The brain has three main parts, the cerebrum, the cerebellum, and the brain stem. The brain is divided into regions that control specific functions.
THE CEREBRUM:
Frontal Lobe
* Behavior
* Abstract thought processes
* Problem solving
* Attention
* Creative thought
* Some emotion
* Intellect
* Reflection
* Judgment
* Initiative
* Inhibition
* Coordination of movements
* Generalized and mass movements
* Some eye movements
* Sense of smell
* Muscle movements
* Skilled movements
* Some motor skills
* Physical reaction
* Libido (sexual urges)
Occipital Lobe
* Vision
* Reading
Parietal Lobe
* Sense of touch (tactile senstation)
* Appreciation of form through touch (stereognosis)
* Response to internal stimuli (proprioception)
* Sensory combination and comprehension
* Some language and reading functions
* Some visual functions
Temporal Lobe
* Auditory memories
* Some hearing
* Visual memories
* Some vision pathways
* Other memory
* Music
* Fear
* Some language
* Some speech
* Some behavior amd emotions
* Sense of identity
Right Hemisphere (the representational hemisphere)
* The right hemisphere controls the left side of the body
* Temporal and spatial relationships
* Analyzing nonverbal information
* Communicating emotion
Left Hemisphere (the categorical hemisphere)
* The left hemisphere controls the right side of the body
* Produce and understand language
Corpus Callosum
* Communication between the left and right side of the brain
THE CEREBELLUM
* Balance
* Posture
* Cardiac, respiratory, and vasomotor centers
THE BRAIN STEM
* Motor and sensory pathway to body and face
* Vital centers: cardiac, respiratory, vasomotor
Hypothalamus
* Moods and motivation
* Sexual maturation
* Temperature regulation
* Hormonal body processes
Optic Chiasm
* Vision and the optic nerve
Pituitary Gland
* Hormonal body processes
* Physical maturation
* Growth (height and form)
* Sexual maturation
* Sexual functioning
Spinal Cord
* Conduit and source of sensation and movement
Pineal Body
* Unknown
Ventricles and Cerebral Aqueduct
* Contains the cerebrospinal fluid that bathes the brain and spinal cord
excerpt borrowed from http://www.enchantedlearning.com/subjects/anatomy/brain/Structure.shtml
Sunday, September 13, 2009
Thursday, September 10, 2009
The Structure of the Brain
The nervous system is your body's decision and communication center. The central nervous system (CNS) is made of the brain and the spinal cord and the peripheral nervous system (PNS) is made of nerves. Together they control every part of your daily life, from breathing and blinking to helping you memorize facts for a test. Nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Sensory nerves gather information from the environment, send that info to the spinal cord, which then speed the message to the brain. The brain then makes sense of that message and fires off a response. Motor neurons deliver the instructions from the brain to the rest of your body. The spinal cord, made of a bundle of nerves running up and down the spine, is similar to a superhighway, speeding messages to and from the brain at every second.
The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.
What do each of these lobes do?
* Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
* Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
* Occipital Lobe- associated with visual processing
* Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it.
A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.
Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.
The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc).
The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.
The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence
Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old.
This system contains the thalamus, hypothalamus, amygdala, and hippocampus.
Brain Stem: Underneath the limbic system is the brain stem. This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Scientists say that this is the "simplest" part of human brains because animals' entire brains, such as reptiles (who appear early on the evolutionary scale) resemble our brain stem. Look at a good example of this here.
The brain stem is made of the midbrain, pons, and medulla.
excerpt borrowed from http://serendip.brynmawr.edu/bb/kinser/Structure1.html#cerebrum
The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.
What do each of these lobes do?
* Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
* Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
* Occipital Lobe- associated with visual processing
* Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it.
A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.
Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.
The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc).
The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.
The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence
Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old.
This system contains the thalamus, hypothalamus, amygdala, and hippocampus.
Brain Stem: Underneath the limbic system is the brain stem. This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Scientists say that this is the "simplest" part of human brains because animals' entire brains, such as reptiles (who appear early on the evolutionary scale) resemble our brain stem. Look at a good example of this here.
