You have been entrusted with the care and feeding of the most extraordinary and complex creation in the universe. Home to your mind and personality, your brain houses your cherished memories and future hopes. It orchestrates the symphony of consciousness that gives you purpose and passion, motion and emotion.
But what do you really know about it?
Your brain and spinal cord make up your central nervous system. Together, they control your body -- but it's the brain which is Commander-in-chief.
Here, in this article, explore with me, the creation that your brain is!
Okay, so your brain is wrinkled, soft and a little wet. It doesn't look like much. But it's made of more than 10 billion nerve cells and over 50 billion other cells and weighs less than 3 pounds! And it's the most extraordinary thing that you could possibly imagine! It monitors and regulates unconscious bodily processes like breathing and heart rate, and coordinates most voluntary movement. It's the site of consciousness, thought and creativity!
Different parts of your brain do different things. Some areas receive messages from sense organs, others control balance and muscle coordination, and still others handle speech, or emotion, memories, or basic motor skills, or complex calculations. You may think your heart is where you feel emotion, but it's really your brain. You may think your legs take you down the street, but it's your brain instructing the muscles in your legs to move. Your eyes may take in light and an image may be projected onto the pupil, but it's your brain that interprets what you see...you get the picture.
The brain contains a staggering one hundred billion nerve cells, or neurons. As Helen Phillips in her new scientist article on brain puts it – “The complexity of the connectivity between these cells is mind-boggling. Each neuron can make contact with thousands or even tens of thousands of others, via tiny structures called synapses. Our brains form a million new connections for every second of our lives. The pattern and strength of the connections is constantly changing and no two brains are alike. It is in these changing connections that memories are stored, habits learned and personalities shaped, by reinforcing certain patterns of brain activity, and losing others “.
The Human Brain Atlas
Let’s start first with the atlas of human brain. There is a very good resource for those who are somewhat more medically inclined from the Michigan State University – Brain Biodiversity Bank. There’s even a human brain screensaver there, though I can’t imagine your average Joe downloading this, but still here it is.
How the Human Brain Developed
Manfred Davidmann talks about the development of human brain through its evolutionary stages. The brain has been evolving into a more complex organ throughout the evolution of humanity, indeed throughout the evolution of life itself.
Davidmann puts it as – “We slowly ascended from lower life forms to what we are today, by a process of natural selection from randomly occurring changes. Each change had to prove its worth by surviving the continual battle for existence, being against being, species against species and this process has gone on for many millions of years”.
Basically the current understanding of science has it that we really have 3 different kinds of brains (or layers) which evolved during the course of our rise from the slime… Basically, these are categorized as:
- Reptilian Brain: this is the innermost part or layer and it’s the oldest and the most primitive part and is sometimes also known as hindbrain. The reptilian brain appears to be largely unchanged by evolution and we share it with all other animals which have a backbone. This brain layer controls body functions required for sustaining life such as breathing and body temperature.
- Mammalian Brain: Also know as the mid-brain, this was next layer to evolve. This was an enormous evolution over the primitive reptilian layer. The mammalian brain contains organs for automatic control of body functions such as digestion, the fluid balance, body temperature and blood pressure as well as for filing new experiences as they happen and so creating a store of experience-based memories and most importantly (in my opinion) for experience-based recognition of danger and for responding to this according to past experience. And for some conscious feelings about events.
- Human Brain: And the mammalian brain became the human brain by adding the massive grey matter (neocortex) which envelopes most of the earlier brain and amounts to about 85 per cent of the human brain mass. This massive addition consists mostly of two hemispheres which are covered by an outer layer and interconnected by a string of nerve fibres. It is also called the forebrain.
For those who would like to delve deeper, here is a good resource on the net for unfolding history of brain through the ages.
Comparison of the brain and a computer
Most interest has been focused on comparing the brain with computers. We have seen enough science fiction movies or novels or articles, comparing human brain to a variety of computers. A variety of obvious analogies exist: for example, individual neurons can be compared with a transistor (although a neuron's computing power is probably closer to a simple calculator than a transistor, and the specialized parts of the brain can be compared with graphics cards and other system components. However, such comparisons are fraught with difficulties.
Perhaps the most fundamental difference between brains and computers is that today's computers operate by performing often sequential instructions from an input program, while no clear analogy of a program appears in human brains.
In addition to the technical differences, other key differences exist. The brain is massively parallel and interwoven; whereas programming of this kind is extremely difficult for computer software writers (most parallel systems run semi-independently, for example each working on a small separate 'chunk' of a problem).
The closest to the equivalent would be the idea of a logical process, but the nature and existence of such entities are subjects of philosophical debate. Given Turing's model of computation, the Turing machine, this may be a functional, not fundamental, distinction. However, Maass and Markram have recently argued that "in contrast to Turing machines, generic computations by neural circuits are not digital, and are not carried out on static inputs, but rather on functions of time" (the Turing machine computes computable functions). Ultimately, computers were not designed to be models of the brain, though constructs like neural networks attempt to abstract the behavior of the brain in a way that can be simulated computationally.
The human brain is able to interpret and solve problems that are not formalized (strong AI), whereas the computer with current software and current hardware is only able to solve formalized problems (weak AI), a human can understand context in an arbitrary text, something even the most powerful and best software is not able to discern (as of 2008).
The computational power of the human brain is difficult to ascertain, as the human brain is not easily paralleled to the binary number processing of today's computers. For instance, multiplying two large numbers can be accomplished in a fraction of a second with a typical calculator or desktop computer, while the average human may require a pen-and-paper approach to keep track of each stage of the calculation over a period of five or more seconds. Yet, while the human brain is calculating a math problem in an attentive state, it is subconsciously processing data from millions of nerve cells that handle the visual input of the paper and surrounding area, the aural input from both ears, and the sensory input of millions of cells throughout the body.
Wikipedia has a great section on this approach and can be accessed here.
Oh, by the way, have you ever tried this trick? (note you might need to click on the image)
If your eyes follow the movement of the rotating pink dot, you will only see one color, pink.
If you stare at the black + in the center, the moving dot turns to green.
Now, concentrate on the black + in the center of the picture. After a short period of time, all the pink dots will slowly disappear, and you will only see a green dot rotating.
It's amazing how our brain works. *
Was this Interesting? Watch out for my entry on human dreams and their exploration!
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