brain. It isn’t that you just add all the parts together and you get function. The brain is doing something, or lots of things, holistically, and that’s one of the main things that distinguish it from a computer, which does not. The scientists know how important the brain is. Two-thirds of our genes are actually expressed in the brain. We really need to understand how brains work as a cohesive, communicating network of cells. As far as the highest level of communication is concerned in the brain, primarily that communication is simple, electrical impulses.

If we convert it back to language, at any particular nerve cell has many thousands of cells talking to it, saying either yes because they’re excitatory so they use a particular kind of chemical transmitter, or they’re saying no, don’t do anything, they are inhibitory input and they use a different transmitter. When there’s a balance between the “no’s’’ and the “yes’s”, it doesn’t do anything. It all cancels out. It doesn’t send any messages off downstream. However, when the “yes’s” in this particular case are occurring more frequently and strongly than the “no’s, then this fires off a “yes” message from the cell to its target down here, and then that starts the whole process on downstream. Very importantly in getting the complexity of the brain, there’s feedback, so it’s also telling the guys that are signaling to it and saying things to it, “Hey, I’m saying yes,” so there’s feedback going on as well, and this very simple system is capable of huge complexity.

What do messages mean?

Just to make life a little bit more difficult, we get conduction of electrical impulses from the cell body through the axons. It’s one way traffic as far as the nervous system is concerned, it’s only transmitting one way. When they get to the end of the road, there’s a gap between their process and their receiving cell. It’s a very small gap, it’s less than a micron, and the information is transmitted across that gap chemically. So there’s a release of chemicals from the pre-synaptic terminal at the end of the axon. These pass across the synaptic cleft, and act on various receptors to cause changes in the electrical activity of the target cell, either depolarizing it or hyperpolarising it, or so propagating the message on to the next cell. This is of course capable of infinite control.

All these simple things that I’ve so far described to you have already gathered a clutch of Nobel Prizes. They were very difficult to discover just at this level. So you’ve got recognition of the structure of the nervous system, Golgi and Cajal; you’ve got functions of neurons, Sherrington for example, and Lord Adrian; and for the chemical transmission of nerve impulses, synapses, Sir Henry Dale and Otto Loewi. There are of course many other individuals who have received prizes for their work on basic elements of functions of nerve cells. But at this stage, we know how they work. We just don’t know what it is they’re saying, that gives us experience. So what are the messages really saying? It’s a kind of huge enigma machine that’s in there that is somehow or other conveying huge amounts of complex information and it’s also giving us a conscious experience. It’s not just what they’re saying, it’s also who’s listening to them how are they interpreted? And finally of course, how do they give rise, all this electrical activity, to our perception, thought and action, things we take for granted?





If you start looking at the global activity of the brain in any detail, it may be too confusing. In the brain cortex in awaken state there are electric waves with relatively high frequency, low-voltage and asynchronous which are produced by the brain. So the cells are not able to do everything at the same time in harmony. On the other hand, when we lay down to sleep they begin to work- even at this stage electrical brain waves are still not synchronized – later when you enter the early stages of sleep there occur a dramatic change.

As a wonderful way, they become as synchronized rolling slow-frequency brain electrical waves. This is called as ‘theta’ brain waves. But not just “sleep” creates along the cortex the synchronized brain waves, activities such “learn” also creates things like that. When we learn something the brain has a global synchronized operation. It works more useful in a holistic way. Thus, the information on one side of the brain is connected to the other part of the brain.

In the brain each part works separately, but in a way they get connected and give us the experience of awareness. This is as if four different pictures become a single unique scene at the end. In another example, it may be also, many different cooks do different processes for a meal, but ultimately the product will be a single meal. At that moment “awareness” occurs.

How do the extensive networks in the brain actually work? To understand this, there is a single figure which can be created very difficult, it is to listen to the communication while they are doing something … it is not enough to listen just to one or two, listen to hundreds of them…

Until recently this technology does not become a useful state, but now during the researches by putting listening devices it become easier to get information about the systematic network information of the brain. In this study the people on the experiment is left to justify any stimulus used in this study, such as smell or looking at the different faces and in the meantime in the cortex area it was set a listening device which records the electrical outlets of a few hundred nerve cells simultaneously.

We can give ideas about how the system works, as follows: there are five million neurons which can take the smell and they have thousand different types of neuron receptors. “Olfactory bulbs have 2.5 thousand recipient’s point, which can take the information. As you can see, everything is occurred in a phenomenon speed. However, any computer is able to do that!

Many people expect to be in harmony in their brain, to be able to do everything at the same time … If we work as a team, we will solve all the problems easily. It is obvious that the brain does not use this principle. The majority of the cells are not in a positive harmony with each other! ”

http://gresham.ac.uk/event.asp?PageId=108&EventId=294





















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