The brain stem is made of the midbrain, pons, and medulla.
excerpt borrowed from http://serendip.brynmawr.edu/bb/kinser/Structure1.html#cerebrum
Tuesday, September 8, 2009
My Personal View - Fred Hoyle
Fred Hoyle - A Personal View [1960]
Looking to the Future
I come now to an entirely different class of question. With the clear understanding that what I am going to say has no agreed basis among scientist but represents my own personal views, I shall try to sum up the general philosophic issues that seem to come out of our survey of the Universe.
It is my view that man's unguided imagination could never have chanced on such structure as I have put before you. No literary genius could have invented a story one-hundreth part as fantastic as the sober facts that have been unearthed by astronomical science. You need only compare our inquiry into the nature of the universe with the tales of such acknowledged masters as Jules Verne and H. G. Wells to see that fact outweighs fiction by an enormous margin. One is naturally led to wonder what the impact of the new cosmology would have been on a man like Newton, who would have been able to take it in, details and all, in one clean sweep. I think that Newton would have been quite unprepared for any such revelation, and that it would have had a shattering effect on him.
Is it likely that any astonishing new developments are lying in wait for us? Is it possible that the cosmology of 500 years hence will extend as far beyond our present beliefs as our cosmology goes beyond that of Newton? It may surprise you to hear that I doubt whether this will be so. If this should appear presumptuous to you, I think you should consider what I said earlier about the observable region of the Universe. As you will remember, even with a perfect telescope we could penetrate only about twice as far into space as the new telescope at Palomar. This means that there are no new fields to be opened up by the telescopes of the future, and this is a point of no small importance in our cosmology.There will be many advances in the detailed understanding of matters that still baffle us. Of the larger issues I expect a considerable improvement in the theory of the expanding Universe. Continuous creation I expect to play an important role in the theories of the future. Indeed, I expect that much will be learned about continuos creation, especially connection with atomic physics. But by and large, I think that our present picture will turn out to bear an appreciable resemblance to the cosmologies of the future.
In all this I have assumed that progress will be made in the future. It is quite on the cards that astronomy may go backward, as, for instance, Greek astronomy went backwards after the time of Hipparchus. And in saying this I am not thinking about an atomic war destroying civilization, but about the increasing tendency to rivet scientific inquiry in fetters. Secrecy, nationalism, the Marxist ideology- these are some of the things that are threatening to choke the life out of science. You may possible think that this might be a good thing, as we have obviously had quite enough of atom bombs, disease spreading bacteria, and radioactive poisons to last us for a long time. But this is not the way in which it works. What will happen if science declines is that there will be more work, not less. on the comparatively easy problems of destruction. It will be the real science, where the adversary is not man but the Universe itself, that will suffer.
Next we come to a question that everyone, scientist and nonscientist alike, must have asked at some time. What is man's place in the Universe? I should like to make a start on this momentous issue by considering the view of the out-and-out materialist. The appeal of their argument is based on simplicity. The universe is here, they say, so let us take it for granted. Then the Earth and other planets must arise in the way we have already discussed. On a suitably favored planet like the Earth, life would be very likely to arise, and once it had started so the argument goes, only the biological processes of mutation and natural selection are needed to produce living creatures as we know them. Such creatures are no more than ingenuous machines that have evolved as strange by-products in an odd corner of the universe. No important connection exists, so the argument concludes, between these machines and the universe as a whole, and this explains why all attempts by the machines themselves to find such a connection have failed.
Most people object to this argument for the not very good reason that they do not like to think of themselves as machines. But taking the argument at face value, I see not point that can actually be disproved, except the claim of simplicity. The outlook of the materialist is not simple; it is really very complicated. The apparent simplicity is only achieved by taking the existence of the Universe for granted. For myself there is a great deal more about the Universe that I should like to know. Why is the Universe as it is and not something else? Why is the Universe here at all? It is true that at present we have no clue to the answers to question such as these, and it may be that the materialist are right in saying that no meaning can be attached to them. But throughout the history of science, people have been asserting that such and such an issue is inherently beyond the scope of reasoned inquiry, and time after time they have been proved wrong. Two thousand years ago it would have been thought quite impossible to investigate the nature of the Universe to the extent I have been describing it to you in this book. And I dare say that you yourself would have said, not so very long ago, that it was impossible to learn anything about the way the universe is created. All experience teaches us that no one has yet asked too much.
And now I should like to give some considerations to contemporary religious beliefs. There is a good deal of cosmology in the Bible. My impression of it is that it is remarkable conception, considering the time when it was written. But I think it can hardly be denied that the cosmology of the ancient Hebrews is only the merest daub compared with the sweeping grandeur of the picture revealed by modern science. Is it in any way reasonable to suppose that it was given to the Hebrews to understand mysteries far deeper than anything we can comprehend, when it is quite clear that they were completely ignorant of many matters that seem commonplace to us? No, it seems to me that religion is but a desperate attempt to find an escape from the truly dreadful situation in which we find ourselves. Here we are in this wholly fantastic Universe with scarcely a clue as to whether our existence has any real significance. No wonder then that many people feel the need for some belief that gives them a sense of security, and no wonder that they become very angry with people like me who say that this security is illusory. But I do not like the situation any better then they do. The difference is that I cannot see how the smallest advantage is to be gained from deceiving myself. We are in rather the situation of a man in a desperate, difficult position on a steep mountain. A materialist is like a man who becomes crag-fast and keeps shouting: "I'm safe, I'm safe" because he doesn't fall. The religious person is like a man who goes to the other extreme and rushes up the first route that shows the faintest hope of escape, and who is entirely reckless of the yawning precipices that lie below him.
I will illustrate all this by saying what I think about perhaps the most inscrutable question of all: do our minds survive death? To make any progress with this question it is necessary to understand what our minds are. If we knew this with any precision then I have no doubt we should be well on the way to getting a satisfactory answer. My own answer would be that mind is an intricate organization of matter. In so far as the organization can be remembered and reproduced there is no such thing as death. If ordinary atoms of carbon, oxygen, hydrogen, nitrogen, etc., could be fitted together into exactly the structural organization of Homer, or of Titus Oates, then these individuals would come alive exactly as they were originally. The whole issue therefore turns on whether our particular organization is remembered in some fashion. If it is, there is no death. If it is not, there is complete oblivion.
I should like to discuss a little further the beliefs of the Christians as I see them myself. In their anxiety to avoid the notion that death is the complete end of our existence, they suggest what is to me an equally horrible alternative. If I were given the choice of how long I should live with my present physical and mental equipment, I should decide on a good deal more then 70 years. But I doubt whether I should be wise to decide on more then 300 years. Already I am very much aware of my own limitations, and I think that 300 years is as long as I should like to put up with them. Now what the Christians offer me is an eternity of frustration. ANd it is no good their trying to mitigate the situation by saying that sooner or later my limitations would be removed, because this could not be done without altering me. It strikes me as very curious that the Christians have so little to say about how they propose eternity should be spent.
Perhaps I had better end by saying how I should arrange matters if it were my decision to make. It seems to me that the greatest lesson of adult life is that one's own consciousness is not enough. What one of us would not like to share the consciousness of half a dozen chosen individuals? What writer would not like to share the consciousness of Shakespeare? What musician that of Beethoven or Mozart? What mathematician that of Gauss? What I would choose would be an evolution of life whereby the essence of each of us becomes welded together into some vastly larger and more potent structure. I think such a dynamic evolution would be more in keeping with the grandeur of the physical Universe than the static picture offered by formal religion.
What is the chance of such an idea being right? Well, if there is one important result that comes out of our inquiry into the nature of the Universe it is this: when by patient inquiry we learn the answer to any problem, we always find, both as a whole and in detail, that the answer thus revealed is finer in concept and design than anything we could ever have arrived at by random guess. And this, I believe, will be the same for the deeper issues we have been discussing. I think that all our present guesses are likely to prove but a very pale shadow of the real thing; and it is on this note that I must now finish. Perhaps the most majestic feature of our whole existence is that while our intelligences are powerful enough to penetrate deeply into the evolution of this quite incredible Universe, we still have not the smallest clue to our own fate.
Looking to the Future
I come now to an entirely different class of question. With the clear understanding that what I am going to say has no agreed basis among scientist but represents my own personal views, I shall try to sum up the general philosophic issues that seem to come out of our survey of the Universe.
It is my view that man's unguided imagination could never have chanced on such structure as I have put before you. No literary genius could have invented a story one-hundreth part as fantastic as the sober facts that have been unearthed by astronomical science. You need only compare our inquiry into the nature of the universe with the tales of such acknowledged masters as Jules Verne and H. G. Wells to see that fact outweighs fiction by an enormous margin. One is naturally led to wonder what the impact of the new cosmology would have been on a man like Newton, who would have been able to take it in, details and all, in one clean sweep. I think that Newton would have been quite unprepared for any such revelation, and that it would have had a shattering effect on him.
Is it likely that any astonishing new developments are lying in wait for us? Is it possible that the cosmology of 500 years hence will extend as far beyond our present beliefs as our cosmology goes beyond that of Newton? It may surprise you to hear that I doubt whether this will be so. If this should appear presumptuous to you, I think you should consider what I said earlier about the observable region of the Universe. As you will remember, even with a perfect telescope we could penetrate only about twice as far into space as the new telescope at Palomar. This means that there are no new fields to be opened up by the telescopes of the future, and this is a point of no small importance in our cosmology.There will be many advances in the detailed understanding of matters that still baffle us. Of the larger issues I expect a considerable improvement in the theory of the expanding Universe. Continuous creation I expect to play an important role in the theories of the future. Indeed, I expect that much will be learned about continuos creation, especially connection with atomic physics. But by and large, I think that our present picture will turn out to bear an appreciable resemblance to the cosmologies of the future.
In all this I have assumed that progress will be made in the future. It is quite on the cards that astronomy may go backward, as, for instance, Greek astronomy went backwards after the time of Hipparchus. And in saying this I am not thinking about an atomic war destroying civilization, but about the increasing tendency to rivet scientific inquiry in fetters. Secrecy, nationalism, the Marxist ideology- these are some of the things that are threatening to choke the life out of science. You may possible think that this might be a good thing, as we have obviously had quite enough of atom bombs, disease spreading bacteria, and radioactive poisons to last us for a long time. But this is not the way in which it works. What will happen if science declines is that there will be more work, not less. on the comparatively easy problems of destruction. It will be the real science, where the adversary is not man but the Universe itself, that will suffer.
Next we come to a question that everyone, scientist and nonscientist alike, must have asked at some time. What is man's place in the Universe? I should like to make a start on this momentous issue by considering the view of the out-and-out materialist. The appeal of their argument is based on simplicity. The universe is here, they say, so let us take it for granted. Then the Earth and other planets must arise in the way we have already discussed. On a suitably favored planet like the Earth, life would be very likely to arise, and once it had started so the argument goes, only the biological processes of mutation and natural selection are needed to produce living creatures as we know them. Such creatures are no more than ingenuous machines that have evolved as strange by-products in an odd corner of the universe. No important connection exists, so the argument concludes, between these machines and the universe as a whole, and this explains why all attempts by the machines themselves to find such a connection have failed.
Most people object to this argument for the not very good reason that they do not like to think of themselves as machines. But taking the argument at face value, I see not point that can actually be disproved, except the claim of simplicity. The outlook of the materialist is not simple; it is really very complicated. The apparent simplicity is only achieved by taking the existence of the Universe for granted. For myself there is a great deal more about the Universe that I should like to know. Why is the Universe as it is and not something else? Why is the Universe here at all? It is true that at present we have no clue to the answers to question such as these, and it may be that the materialist are right in saying that no meaning can be attached to them. But throughout the history of science, people have been asserting that such and such an issue is inherently beyond the scope of reasoned inquiry, and time after time they have been proved wrong. Two thousand years ago it would have been thought quite impossible to investigate the nature of the Universe to the extent I have been describing it to you in this book. And I dare say that you yourself would have said, not so very long ago, that it was impossible to learn anything about the way the universe is created. All experience teaches us that no one has yet asked too much.
And now I should like to give some considerations to contemporary religious beliefs. There is a good deal of cosmology in the Bible. My impression of it is that it is remarkable conception, considering the time when it was written. But I think it can hardly be denied that the cosmology of the ancient Hebrews is only the merest daub compared with the sweeping grandeur of the picture revealed by modern science. Is it in any way reasonable to suppose that it was given to the Hebrews to understand mysteries far deeper than anything we can comprehend, when it is quite clear that they were completely ignorant of many matters that seem commonplace to us? No, it seems to me that religion is but a desperate attempt to find an escape from the truly dreadful situation in which we find ourselves. Here we are in this wholly fantastic Universe with scarcely a clue as to whether our existence has any real significance. No wonder then that many people feel the need for some belief that gives them a sense of security, and no wonder that they become very angry with people like me who say that this security is illusory. But I do not like the situation any better then they do. The difference is that I cannot see how the smallest advantage is to be gained from deceiving myself. We are in rather the situation of a man in a desperate, difficult position on a steep mountain. A materialist is like a man who becomes crag-fast and keeps shouting: "I'm safe, I'm safe" because he doesn't fall. The religious person is like a man who goes to the other extreme and rushes up the first route that shows the faintest hope of escape, and who is entirely reckless of the yawning precipices that lie below him.
I will illustrate all this by saying what I think about perhaps the most inscrutable question of all: do our minds survive death? To make any progress with this question it is necessary to understand what our minds are. If we knew this with any precision then I have no doubt we should be well on the way to getting a satisfactory answer. My own answer would be that mind is an intricate organization of matter. In so far as the organization can be remembered and reproduced there is no such thing as death. If ordinary atoms of carbon, oxygen, hydrogen, nitrogen, etc., could be fitted together into exactly the structural organization of Homer, or of Titus Oates, then these individuals would come alive exactly as they were originally. The whole issue therefore turns on whether our particular organization is remembered in some fashion. If it is, there is no death. If it is not, there is complete oblivion.
I should like to discuss a little further the beliefs of the Christians as I see them myself. In their anxiety to avoid the notion that death is the complete end of our existence, they suggest what is to me an equally horrible alternative. If I were given the choice of how long I should live with my present physical and mental equipment, I should decide on a good deal more then 70 years. But I doubt whether I should be wise to decide on more then 300 years. Already I am very much aware of my own limitations, and I think that 300 years is as long as I should like to put up with them. Now what the Christians offer me is an eternity of frustration. ANd it is no good their trying to mitigate the situation by saying that sooner or later my limitations would be removed, because this could not be done without altering me. It strikes me as very curious that the Christians have so little to say about how they propose eternity should be spent.
Perhaps I had better end by saying how I should arrange matters if it were my decision to make. It seems to me that the greatest lesson of adult life is that one's own consciousness is not enough. What one of us would not like to share the consciousness of half a dozen chosen individuals? What writer would not like to share the consciousness of Shakespeare? What musician that of Beethoven or Mozart? What mathematician that of Gauss? What I would choose would be an evolution of life whereby the essence of each of us becomes welded together into some vastly larger and more potent structure. I think such a dynamic evolution would be more in keeping with the grandeur of the physical Universe than the static picture offered by formal religion.
What is the chance of such an idea being right? Well, if there is one important result that comes out of our inquiry into the nature of the Universe it is this: when by patient inquiry we learn the answer to any problem, we always find, both as a whole and in detail, that the answer thus revealed is finer in concept and design than anything we could ever have arrived at by random guess. And this, I believe, will be the same for the deeper issues we have been discussing. I think that all our present guesses are likely to prove but a very pale shadow of the real thing; and it is on this note that I must now finish. Perhaps the most majestic feature of our whole existence is that while our intelligences are powerful enough to penetrate deeply into the evolution of this quite incredible Universe, we still have not the smallest clue to our own fate.
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